We had an incident a few years ago when our electric storage heaters stopped working. When the electrician investigated, he opened the (metal) box containing the switchgear to find that there had been a fire in it - but it was so well contained that we didn't even smell it. Had the box been made of plastic, I suppose we might not still have a house.
YES, that's why the amendment was made. Even more scary inasmuch that it was storage heaters... you and your family would have been well asleep before the fire started. Glad you had good fortune!
American electrician here. I've always been interested in your distribution panels so this was an interesting way to get a first look! We use a similar set up mostly only for motor controls though. One of the first things I learned years ago was ALWAYS double tighten your main lugs at the end of the job! So important, unfortunately some manufacturers seem to be getting so cheap it can cause stripping out of the lug screwhead. Great video, happy holidays.
it's often missed by actual electricians too. End of the job for us, on every job, is tighten every screw on the distribution board(s). Even if we've been nowhere near it. Cover Your Arse
Whenever i open a board i always check the screw that holds the incoming active first. I had it jump out on me once when i was pulling a new cable in... not fun. It only takes a second and i have found many loose mains connections over the years.
It feels weird seeing you describe something I think of as a modern consumer unit as outdated. I'm still in the mindset where having a RCD at all means it's modern as I grew up with those old fuse boxes full of blade fuses people used to repair themselves with fuse wire (or occasionally a 2p piece or a rusty nail).
I've experienced the issue you described about the tails becoming loose after being initially tightened correctly . As a storman for site electrical engineering company I was building a 3 phase 100a mdu and terminated everything and correctly tightened the terminals on the RCD etc . I thereafter decided to manipulate the route the tails took to make everything look neater without going back to check the terminals . Needless to say once the unit was installed on site by a colleague he called to inform me that one of the phases had come out of the RCD and almost gave him a nasty suprise . Lesson learned . As you say its surprising how much the terminals can loosen off if you manipulate the tail after the fact .
Nick has done work for me. Fantastic job. A video from 12 months ago was him rewiring my house. I have learnt a lot from both of your videos. ;) keep smiling keep safe everyone. ;)
Clive, please wear gloves when handling burt plastic! In the service we were warned of acid release following the product being exposed to heat of sufficient intensity to cause charing. Some of the acids can permeate the skin and cause health issues years down the line. Keith
I think it depends on the plastic, but it's always better safe than sorry. PVC would probably be the one to do that, and this part might be PVC or ABS.
In the auto body repair industry, we were warned over 20 years ago to avoid direct skin contact with plastic body and mechanical components which had been the subject of fire. We were advised of a chemical which was released from some types of burnt plastic which, if got onto the skin, would continue to eat into the skin, and nothing would stop it. The only cure was - AMPUTATION!!!
@@grotekleum "Yeah, hydrochloric acid I believe it is. Nasty stuff." Close, hydroflouric acid. It leaches into the skin and sometimes the only way to stop it is amputation.
In the US, "breaker panels", have been steel for as long as I can remember. I'm 62, and have been servicing panels, since I was 16. As for arc fault, or ground fault protection, that's done at the individual breaker level. In case of ground fault, that's mostly done at the outlet, but ground fault breakers are available. Breaker bodies are made of flameproof bakelite, which also does not melt. For 120V, connect to one breaker, and one neutral. For 240V, connect to two adjacent breakers, as common homes have "split phase", where the phases are alternated at every breaker location (A-B-A-B .... -A-B). In non-industrial commercial locations (ie stores), there usually is 208V/120V 3-phase. 440V/277V 3-phase in large office buildings an small industrial sites.
This video gave me anxiety over the electrical panel at my moms place where I did the distribution board diy style from scratch when I was 15. We moved houses and in the new house there was only the main cutoff and one RCD for the whole two storey house, so I took upon myself to rewire the house as best I could and I installed a box with 20 different breakers and I sorted lights, normal sockets, powerful sockets for dishwasher, clothes washer, electrical boiler, etc. and I ran wires on the walls directly in the neat narrow plastic cunners and the majority of the cables I run inside the hollow baseboards along the floors. That was 7 years ago. When I visit her I always check it. Still works like a charm. I only did that because I was very bonkers on electronics and I had a lamp collection of 3000 lamps by the time I was 15 and I had a powerful variac and used a MOT to demonstrate my friends how electricity makes arcs and blows up fluorescent tubes. I was actually inspired by you Clive, I watched your videos since I was 10.
The wires with the high strand count caught my attention, this reminds me of a connection issue we had in a 200A, 12VDC circuit. The wire involved was made to be very flexible, high strand count, 32AWG strands. The flexibility was required to allow servicing the power converter. The termination crimps on the wire would slowly increase in resistance and heat up. It would often take months of operation for the flaw to get dangerously hot. It is hard to get a good mechanical connection by compression alone with such fine malleable copper wire.
@@S己G it's a reference to the "this is fine" meme with the dog in a burning house. tenor.com/view/joke-not-getting-the-joke-flew-over-your-head-stickman-gif-16997031
just installed a water heater today, the 240v supply coming into the old one, all the insulation on the inner core was cracked on the neutral. some retard wrestled it too much 20 years ago when installed. awful it sat that way that long!
I went to do a job recently at a town house that had had a similar consumer unit fire in its basement. The fire had affected the two floors above and needed new floors afterwards. My advise is always to fit smoke detectors and suitable fire extinguishers in such areas as these incidents seem to be becoming more common.
I've long admired the well-thought-out lamp / appliance plugs that the UK now uses (as we still use an evolved version of a very, very old design here for our lamps and small appliances), but compared to the heavy, all-metal breaker box on my house here in Arizona, that plastic box looks like a (terrifying) toy! 😲 I'm not an electrician, so I've never personally installed a breaker box (and have no expertise, of course), but I've seen it done here, and every working part of it looked much more heavily built, aside from the housing of the unit, too. Very interesting! I'll still give points on the UK's fancy lamp plugs, though; very well-engineered.
Finally, an ASMR video of crispy well done breakers. Probably what job security sounds like to an electrician. Should make one of those 8 hr videos to lull electricians off to sleep.
After doing thermal surveys for nearly 20 years, I’ve found the point at fault is mostly the area with the least debris. (i.e. the hottest point tends to vapourise any insulation near by). In your video the things that pop out for me, are the 2 Neutral cables onto the Neutral busbars, not onto the switch. Also the area were these would be is near the top main cable connections, which is showing burnt insulation, but not vaporised insulation. They also look discoloured & missing the insulation at one end only. It’s only a theory! Keep up the excellent work.
In the US, when I replace breakers or wire up buss bars/panels, I always check the device torque ratings and use a torque wrench. It's usually a 1/2-full turn tighter compared to using a hand screwdriver. I also let it sit for a several days, then recheck all connections. I've found a few that have gotten slightly loose from deformation or temperature variation.
Again Clive, an excellent in detail analysis of a messy outcome! After seeing this, one wonders why the whole device was constructed from concept in the way it was. In a catastrophic fault/short/overload event, too much use of moulded parts I feel is not conducive to being robust enough to handle the heat and consequent burn outs which result. Some manufacturers make a better product than others, very evident when comparing these kind of units. Great video and talk through, thank you🙂👍
the meter/cables are supposed to smell a bit like rotten fish when they begin to melt to alert you to something going wrong. So it probably smelt even worse on fire
Electro professional for 35 years here. In my opinion, the cause of fire looks like poor contact in connection clamps. Always double check all connections that you tighten with the right torque. And just as important; finally always pull the wire to know that it attaches properly. Several times I have discovered wires that I myself have connected and tightened, and which I can pull straight out of the connection point afterwards😲Always double check. Great video Clive😀
Hi Clive, I didn't expect that, there is a lot different compared to our panels here in Belgium, we have 2 RCDs to but they ane of 30mA for damp or humid areas (bathrooms and laundry rooms, garden sheds outside lighting) and a 300mA for the rest of the house and the breakers are all double pole (N and L and a separate ground busbar).
Or a bar that sells Green organic free range juices and other things equally hippy and a sign that says something like ‘no shoes, no shirt Yes service’ 🤣
if i was a betting man, i’d suspect one of the neutrals from the RCD’s where it terminates in the neutral bars. I’ve seen several of these burn out in electrium consumer units in my 20 years of sparking. a bad design as the cores generally touch the plastic immediately behind the bars, so if they are loose, that heat transfers straight to the plastic. i’ve seen several with big melted holes in the top of the unit due to loose neutrals in the bars, including one that went on fire, albeit not quite as dramatically as the one in this video.
Electrical technician in training here (gettting my certificate in February) this still looks super safe, compared to the things I ran in to already... The old cheramic melting type breakers... With fillament replaced with (at least) 4 mm thick iron nail... Glowing under load. In a woodworker's shop.
In over 30 years of being a qualified spark, I have never seen one of these plastic boards go up in flames ! I have seen them in house fires getting destroyed (but are not the original cause).
The ones in the 1970s and 1980s were made from an entirely different type of plastic closer to Bakelite. The change in the law Clive mentions was after the London Fire Brigade saw a doubling of the number of consumer in about three or four years due to dodgy units like this.
This is the perfect reminder to do my annual inspection of my breaker panels. Most of it I'm not concerned with, just the aluminum service lines, make sure there isn't any corrosion and the lugs are tight.
From what I learned watching Nick and Artisan Electrics, the danger is not so much with the material of the box, but how well the wiring inside it is done.
@@Alexander_l322 Also the manufacture of the components which were getting stupidity "thin". Which would be fine(ish) if the metals and plastic were of a good enough quality, but if you are making the conector bars to just big enough to cope and are also cheapening the metal mix of the brass, you've taken out most of any redundancy.
Great video, being from the USA it's super interesting for me to see how other countries and regions do their power distribution, and learn about the differences and similarities. Thanks!
It is stupid, when the average house price is c £270000 that they make and fit stuff like this. I replaced my consumer unit (back when you were allowed to) in a house thirty years ago and then unit cost much more back then than they do today. Also Kudos to Laing's for fitted a big metal cased 100A switch between the meter and the consumer unit back when they built the house back in 1980.
@@MrDuncl A building inspector once told me: “Don’t do a job much better than a good contractor would - it stands out and raises suspicion that a homeowner with too much knowledge and time on their hands did the job, and it won’t matter that the job may be done perfectly”. I never heeded that advice, though. I’m averse to the specter of electrical fires.
@@MrDuncl *It was not an equipment failure.* Wylex do make good stuff. These day it is best to install DP RCBOs with no earth flylead. The price of them is dropping, so now affordable. I have all my heavy appliances on their own circuit with their own RCBO. All circuits are on RCB's. Having say the kitchen appliances on their own kitchen ring with mcb's and a RCD, may cause nuisance RCD tripping, with cumulative earth leakage form appliances. That means one appliance the earth leakage is less than 30Ma, so safe - say the w/machine is 20Ma. Then the dishwasher develops a 20Ma leakage, then the kettle does six months later. Have them on all together they are above 30Ma so the RCD trips, with half the house without power. RCBO's dvide and rule, and are much safer.
@@johnburns4017 I would say it was an equipment failure once the initial fault (which may have been due to poor installation) caused the unit to start burning. That was why the wiring regulations were changed to specify metal enclosures. From a fire safety point of view I would have more confidence in the old Bakelite style Wylex boxes from the 1960s which when tested just smelt and discoloured a bit than this flammable plastic one.
yes, with UK meter tails (especially the 7 strand type) it pays to bend them first then trim and terminate, people forget the different radii, i've seen so many where 3 out of the 7 strands have missed the main switch!
@@TheChipmunk2008 - I’ve seen an industrial installation when the cable missed the clamp entirely (okay this was a DIN rail fuse holder rather than in a CU) and the installer tightened the clamp past the conductor leaving the cable conductor unsecured and only just touching the terminal. This on the incoming side. When fault finding, I was trying to work out why the voltage kept going when I probed the incoming terminals with the meter, but was steady on the outgoing terminals. But of course, being on a DIN rail, it was moving slightly when I pushed the meter probes on to the relevant terminals... The problem could not be seen directly due to cable trunking.
@@Mark1024MAK omg THAT happens SO often on solid busbars (as used in the UK in distribution boards). So much so that CK and Knipex (I think) both sell 1000v insulated dentist style mirrors to check underneath. Usually an easy diagnosis if the customer complains of a burning smell and the breaker is discoloured even slightly. (takes very little actually discolouring to absolutely STINK), as I'm sure you know. I sometimes think the method of using stranded cable (NOT 7 strand, which i regard as Solid in larger sizes) as a busbar avoids this, as loose connections are easier to find with a 'tug test'
Yeah, I concur about your opinion about tightening things by hand. I'm not an electrician, but from a mechanics point of view, there is a time and place when to use a torque wrench, often if you go in heavy handed, especially into aluminium, you risk damaging the the item. So it's best to get a feel with your hand. And only torque as the final measurement.
Very common, we have two in our house. One was installed just before the announcement on changing to metal. So important to check and re-check the tightness on the multi-core connections. Worth getting these tested every few years - like you do for you car.
When i learned to wire in germany, we were always told to either use solid wire, or crimp on a wire ferrule... We were absolutely forbidden fron just clamping down straight, stranded wires.
Over here, any house panel (Or commercial/industrial panel, for that matter) has thick aluminum lugs with concave cuts the wire is pressed into, and Allen (hex) head setscrews. Of course, our smallest wire size for services is #1AWG. 2/0-4/0 more commonly for a home these days, as 100A services are no longer code on dwellings. 150A minimum. Commercial businesses are generally anywhere from 250MCM (kCM) to 750MCM, although they do make wire up to 2000MCM. I can pretty much guarantee you really ain't gonna put a ferrule on those. But Clive is absolutely right. Bend your wire into the final shape before you place it under the lug. It's hard to believe some dink would do otherwise, and rely on the lug for support during bending. But I guess they have mechanically disinclined retards everywhere.
You should always go over all the circuit breaker terminations several times. You should also check the screws annually because the temperature fluctuations may even loosen them. You can tell if a screw is tight enough, when unscrewing it should be very tight and the screw should make a distinct cracking sound as it comes free.
In the future Clive will be a coroner for robots. "Now let's see. How did this robot die? Ah yes. Now I see. Someone shoved a penny in his fuse holder."
@@tinytonymaloney7832 Thanks. Glad it made you smile. Lol. As does Clive with his spudger, and detailed and insightful explanations. Cheers from Canada.
My fuse box recently experienced arcing as a result of a poor connection in one of the fuse bases. For a few years ago our lights would occasionally shimmer sometimes. Over time it got worse, with lights sometimes taking unto a minute to come on, or sometimes turning on a light would cause other lights to extinguish. Eventually our lights switched off one day and we discovered the problem. Luckily our fuse box is made of asbestos, which is both a good and a bad thing...
From experience, the contacts don't look that bad, it's more likely to be loose terminals, i've seen industrial boards where the insulation of the wire has got very hot and melted back, then found the terminal a little loose Many industrial boards only have one sided din rail (of sorts) with the busbar supporting the other end, in the wylex one end of the busbar is held in the main switch which is fully clipped, the other is in that support, if you need to change a breaker, you don't have to remove the busbar, just undo the screw and slide it up.
I meant to add that i always tried to fully form the bend (preferably without switches or breakers in the way) before cutting and stripping, then you don't get the long strands stopping the cable from being fully inserted ;)
Something like that occured in my back room. My shop was once a laundromat, so Ole Sparky is 7'Tall, 2' deep and 3' wide.... Annual fire dept visit now uses a thermal reader... they found 3 very hot breakers. Elekchicken fixed it same day. Disaster averted.
The redundancy of the safety precautions is incredible... I think the UK has probably the safest electrical standards in the world. I wish we had that kind of redundancy here in the USA. Unfortunately most people only care about the cost of these systems here, so they typically go with the cheapest solutions. They probably don’t realise that a fire caused by electrical failure costs far more than precautionary implementations / devices. When I get a house, I’m definitely going to invest in a UK-style wiring format for my house.
Things are rather different in the US... :-) What you're calling an isolator I'd call a main breaker. In this old house there wasn't one, but instead a separate box with a couple of huge cartridge fuses in it, rated at 150A I think. Some time back our power got weird, some stuff worked and other stuff didn't. It looked like we had one phase of the two that were coming in off the pole transformer. On contacting the power company we were told that the smart meter was seeing both connectiojns but they sent someone out anyway. It turned out that the weatherhead-meter-ingress stuff had leaked moisture into the fuse box which was in the basement, which caused it to blow. After a while an electrician came out and replaced the whole setup, from the weatherhead on in and including the breaker box, so we now have a main breaker instead of that box and it's all well sealed to keep the weather out of the wiring and we presumably won't have a problem again. I've never seen anything other than metial used for a breaker box, including the one in the house, one in the garage, and a load center in an outbuilding (which I installed). Plastic? No thank you!
I'd be more concerned as to how the flame had continued to burn and spread - regardless of a hot spot (arcing fault), you should not get full combustion of the board. It just shouldn't happen. Two possible causes for that amount of damage; 1. lack of (or non-compliant) retardant in the polymers (casing or insulation batch failure), or more unlikely 2. high current thermal runaway on one of the insulated conductors that ran horizontally over the top of the breakers (but why the fuse(s) wouldn't have fused/tripped is another question). I challenge anyone to try and ignite those plastics, especially in an enclosed space with little oxygen, and get them to burn that way.
Right, there's something reassuring in the chunky old fashion North American breakers. I feel like I could break one of those plastic switches. Also, a metal case just makes sense.
@@bryanhumphreys940 It looks quite identical to the stuff I use in the Netherlands and can tell you that it will be very hard to break such plastic switches ;) . Metal cases are long gone in the Netherlands for standard consumer-units and to be honest, I've never even seen metal-case consumer units, it was either marble as a baseplate with bare connections and switches, than came porselain, eventually bakelite and then just, well, plastic (don't know what kind of plastic, but I think PC). Industrial boards used to have bare wires and connections on marble baseplates before porcelain. Than metal enclosures for long, until glassfibre reinforced stuff hit the market. Bakelite was used as well, but metal was usually preferred.
@@madmanmapper It depends. ABB's bussbar-system is becoming more common, but replacing just 1 breaker in a panel can be a pain in the ass, as, just like this UK consumer unit, the DIN-rail click-on stuff is rather standard.
My work uses those kinds of breakers all the time in industrial control panels. Neat to see them being used in residential in the UK. Here in the US residential breakers .... basically do whatever the crap they want, with each manufacturer using a completely different (not to mention completely incompatible and varying levels of unsafe behind the control panel) system to install and power the individual breakers.
Oh yeah in my partners old flat someone had done some illegal wiring to splt the building into two flats, moved the electric meter and installed a second one. We noticed smoke in her flat if the shower and the oven were run at the same time, I did some poking about and noticed some charred wood behind the two tails as they came out the meter and into the consumer unit. An electrician came out (eventually, the landlord's solution was "don't cook and shower then..."), they said "I'm not allowed to touch that bit, you need the electricity board", they turned up and said "who the F*ck installed this?". Turns out the tails were arcing between themselves as the insulation had failed.
@@eDoc2020 it would not have arced if the isolation was fine... I know it often won't trip the breaker but the breaker should have tripped way before it started arcing. Wy? Simple..... I think the combination of electric heated water and the high current from the oven combined overloaded the cables and melted the isolation to the point it started arcing.
We rented a static caravan in which there was a big switch to actually stop you using the shower and the cooker at the same time. I don't know which country you are in but what is the point of installing an electricity meter if the electricity board doesn't know it is there ?
@@MrDuncl what do you mean? If you hook up a second electricity meter behind a electrical distribution board you can see how much electricity the second board used. You just have to read the main electricity meter and remove the summ that the second unit counted.
Not that I'd *ever* make fun of what looks to be a horrible event for someone else; looking at the linked vid, it seems no one was injured, and the fire was very well contained -- both amazing, IMO. But I do feel vindicated for long questioning the quality and wisdom of implementing those plastic mains distro enclosures, often met with "I've never had a problem." I always wondered what happens if the metal gets hot and the plastic melts. Well...now we know. Thanks for the crispy 'n crunchy autopsy, Clive!
My house (I'm in uk) still has a black plastic box from the 1960s, with Wylex fuses. The incoming mains is tarred cloth and has served the house since 1931, probably. I also got some VIR wiring in the house too. I know its historical but I think Wylex wired fuses are still a BS standard.
Agree, I don't think US mains panels have ever been anything but steel. That said, plastic is the material of choice in residential outlet and switch boxes.
@@ec8107 when I was in the states I remember the fuse holders being made of glass,like a round cylinder and a grey metal box. I was in Alabama so I'm not sure if regulations change from state to state. I don't miss window AC though!!
@@wesleymays1931 not int he same way, but we did try using aluminum wire for a while in the 70's. Also, the Federal Pacific breaker panels that would weld themselves closed and to the bus bars, only recalled mains panel in US history
Had to replace a Shower pump years ago, changed it it wouldn’t work. Checked the supply Reverse polarity Everywhere... called the board.. shut the house down. Turned out a car 10 years prior hit a lamp post outside very close to incoming supply to house. Guy who cut the cable outside switched em round never checked inside the house 🤦♂️💥 was like that for 8 years. Interstellar video Clive.
we use vertical rows too, but not in small domestic installs. Ring mains mean 1 or 2 breakers for the entire flat/apartment intead of (much safer) radials to each set of outlets (Ring mans had a purpose in the 1950s when there was a copper shortage, They should have been outlawed by the 1970s regardless of fused plugs. Radially wired houses are perfectly safe and legal in the UK with a big advantage that losing one breaker DOESN'T result in losing half the house)
Brown,black and grey are the phase colour's in the EU. Blue is the neutral and green/yellow is earth. The horizontal breakers are Standard in most of the installations in the EU. Where the differences come in is that in Germany for example we have 3phase power to each house and load balance manually and create a local "star point" (i don't know the proper translation) In France it's mostly the same but better sockets then the German "Schuko" , in the UK they only have one phase for a average home that needs to carry some huge current and this is a design that asking for trouble in my opinion. And the ring main is antiquated and needs to go. It keep the consumer unit small but it keeps causing problems and is a pain to install.
Here's my diagnosis based on the evidence presented. We have a L+N supply to the top of the isolator. from there we have 2 L+N unfused going to the RCDs. There is one pair of these that are completely devoid of insulation and I'm suspecting it was the pair to the RH RCD. I suspect the fault has been with these wires as clearly, they've been the hottest. That means there has been nothing inside the CU to protect against a fault at that point and being close to the main supply wires, has damaged those too. So, of the suspect pair, I'm guessing a strand or two from L or N has been free of the terminal to link across to the other creating a dead short. Quite possibly strands of N linking across to L. On that basis, a Wylex manufacturing fault in failing to install all the strands into the terminals feeding the RH RCD. OR for whatever reason, the local sparky had removed those wires for some reason and refitted them badly/incompletely. I don't see any evidence of a fault in any component therein.
This is why I check my circuit breaker box from time to time in my basement, especially when I run high amperage devices like electric heaters. One time a wire had become oxidized from age and lost proper contact in my box. The side of my box became so hot even when running something of rather low power consumption like a fan, that the insulation on the wire and some plastic holding clips on the common junction started to melt! This could have been a major disaster! This also happened in my sister's house and she has the infamously dangerous aluminum wiring. I tell people to once in a while check your circuit box, especially if you have an old home! You may be glad you did! 👍👍
@bigclivedotcom Clive, I don't fully understand electronic mate, so on the Wylex board, the non-burnt one you showed, what is the purpose of the two yellow buttons on the RCD slots? And what is a RCD and it's purpose? lol
An RCD or GFCI compares the current going out to the current returning. If they are significantly different due to a fault or someone receiving a shock, it turns off the power.
That pre-wired consumer unit surprises me as a Kiwi. Here we're limited to three circuits per RCD, whereas you have five on that board. You also switch the supply neutral which begs the question - how does UK grounding work? Here in NZ our neutrals are tied to ground potential at several points in the distribution network, as well as inside the distribution board (via MEN link). We usually have the incoming neutral going to a bar, and from there supplying our RCDs, as well as linking to the ground bar. Are your neutrals grounded prior to the consumer unit?
It's fairly common to see all the circuits for a house on a single RCD in the UK in older consumer units that have RCD protection, though the regulations don't permit that now. Our neutrals are often connected to earth at several points along the distributors supply network (PME) but neutral and earth must kept separate in consumers installations. The neutral is switched as it is common for the electricity supplier to not provide any earth connection or the neutral is only connected to earth at the transformer so the neutral might not be at 0V to earth on some supply arrangements.
Yes like Echo says, it's quite common to see everything on a single RCD, or even more common to see RCDs on sockets but not on lights. And yes, the neutrals are grounded throughout the network if PME* PME is similar to MEN, with the difference that the link is on the supplier's side, rather than the customer's side. (the link is in the service head with the main fuse, not in the consumer's DB) . Both are subtle variants of TN-C-S. The reason for opening the neutral is (in my guess) twofold: 1, the historical use of RCD's as main switches,. and 2, the fact that neutral is considered a 'live' wire under the 18th edition of the wiring regs *ALLEGEDLY
I have one of these! However, I do inspect it quite regularly, and give it a good health check before winter sets in. I have admit though, that's a sobering sight on your bench.
I have a contactor that has done something similar thought not to the same degree. The cause: 65yo engineer inserted 8AWG(I think), it should have ben 6AWG along the screw that applied pressure to the clamp. Tightened the clamp and it drew the cable into the screw slightly but did not successfully clamp the cable. That was a fun repair. Contactor was part of/installed inside a Heller reflow oven. I still have it if you would like some pics. I considered sending it to you but the shipping would be horrendous. Timeframe was conveniently right when you did your video tearing down a very similar contactor like within days. We moved our factory in the middle of that repair and I think there a few missing pieces to the old contactor but you can get the gist of what was going on. I may even have some old photos taken on my back of the burned unit still installed inside the machine and some of the cable damage.
Late watching this but the one before was AVE putting Metal Plates into a bucket of brine as a load tester and watching for minutes on end drawing 24Amps through a 20Amp breaker waiting it to trip. I'll link this for him.. Chuckle... (Edit, you beat me to it in his comments!)
Damn, my last comment didn't post properly. I'll try again. I don't think the source of the fire was the isolator contacts, they are far too clean, I would also expect the plastic parts that actuate them to be melted, they are not even brown. The RCD to the left of the isolator is also almost undamaged, though the most of the melting seems to be on the neutral side at the right of the isolator. Most major contact heating I have seen also damaged the adjacent module. I have seen main switches by Hager, MK and CGD with contact faults, the inside of the switches were all badly burned where as the screw terminals and outer casings were largely undamaged. I'll try and dig out the photos. Could it be possible the fire started at the top of the consumer unit at one of the neutral bars, perhaps the right hand one? I have seen lots of thermal damage in consumer units from failed contacts and terminals, but I've only seen fires (2 of them) from poor connections at neutral bars setting fire to the not so heat resistant enclosures the bars are directly in contact with. I have a burnt connection here I took out of a 100A MEM Exel switchfuse, the 35mm2 cable was poorly installed. The copper is fairly clean where it was inside the terminal, despite the heating, above the terminal it is very green. One of the strands has erroded away from the arcing, some of the others have little pits melted in them where arcing has occurred. The PVC is rock solid. imgur.com/a/3SlFClL That's my thoughts and experiences from the last 17 or so years anyway!
yep with you 100% on it being a loose neutral. The fact that the fire started at the top and worked its way down amplifies that A lot of 'electricians' also think of the 'neutral bar' as less important because "it's not live, right?" so they check for tightness at the breakers, and tails, but ignore the neutral bar I despair at that mode of 'thought'.
Never really thought about it before now, but all the breaker boxes I've ever seen in person (here in California) were indeed metal. On the one hand, I'm a bit surprised they never tried plastic, but on the other, this video.
My consumer unit is in my porch which looking at that mess is probably a good thing, even if it is directly in a main exit from the building. Although this is a new house built in 2018 so the consumer unit is a metal box, and there's also an isolator switch between the main fuse and the entire consumer unit next to the meter outside. It's certainly an improvement from the old bakelite Wylex fusebox in my old house that had the ancient wire-wound cartridges and was right next to the gas meter, in the cellar, about two inches from the ceiling...
Interesting vid and post mortem - I can almost smell the foul fish-like stench of burnt fuseboard through the screen.... You've a new subscriber :) As an electrician, I've seen my fair share of burnt out MCBs and Main Switches - as a general rule tho, very few reach this stage of destruction. In most cases, its caused by a poor connection (either not tight enough caused by overheating or human error during installation) or poor environmental conditions causing corrosion and tarnish in the terminals, which in turn overheat, tarnish further, overheat more.... you get where this leads. In most Main switch cases, the insulative barrier between the live and neutral terminal breaks down first, causing contacts to meet and a dead short that trips the main isolator itself or takes the DNO fuse. This time it didnt happen and things got serious :( In a majority of cases, the Neutral terminal is the root cause; in this case here you can see the neutral has completely melted out of the side of the main switch - I'd wager it was the culprit. Good viewers of TH-cam - please also take this as a salutory lesson; anywhere near a fuseboard is a very, very bad place to be storing flammable junk, coats, etc
The sensible answer is likely that the older ones were too small to accommodate the increase in appliances and load over the last 50 years, and making bigger ones in the same style would "cost too much". So they went with cheaper alternatives and replaced fuses with MCBs to stop people using nails. Not that an idiot can't just keep closing a breaker into a short until the contacts weld together anyway...
Because the stupid people use paper clips for fuse wire as it doesn’t blow so often. Found that “solution” in my old house. Along with melted wire in the voids that still to this day I am unsure how the house had not been burnt down prior to us moving in.
There's nothing wrong with a plastic consumer unit providing the install is done properly. Metal units have only appeared on the domestic scene because of all the dodgy installations that have resulted in fires. Metal consumer units still don't provide the protection they are intended to against fire because there are several glaring design faults.
@@garrett69 Ours has done us well in honestly works exactly as designed and can't fault it, but as you say as long as it is installed correctly it works fine.
Good job Clive... Not sure where you got the original, but I really appreciate the effort you went to in order to share the details. Really: good job. Love your channel!
Love ya stuff Clive. To me the mains stuff is updates. I'm 14th edition and still think of RDDs as ELCBs lol. Not sparked for 20 years but still love electrickery. Once had a petrol station call me out coz their pumps kept going down. So first rule of fault finding, check ya supply. I honestly didn't have a clue about petrol pumps n was winging it. Voltage after the main switch on the CU was about 20 v less than the mains input. The main switch was stuck. Contacts had welded together. This obviously was causing a volt drop and upsetting electronics. New consumer unit, plus a second smaller one to split the loads for the main switches. Sorted.
Some electricians do, especially the ones that show their work on social media, trouble is the UK has had a lot of cowboy electricans for a long time and its going to take a while to get things sorted and done properly.
A ferrule is typically a 0.1-0.2mm thick copper tube with some tin plating. It's not going to do much with strands of that size except split. Now, a proper hydraulic powered tool to flatten and prepare the ends of the tails would be quite useful. It can't be that hard to make an appropriate die set for the usual crimpers of this scale.
@@Monkeh616 You can get ferrules for those gauges of stranded wire, and also for wires many times larger. Some of these needs hydraulic crimping tools to crimp properly. All the strands gets squeezed so much that they take an hexagonal shape to fill out the gap inbetween. I'm fairly sure they will terminate properly, also if the cables are moved around/bend after the cable has been fixed in the terminal. But screwing bare stranded wire into a screw terminal is asking for trouble in the long run. Here in Denmark, I believe all installation cabling for housing/buildings, is done only with solid core wires, that way they don't need to crimp ferrules onto those beforehand.
@@Gin-toki You can get ferrules this size, yes, but I am very unconvinced they will usefully suit a coarse stranded wire such as this - this is actually what is called 'solid stranded' - 7 strands of approximately 2mm diameter solid copper. It seems to me that a simple die to form these into a shape suited to the terminal is a more practical solution than trying to ferrule them (into the wrong shape!). Ferrules, pin crimps, or flattened and ultrasonically welded conductors are already used for any fine stranded cables used by the manufacturers of these CUs.
When terminating incoming tails you're supposed to terminate, adjust bends and re-terminate after the cable has settled. Also after around 5 minutes it's good practice to double check they haven't relaxed and loosened. From what I remember from the video it was the meter tails shorting against the main incoming cpc that blew out the DNO fuse and saved the property. If you look at where and how badly the consumer unit breakers are melted that normally points towards the origin and thermal center of the fire which looks to be potentially dust build up inside the CU around the lighting circuit breakers rather than the incomer. If I was able to inspect it at the time of the fire my suspicions would lye with the B20 breaker on RCD 2 not being terminated correctly.
The more I look back through the original video again the more it seems like the 20 amp breaker failed as everything else during the fire actually tripped out, the main tails shorted out and blew the DNO fuse as confirmed at the start of the video, the reason the main tails aren't in the isolator is purely down to lack of fixings/ rigid consumer unit and cable restraints inside the unit. Thus the fire melted the main incomer as the only thing protecting the main tails was the DNO fuse, the main switch dropped away from the tails due to melting and there's no physical connection other than the plastic main switch holding the incoming tails in position (making it appear the main incomer was at fault).
We had the same problem, but we could see the smoke and removed the fuses, to repair it. The problem are the screws. 1. problem: You screw the cables with the screws and with the neutral rail it is so that you crush the cables when screwing on and even cut them with the screw, this reduces the cross-section of the cable. 2. problem: The force that acts on the cable decreases over time, a professor of mine tested it in the laboratory and wrote a report to the company. If the lines are loaded, current flows over there and the material expands, then the contact pressure increases again, but the material contracts again after the load and thus reduces the contact pressure. If that happens often enough, the contact pressure drops and the contact resistance increases over time. If the contact resistance doubles, then four times the power is released at the contact point. This ensures that the effects are greater again with the next load. Solution: You have to retighten the screws in a fixed interval! Maybe every year, this is fine for the breaker, because there the screws do not have direct contact with the wire. The screws are pressing a plate down on to the wires. For the Neutral rail / Ground-rail, this will cause a problem, because the screw will cut deeper into the cooper or even cut the wire. :-) In my opinion, a better solution for the "neutral rail"-ropblem: The spring clamp technology has the disadvantage that you have to insert the cable into the opening without tension, but the pressure of the cable always remains the same. For example, if you use 6mm² fine strand instead of coarse strand made up of three twisted copper wires, then the problem does not arise. If you use 1.5mm² or 2.5mm² cables, then you just have to make sure that the wires are a little longer to compensate for forces. I use Hager's N-terminal block "KN14N" QuickConnect 14 terminal points. (3 for thick supply cables and 11 for outgoing cables) Price: € 3.21 ~ £ 2.89 www.hager.de/hauptschaltgeraete/anschlusstechnik/pe-n-und-phasenklemmen-quickconnect/kn14n/995507.htm The "KN14E" is the same, but in green/yellow for the ground-rail.
Yes if your from USA then you will be use to having many radial circuits, where as its common to have final ring main circuits (throw back to lack of copper during/after WW2 and then I guess its how we have done it for years and why change now...)
@@oliverer3 UK runs 240v 50Hz Vs "110v USA, North America?". I have watched a few videos from American electrians so I am somewhat versed in the larger consumer/distribution boards over there with the ability to run 110v from both sides of the board (pharses) to get 220/240 for washing machines, dryers garage/shop equipment welders etc.
@@ZanderKaneUK In Germany the boards are also bigger....and actually in my garage I got a bigger sub board than this main board. But the garage extends into a workshop and there's also an EV charger connected to it. My main board has 6 rows, 12 units per row, sub-board for first floor 2 rows with 12 units each. In Germany three-phase is common, even in domestic installations. Standard for a house connection is 3x230/400VAC, 3x63A. So round about 44 kW. Main board: abload.de/img/img_0833hpjjv.jpg Sub-board in the first floor: abload.de/img/img_0834vckc6.jpg In the sub-board are only single phase circuits, but they're equally distributed on the three phases. In most houses here the only three-phase circuit is the kitchen cooker, it's still a 230V appliance but the load is distribuited evenly. Hob is on L1 and L2, on old hobs a big and a small heating plate on one phase. The other two plates on the other one. And the oven supplied by L3. So the kitchen cooker circuit is mostly five core 2.5mm², fused with 3x16A. That's round about 11 kW. abload.de/img/img_0900lwk1v.jpg abload.de/img/img_0898j2jrz.jpg abload.de/img/img_0899pkj7l.jpg
That's about the size (and design) of my consumer unit and it powers a 5 room apartment. My place was built in 2003 so that would have met the regulations back then but my wiring was assembled on a Friday by an apprentice. When I moved in the oven circuit wasn't working and when I unscrewed the power outlet I just found a charred mess where the 'electrician' had clamped down on the insulation instead of the conductor and the circuit had been arcing for 5 years.
In North America, all our breaker panels have always been metal cased with the individual breakers being plastic cased. Our Circuit breaker panels have 200 amps in with 240 volts, then the volts get split by two live rails each at 120 volts, single pole breakers snap into one of the bars, 2 pole breakers snap into both doubling to 240 volts. Typical plug and lights circuits here have 15 amps and 120 volts, Our Central Air Conditioner circuit uses 40 amps at 240 volts.
@@Thriller_Author Another big difference is that you can put in another breaker without turning off the power. Technically you should turn off the power to the whole circuit panel first, but I have never done so.
UK ones have too many wire connections before you get to the breakers. In the US, there's one into the meter socket, one out of the meter socket, and one into the main breaker. That's it. More connections on the higher amperage side, more problems.
@@gantmj Things seem to have got more complicated. For years six plug in re-wirable fuses were deemed adequate. Lights, downstairs sockets, upstairs sockets, cooker, water heater, shower. My two bed house had just four circuits when built.
I honestly think that when we changed to clamping the larger current carrying cables rather than flat screws used in the past, termination overheating has become more common. The termination into a clamp never feels as secure to me. I know it was damage to conductors why the change was made. I used to fit meters some years back and the terminals had two screws in each. I fitted thousands of the things and never had a problem. The termination was always good and I always felt confident that the connection was secure. Also, torque drivers aren’t filling me with much confidence. I know they should be used, the regs tell me but they just don’t feel tight enough.
For how much "better" the UK's power system might be compared to the US, the fact that they ever allowed plastic consumer units compared to the steel electrical panels used in the US seems strange.
We use plastic units here in Brazil, and it's fine. We do however have strict Government testing from INMETRO and regulations called NBR that ensures safety of everything produced and sold. So if it's installed correctly and well dimensioned it never fails.
I have no clue what the UK does but here in Germany the plastic is fire resistant. (At least in the better units) Yes they melt at some point but they will not start burning themselves.
![[UNCUT] The Loyal Pin ปิ่นภักดิ์ EP.15 (3/4)](http://i.ytimg.com/vi/IVwR87OH0_A/mqdefault.jpg)
As a volunteer fire fighter for over two decades I couldn’t watch this video without a lingering sense of that distinct plastic burn smell.
We had an incident a few years ago when our electric storage heaters stopped working. When the electrician investigated, he opened the (metal) box containing the switchgear to find that there had been a fire in it - but it was so well contained that we didn't even smell it. Had the box been made of plastic, I suppose we might not still have a house.
YES, that's why the amendment was made. Even more scary inasmuch that it was storage heaters... you and your family would have been well asleep before the fire started. Glad you had good fortune!
The rest of the world is doing alright with plastic ones 😅
@@IAmThe_RA All metal boxes here in India, used to be wooden in new installations maybe 30 years ago.
American electrician here. I've always been interested in your distribution panels so this was an interesting way to get a first look! We use a similar set up mostly only for motor controls though. One of the first things I learned years ago was ALWAYS double tighten your main lugs at the end of the job! So important, unfortunately some manufacturers seem to be getting so cheap it can cause stripping out of the lug screwhead. Great video, happy holidays.
Absolutely
They do seem to relax with time on occasions.
is rthat a main breaker panel for a house? that looks like something id see in a PLC cabinet for a small machine
@@eldoradoboy that’s the beauty of ring mains rather than radials.
I'm not an electrician, but I am happy to learn some very useful tips. Sometimes something very important like clamping cables. Thank you Clive.
it's often missed by actual electricians too. End of the job for us, on every job, is tighten every screw on the distribution board(s). Even if we've been nowhere near it. Cover Your Arse
Whenever i open a board i always check the screw that holds the incoming active first. I had it jump out on me once when i was pulling a new cable in... not fun. It only takes a second and i have found many loose mains connections over the years.
I love how you still use an isolated screw driver on ... that.
The ends of them give a much better grip than regular screwdrivers. I use mine for putting on cabinet door knobs because they don't slip.
Flat insulated screwdrivers are not flared at the tip and fit nicely into the recessed screws on breakers
Can never be too careful.
Best practices are practiced at all times... get into the habit !!!
@@TheMcspreader Are you asking for a video tour on what he has in his tool boxes?
…and now send it to eBay: "Used and untested"
Slightly discoloured, worked great when last used.
No returns.
Part P quality. Free installation included.
For parts only/not working....... May need attention!
Turn it into a..... Airfix model kit.
It feels weird seeing you describe something I think of as a modern consumer unit as outdated. I'm still in the mindset where having a RCD at all means it's modern as I grew up with those old fuse boxes full of blade fuses people used to repair themselves with fuse wire (or occasionally a 2p piece or a rusty nail).
I've experienced the issue you described about the tails becoming loose after being initially tightened correctly . As a storman for site electrical engineering company I was building a 3 phase 100a mdu and terminated everything and correctly tightened the terminals on the RCD etc . I thereafter decided to manipulate the route the tails took to make everything look neater without going back to check the terminals . Needless to say once the unit was installed on site by a colleague he called to inform me that one of the phases had come out of the RCD and almost gave him a nasty suprise . Lesson learned . As you say its surprising how much the terminals can loosen off if you manipulate the tail after the fact .
Nick has done work for me. Fantastic job. A video from 12 months ago was him rewiring my house. I have learnt a lot from both of your videos. ;) keep smiling keep safe everyone. ;)
Nick is a lovely chap isn't he!
BigClive, recheck your breaker recall paper, it says on it to note the last 4 letters in the sequence
And the breakers appear to say on the side what they are/were. One said B6 above the date code.
@@rkettridge I also noted it, don't think any were in the range though.
Yeah, but none of the visible codes matched.
Interesting. In Canada we have always had metal breaker boxes. Old ones were called fuse boxes when they had the glass twist out fuses.
Clive, please wear gloves when handling burt plastic! In the service we were warned of acid release following the product being exposed to heat of sufficient intensity to cause charing. Some of the acids can permeate the skin and cause health issues years down the line.
Keith
Yeah, hydrochloric acid I believe it is. Nasty stuff.
I think it depends on the plastic, but it's always better safe than sorry. PVC would probably be the one to do that, and this part might be PVC or ABS.
In the auto body repair industry, we were warned over 20 years ago to avoid direct skin contact with plastic body and mechanical components which had been the subject of fire. We were advised of a chemical which was released from some types of burnt plastic which, if got onto the skin, would continue to eat into the skin, and nothing would stop it. The only cure was - AMPUTATION!!!
@@grotekleum "Yeah, hydrochloric acid I believe it is. Nasty stuff." Close, hydroflouric acid. It leaches into the skin and sometimes the only way to stop it is amputation.
Hydrofluoric usually leeches out of burnt synthetic rubber. Nasty stuff for sure!
In the US, "breaker panels", have been steel for as long as I can remember. I'm 62, and have been servicing panels, since I was 16. As for arc fault, or ground fault protection, that's done at the individual breaker level. In case of ground fault, that's mostly done at the outlet, but ground fault breakers are available. Breaker bodies are made of flameproof bakelite, which also does not melt.
For 120V, connect to one breaker, and one neutral. For 240V, connect to two adjacent breakers, as common homes have "split phase", where the phases are alternated at every breaker location (A-B-A-B .... -A-B). In non-industrial commercial locations (ie stores), there usually is 208V/120V 3-phase. 440V/277V 3-phase in large office buildings an small industrial sites.
Bloody hell, when someone in bundy10's comment section said 'send it to bigclive' I thought it was a joke...
I will contest that N.Bundy is very professional especially as he seems to be quite young. Good guy, very knowledgeable.
This video gave me anxiety over the electrical panel at my moms place where I did the distribution board diy style from scratch when I was 15. We moved houses and in the new house there was only the main cutoff and one RCD for the whole two storey house, so I took upon myself to rewire the house as best I could and I installed a box with 20 different breakers and I sorted lights, normal sockets, powerful sockets for dishwasher, clothes washer, electrical boiler, etc. and I ran wires on the walls directly in the neat narrow plastic cunners and the majority of the cables I run inside the hollow baseboards along the floors. That was 7 years ago. When I visit her I always check it. Still works like a charm. I only did that because I was very bonkers on electronics and I had a lamp collection of 3000 lamps by the time I was 15 and I had a powerful variac and used a MOT to demonstrate my friends how electricity makes arcs and blows up fluorescent tubes. I was actually inspired by you Clive, I watched your videos since I was 10.
The wires with the high strand count caught my attention, this reminds me of a connection issue we had in a 200A, 12VDC circuit. The wire involved was made to be very flexible, high strand count, 32AWG strands. The flexibility was required to allow servicing the power converter. The termination crimps on the wire would slowly increase in resistance and heat up. It would often take months of operation for the flaw to get dangerously hot.
It is hard to get a good mechanical connection by compression alone with such fine malleable copper wire.
I have often seen ferrules on the ends of the wires suggested when connecting wires to these sorts of terminations...
"This is fine..."
Of course it is... Not even a power cut happened, it was preventative maintenance.
@@S己G it's a reference to the "this is fine" meme with the dog in a burning house.
tenor.com/view/joke-not-getting-the-joke-flew-over-your-head-stickman-gif-16997031
reminds me of the guy from vice grip garage. "this is fine, we'll just forget we saw that"
just installed a water heater today, the 240v supply coming into the old one, all the insulation on the inner core was cracked on the neutral. some retard wrestled it too much 20 years ago when installed. awful it sat that way that long!
I went to do a job recently at a town house that had had a similar consumer unit fire in its basement. The fire had affected the two floors above and needed new floors afterwards.
My advise is always to fit smoke detectors and suitable fire extinguishers in such areas as these incidents seem to be becoming more common.
I've long admired the well-thought-out lamp / appliance plugs that the UK now uses (as we still use an evolved version of a very, very old design here for our lamps and small appliances), but compared to the heavy, all-metal breaker box on my house here in Arizona, that plastic box looks like a (terrifying) toy! 😲 I'm not an electrician, so I've never personally installed a breaker box (and have no expertise, of course), but I've seen it done here, and every working part of it looked much more heavily built, aside from the housing of the unit, too.
Very interesting! I'll still give points on the UK's fancy lamp plugs, though; very well-engineered.
Finally, an ASMR video of crispy well done breakers. Probably what job security sounds like to an electrician. Should make one of those 8 hr videos to lull electricians off to sleep.
Hahaha
How very true
After doing thermal surveys for nearly 20 years, I’ve found the point at fault is mostly the area with the least debris. (i.e. the hottest point tends to vapourise any insulation near by). In your video the things that pop out for me, are the 2 Neutral cables onto the Neutral busbars, not onto the switch. Also the area were these would be is near the top main cable connections, which is showing burnt insulation, but not vaporised insulation. They also look discoloured & missing the insulation at one end only. It’s only a theory! Keep up the excellent work.
Your way of explaining things is priceless.
"I'd rather pay a bit more and get something decent"
Says the man who buys the cheapest electronics he can find on ebay 😋
There is a difference between stuff you play around with on the work bench and the stuff that goes into your house where your family eats and sleeps.
For mission critical stuff it has to be good quality. The cheapo stuff is for fun.
Just make sure you have an explosion containment device nearby.
@@bigclivedotcom A quality the UK government allowed until 2016. Was not a cheap Chinese import.
@@gorillaau Professional explosion containment piedish
In the US, when I replace breakers or wire up buss bars/panels, I always check the device torque ratings and use a torque wrench. It's usually a 1/2-full turn tighter compared to using a hand screwdriver. I also let it sit for a several days, then recheck all connections. I've found a few that have gotten slightly loose from deformation or temperature variation.
Again Clive, an excellent in detail analysis of a messy outcome!
After seeing this, one wonders why the whole device was constructed from concept in the way it was.
In a catastrophic fault/short/overload event, too much use of moulded parts I feel is not conducive to being robust enough to handle the heat and consequent burn outs which result.
Some manufacturers make a better product than others, very evident when comparing these kind of units.
Great video and talk through, thank you🙂👍
I can smell the burnt parts and soot just by watching clive disassemble the CU.
Same
I cringed through the whole thing. Of "things that could easily include carcinogens", this is one.
the meter/cables are supposed to smell a bit like rotten fish when they begin to melt to alert you to something going wrong. So it probably smelt even worse on fire
Ugh that phenolic resin circuit board stank mixed with the thick PVC insulator goo on that thing!
I'm really glad I can't! That smell gives me nightmares.
Next video: the Consumer autopsy.
Lol.. gasp..you guys kill me 🤪😜👽😂😂⚡
I definitely appreciated the before shot. Didn’t realise at first there was meant to be a whole case around that DIN rail!
1:07 "they went a little bit over the top actually"
says the guy who cooks with 240v AC directly into the food via cut up forks
:p
He was talking about their "safety" measures! ;0)
Do as he says, not as he does. Simple, right?
I recall the name being altered to Firelex in banter over coffee on my 18th edition course
lol i have a nickname for Fed. Pacific Electric panels "Fire Probability Enhanced" with red handles of hellfire
Electro professional for 35 years here. In my opinion, the cause of fire looks like poor contact in connection clamps. Always double check all connections that you tighten with the right torque. And just as important; finally always pull the wire to know that it attaches properly. Several times I have discovered wires that I myself have connected and tightened, and which I can pull straight out of the connection point afterwards😲Always double check. Great video Clive😀
Hi Clive,
I didn't expect that, there is a lot different compared to our panels here in Belgium, we have 2 RCDs to but they ane of 30mA for damp or humid areas (bathrooms and laundry rooms, garden sheds outside lighting)
and a 300mA for the rest of the house and the breakers are all double pole (N and L and a separate ground busbar).
"Earth Bar" sounds like some kind of Hippie granola energy snack.
Or a bar that sells Green organic free range juices and other things equally hippy and a sign that says something like ‘no shoes, no shirt Yes service’ 🤣
Ayy Smokey! Can you tell me who can prevent fires?
It would taste like it too.
@@AgentOrange96 Only you!
Let them eat earth!
if i was a betting man, i’d suspect one of the neutrals from the RCD’s where it terminates in the neutral bars. I’ve seen several of these burn out in electrium consumer units in my 20 years of sparking. a bad design as the cores generally touch the plastic immediately behind the bars, so if they are loose, that heat transfers straight to the plastic. i’ve seen several with big melted holes in the top of the unit due to loose neutrals in the bars, including one that went on fire, albeit not quite as dramatically as the one in this video.
Electrical technician in training here (gettting my certificate in February) this still looks super safe, compared to the things I ran in to already... The old cheramic melting type breakers... With fillament replaced with (at least) 4 mm thick iron nail... Glowing under load. In a woodworker's shop.
In over 30 years of being a qualified spark, I have never seen one of these plastic boards go up in flames ! I have seen them in house fires getting destroyed (but are not the original cause).
The ones in the 1970s and 1980s were made from an entirely different type of plastic closer to Bakelite. The change in the law Clive mentions was after the London Fire Brigade saw a doubling of the number of consumer in about three or four years due to dodgy units like this.
This is the perfect reminder to do my annual inspection of my breaker panels. Most of it I'm not concerned with, just the aluminum service lines, make sure there isn't any corrosion and the lugs are tight.
My ‘new build’ house that was being built around 2008/2009 to be moved into in 2010 has a plastic consumer unit.
*Chuckles* I’m in danger
From what I learned watching Nick and Artisan Electrics, the danger is not so much with the material of the box, but how well the wiring inside it is done.
@@rolfs2165 good to know
@@Alexander_l322 Also the manufacture of the components which were getting stupidity "thin". Which would be fine(ish) if the metals and plastic were of a good enough quality, but if you are making the conector bars to just big enough to cope and are also cheapening the metal mix of the brass, you've taken out most of any redundancy.
It's the date the building was designed that really matters, not the date it was completed.
Great video, being from the USA it's super interesting for me to see how other countries and regions do their power distribution, and learn about the differences and similarities. Thanks!
"They went a bit over the top" I'd rather have something overdesigned than something that they said was "good enough" and have my house burn down.
It is stupid, when the average house price is c £270000 that they make and fit stuff like this. I replaced my consumer unit (back when you were allowed to) in a house thirty years ago and then unit cost much more back then than they do today. Also Kudos to Laing's for fitted a big metal cased 100A switch between the meter and the consumer unit back when they built the house back in 1980.
@@MrDuncl A building inspector once told me: “Don’t do a job much better than a good contractor would - it stands out and raises suspicion that a homeowner with too much knowledge and time on their hands did the job, and it won’t matter that the job may be done perfectly”. I never heeded that advice, though. I’m averse to the specter of electrical fires.
@@MrDuncl
*It was not an equipment failure.* Wylex do make good stuff.
These day it is best to install DP RCBOs with no earth flylead. The price of them is dropping, so now affordable.
I have all my heavy appliances on their own circuit with their own RCBO. All circuits are on RCB's.
Having say the kitchen appliances on their own kitchen ring with mcb's and a RCD, may cause nuisance RCD tripping, with cumulative earth leakage form appliances. That means one appliance the earth leakage is less than 30Ma, so safe - say the w/machine is 20Ma. Then the dishwasher develops a 20Ma leakage, then the kettle does six months later. Have them on all together they are above 30Ma so the RCD trips, with half the house without power.
RCBO's dvide and rule, and are much safer.
@@johnburns4017 I would say it was an equipment failure once the initial fault (which may have been due to poor installation) caused the unit to start burning. That was why the wiring regulations were changed to specify metal enclosures. From a fire safety point of view I would have more confidence in the old Bakelite style Wylex boxes from the 1960s which when tested just smelt and discoloured a bit than this flammable plastic one.
A most excellent exploration!
I also have learned to run the wire, make the bends then terminate them great observations and insight as always Clive.
yes, with UK meter tails (especially the 7 strand type) it pays to bend them first then trim and terminate, people forget the different radii, i've seen so many where 3 out of the 7 strands have missed the main switch!
@@TheChipmunk2008 - I’ve seen an industrial installation when the cable missed the clamp entirely (okay this was a DIN rail fuse holder rather than in a CU) and the installer tightened the clamp past the conductor leaving the cable conductor unsecured and only just touching the terminal. This on the incoming side. When fault finding, I was trying to work out why the voltage kept going when I probed the incoming terminals with the meter, but was steady on the outgoing terminals. But of course, being on a DIN rail, it was moving slightly when I pushed the meter probes on to the relevant terminals... The problem could not be seen directly due to cable trunking.
@@Mark1024MAK omg THAT happens SO often on solid busbars (as used in the UK in distribution boards). So much so that CK and Knipex (I think) both sell 1000v insulated dentist style mirrors to check underneath. Usually an easy diagnosis if the customer complains of a burning smell and the breaker is discoloured even slightly. (takes very little actually discolouring to absolutely STINK), as I'm sure you know.
I sometimes think the method of using stranded cable (NOT 7 strand, which i regard as Solid in larger sizes) as a busbar avoids this, as loose connections are easier to find with a 'tug test'
Yeah, I concur about your opinion about tightening things by hand.
I'm not an electrician, but from a mechanics point of view, there is a time and place when to use a torque wrench, often if you go in heavy handed, especially into aluminium, you risk damaging the the item. So it's best to get a feel with your hand. And only torque as the final measurement.
Indeed, a torque wrench is a good way to shear your bolt head off if you don't know what you're doing.
Very common, we have two in our house. One was installed just before the announcement on changing to metal. So important to check and re-check the tightness on the multi-core connections. Worth getting these tested every few years - like you do for you car.
After you've been through a couple of fires and "knock 'em on the ass" hot mains...you get a whole new respect on power and fire safety.
I don't know much about electronics but I love listening to this guy's voice!
When i learned to wire in germany, we were always told to either use solid wire, or crimp on a wire ferrule...
We were absolutely forbidden fron just clamping down straight, stranded wires.
Over here, any house panel (Or commercial/industrial panel, for that matter) has thick aluminum lugs with concave cuts the wire is pressed into, and Allen (hex) head setscrews. Of course, our smallest wire size for services is #1AWG. 2/0-4/0 more commonly for a home these days, as 100A services are no longer code on dwellings. 150A minimum. Commercial businesses are generally anywhere from 250MCM (kCM) to 750MCM, although they do make wire up to 2000MCM. I can pretty much guarantee you really ain't gonna put a ferrule on those.
But Clive is absolutely right. Bend your wire into the final shape before you place it under the lug. It's hard to believe some dink would do otherwise, and rely on the lug for support during bending. But I guess they have mechanically disinclined retards everywhere.
You should always go over all the circuit breaker terminations several times. You should also check the screws annually because the temperature fluctuations may even loosen them. You can tell if a screw is tight enough, when unscrewing it should be very tight and the screw should make a distinct cracking sound as it comes free.
In the future Clive will be a coroner for robots. "Now let's see. How did this robot die? Ah yes. Now I see. Someone shoved a penny in his fuse holder."
Brilliant 😂😂🤣🤣
@@tinytonymaloney7832 Thanks. Glad it made you smile. Lol. As does Clive with his spudger, and detailed and insightful explanations. Cheers from Canada.
My fuse box recently experienced arcing as a result of a poor connection in one of the fuse bases. For a few years ago our lights would occasionally shimmer sometimes. Over time it got worse, with lights sometimes taking unto a minute to come on, or sometimes turning on a light would cause other lights to extinguish. Eventually our lights switched off one day and we discovered the problem. Luckily our fuse box is made of asbestos, which is both a good and a bad thing...
From experience, the contacts don't look that bad, it's more likely to be loose terminals, i've seen industrial boards where the insulation of the wire has got very hot and melted back, then found the terminal a little loose
Many industrial boards only have one sided din rail (of sorts) with the busbar supporting the other end, in the wylex one end of the busbar is held in the main switch which is fully clipped, the other is in that support, if you need to change a breaker, you don't have to remove the busbar, just undo the screw and slide it up.
I meant to add that i always tried to fully form the bend (preferably without switches or breakers in the way) before cutting and stripping, then you don't get the long strands stopping the cable from being fully inserted ;)
Something like that occured in my back room. My shop was once a laundromat, so Ole Sparky is 7'Tall, 2' deep and 3' wide.... Annual fire dept visit now uses a thermal reader... they found 3 very hot breakers. Elekchicken fixed it same day. Disaster averted.
The redundancy of the safety precautions is incredible... I think the UK has probably the safest electrical standards in the world. I wish we had that kind of redundancy here in the USA. Unfortunately most people only care about the cost of these systems here, so they typically go with the cheapest solutions. They probably don’t realise that a fire caused by electrical failure costs far more than precautionary implementations / devices. When I get a house, I’m definitely going to invest in a UK-style wiring format for my house.
Xmas special where absolutely everything is fed into the vise of knowledge! ( I miss it..)
Things are rather different in the US... :-) What you're calling an isolator I'd call a main breaker. In this old house there wasn't one, but instead a separate box with a couple of huge cartridge fuses in it, rated at 150A I think. Some time back our power got weird, some stuff worked and other stuff didn't. It looked like we had one phase of the two that were coming in off the pole transformer. On contacting the power company we were told that the smart meter was seeing both connectiojns but they sent someone out anyway. It turned out that the weatherhead-meter-ingress stuff had leaked moisture into the fuse box which was in the basement, which caused it to blow. After a while an electrician came out and replaced the whole setup, from the weatherhead on in and including the breaker box, so we now have a main breaker instead of that box and it's all well sealed to keep the weather out of the wiring and we presumably won't have a problem again. I've never seen anything other than metial used for a breaker box, including the one in the house, one in the garage, and a load center in an outbuilding (which I installed). Plastic? No thank you!
It says it is the last four letters of the six letter date code they are referencing. Doesn't look like those are listed. RSRA vs SRRA in the recall.
I'd be more concerned as to how the flame had continued to burn and spread - regardless of a hot spot (arcing fault), you should not get full combustion of the board. It just shouldn't happen. Two possible causes for that amount of damage; 1. lack of (or non-compliant) retardant in the polymers (casing or insulation batch failure), or more unlikely 2. high current thermal runaway on one of the insulated conductors that ran horizontally over the top of the breakers (but why the fuse(s) wouldn't have fused/tripped is another question). I challenge anyone to try and ignite those plastics, especially in an enclosed space with little oxygen, and get them to burn that way.
I'm glad we don't have breaker boxes like this in North America.
Right, there's something reassuring in the chunky old fashion North American breakers. I feel like I could break one of those plastic switches. Also, a metal case just makes sense.
@@bryanhumphreys940 And buss bars instead of manually wiring each breaker / section.
@@bryanhumphreys940 It looks quite identical to the stuff I use in the Netherlands and can tell you that it will be very hard to break such plastic switches ;) . Metal cases are long gone in the Netherlands for standard consumer-units and to be honest, I've never even seen metal-case consumer units, it was either marble as a baseplate with bare connections and switches, than came porselain, eventually bakelite and then just, well, plastic (don't know what kind of plastic, but I think PC).
Industrial boards used to have bare wires and connections on marble baseplates before porcelain. Than metal enclosures for long, until glassfibre reinforced stuff hit the market. Bakelite was used as well, but metal was usually preferred.
@@madmanmapper It depends. ABB's bussbar-system is becoming more common, but replacing just 1 breaker in a panel can be a pain in the ass, as, just like this UK consumer unit, the DIN-rail click-on stuff is rather standard.
@@weeardguy Maybe check out some American units to see what I'm talking about. They are pretty robust and simple to work with.
My work uses those kinds of breakers all the time in industrial control panels.
Neat to see them being used in residential in the UK.
Here in the US residential breakers .... basically do whatever the crap they want, with each manufacturer using a completely different (not to mention completely incompatible and varying levels of unsafe behind the control panel) system to install and power the individual breakers.
Oh yeah in my partners old flat someone had done some illegal wiring to splt the building into two flats, moved the electric meter and installed a second one. We noticed smoke in her flat if the shower and the oven were run at the same time, I did some poking about and noticed some charred wood behind the two tails as they came out the meter and into the consumer unit.
An electrician came out (eventually, the landlord's solution was "don't cook and shower then..."), they said "I'm not allowed to touch that bit, you need the electricity board", they turned up and said "who the F*ck installed this?". Turns out the tails were arcing between themselves as the insulation had failed.
Thats not the only Problem...
Seems like the fuses are to high for the small cables.
Otherwise the circuit breaker (fuse) should have tripped
@@NinoJoel If the arc is drawing less current than the fuse's rating then there's no reason for the fuse to blow.
@@eDoc2020 it would not have arced if the isolation was fine...
I know it often won't trip the breaker but the breaker should have tripped way before it started arcing.
Wy? Simple.....
I think the combination of electric heated water and the high current from the oven combined overloaded the cables and melted the isolation to the point it started arcing.
We rented a static caravan in which there was a big switch to actually stop you using the shower and the cooker at the same time. I don't know which country you are in but what is the point of installing an electricity meter if the electricity board doesn't know it is there ?
@@MrDuncl what do you mean?
If you hook up a second electricity meter behind a electrical distribution board you can see how much electricity the second board used.
You just have to read the main electricity meter and remove the summ that the second unit counted.
Not that I'd *ever* make fun of what looks to be a horrible event for someone else; looking at the linked vid, it seems no one was injured, and the fire was very well contained -- both amazing, IMO. But I do feel vindicated for long questioning the quality and wisdom of implementing those plastic mains distro enclosures, often met with "I've never had a problem." I always wondered what happens if the metal gets hot and the plastic melts. Well...now we know. Thanks for the crispy 'n crunchy autopsy, Clive!
I am amazed they allow plastic distribution panels. In the US, everything has been metal for a long time.
My house (I'm in uk) still has a black plastic box from the 1960s, with Wylex fuses.
The incoming mains is tarred cloth and has served the house since 1931, probably. I also got some VIR wiring in the house too.
I know its historical but I think Wylex wired fuses are still a BS standard.
The US also didn't experience as much of a copper/steel shortage during WWII.
Agree, I don't think US mains panels have ever been anything but steel. That said, plastic is the material of choice in residential outlet and switch boxes.
@@ec8107 when I was in the states I remember the fuse holders being made of glass,like a round cylinder and a grey metal box.
I was in Alabama so I'm not sure if regulations change from state to state.
I don't miss window AC though!!
@@wesleymays1931 not int he same way, but we did try using aluminum wire for a while in the 70's. Also, the Federal Pacific breaker panels that would weld themselves closed and to the bus bars, only recalled mains panel in US history
Had to replace a Shower pump years ago, changed it it wouldn’t work. Checked the supply Reverse polarity Everywhere... called the board.. shut the house down. Turned out a car 10 years prior hit a lamp post outside very close to incoming supply to house. Guy who cut the cable outside switched em round never checked inside the house 🤦♂️💥 was like that for 8 years. Interstellar video Clive.
Plastic enclosure, brown and blue wires, horizontal breakers? It’s all so strange!
we use vertical rows too, but not in small domestic installs. Ring mains mean 1 or 2 breakers for the entire flat/apartment intead of (much safer) radials to each set of outlets
(Ring mans had a purpose in the 1950s when there was a copper shortage, They should have been outlawed by the 1970s regardless of fused plugs. Radially wired houses are perfectly safe and legal in the UK with a big advantage that losing one breaker DOESN'T result in losing half the house)
Brown,black and grey are the phase colour's in the EU.
Blue is the neutral and green/yellow is earth.
The horizontal breakers are Standard in most of the installations in the EU.
Where the differences come in is that in Germany for example we have 3phase power to each house and load balance manually and create a local "star point" (i don't know the proper translation)
In France it's mostly the same but better sockets then the German "Schuko" , in the UK they only have one phase for a average home that needs to carry some huge current and this is a design that asking for trouble in my opinion.
And the ring main is antiquated and needs to go.
It keep the consumer unit small but it keeps causing problems and is a pain to install.
Sooty indeed! Never seen one that cremated before. I have an almost identical Marbo branded unit. Same company I think.
Here's my diagnosis based on the evidence presented.
We have a L+N supply to the top of the isolator. from there we have 2 L+N unfused going to the RCDs. There is one pair of these that are completely devoid of insulation and I'm suspecting it was the pair to the RH RCD. I suspect the fault has been with these wires as clearly, they've been the hottest. That means there has been nothing inside the CU to protect against a fault at that point and being close to the main supply wires, has damaged those too. So, of the suspect pair, I'm guessing a strand or two from L or N has been free of the terminal to link across to the other creating a dead short. Quite possibly strands of N linking across to L.
On that basis, a Wylex manufacturing fault in failing to install all the strands into the terminals feeding the RH RCD. OR for whatever reason, the local sparky had removed those wires for some reason and refitted them badly/incompletely.
I don't see any evidence of a fault in any component therein.
This is why I check my circuit breaker box from time to time in my basement, especially when I run high amperage devices like electric heaters. One time a wire had become oxidized from age and lost proper contact in my box. The side of my box became so hot even when running something of rather low power consumption like a fan, that the insulation on the wire and some plastic holding clips on the common junction started to melt! This could have been a major disaster! This also happened in my sister's house and she has the infamously dangerous aluminum wiring. I tell people to once in a while check your circuit box, especially if you have an old home! You may be glad you did! 👍👍
13:21 there's the rating dot-matrixed onto the side of the breakers... B32 on the clump then the next ones are B6...
And the last four letters on the B6 are RSRA, which is not on the list.
The breakers seem to all be clearly labeled just above the input screw on the front.
Nick has one of the best channels on TH-cam, as do you. I love when my geeky worlds collide.
I always get my tails bent into place, then slightly untwist and flatten the end with pliers, torque it up, quick side to side wiggle, torque it again
@bigclivedotcom Clive, I don't fully understand electronic mate, so on the Wylex board, the non-burnt one you showed, what is the purpose of the two yellow buttons on the RCD slots? And what is a RCD and it's purpose? lol
An RCD or GFCI compares the current going out to the current returning. If they are significantly different due to a fault or someone receiving a shock, it turns off the power.
That pre-wired consumer unit surprises me as a Kiwi. Here we're limited to three circuits per RCD, whereas you have five on that board. You also switch the supply neutral which begs the question - how does UK grounding work? Here in NZ our neutrals are tied to ground potential at several points in the distribution network, as well as inside the distribution board (via MEN link). We usually have the incoming neutral going to a bar, and from there supplying our RCDs, as well as linking to the ground bar. Are your neutrals grounded prior to the consumer unit?
It's fairly common to see all the circuits for a house on a single RCD in the UK in older consumer units that have RCD protection, though the regulations don't permit that now. Our neutrals are often connected to earth at several points along the distributors supply network (PME) but neutral and earth must kept separate in consumers installations. The neutral is switched as it is common for the electricity supplier to not provide any earth connection or the neutral is only connected to earth at the transformer so the neutral might not be at 0V to earth on some supply arrangements.
Yes like Echo says, it's quite common to see everything on a single RCD, or even more common to see RCDs on sockets but not on lights. And yes, the neutrals are grounded throughout the network if PME*
PME is similar to MEN, with the difference that the link is on the supplier's side, rather than the customer's side. (the link is in the service head with the main fuse, not in the consumer's DB) . Both are subtle variants of TN-C-S. The reason for opening the neutral is (in my guess) twofold: 1, the historical use of RCD's as main switches,. and 2, the fact that neutral is considered a 'live' wire under the 18th edition of the wiring regs
*ALLEGEDLY
What a great argument for metal consumer units and fire seal
I have one of these! However, I do inspect it quite regularly, and give it a good health check before winter sets in. I have admit though, that's a sobering sight on your bench.
There's a reason the wiring regs now insist on metal consumer units.
I have a contactor that has done something similar thought not to the same degree. The cause: 65yo engineer inserted 8AWG(I think), it should have ben 6AWG along the screw that applied pressure to the clamp. Tightened the clamp and it drew the cable into the screw slightly but did not successfully clamp the cable. That was a fun repair. Contactor was part of/installed inside a Heller reflow oven. I still have it if you would like some pics. I considered sending it to you but the shipping would be horrendous. Timeframe was conveniently right when you did your video tearing down a very similar contactor like within days. We moved our factory in the middle of that repair and I think there a few missing pieces to the old contactor but you can get the gist of what was going on. I may even have some old photos taken on my back of the burned unit still installed inside the machine and some of the cable damage.
Late watching this but the one before was AVE putting Metal Plates into a bucket of brine as a load tester and watching for minutes on end drawing 24Amps through a 20Amp breaker waiting it to trip. I'll link this for him.. Chuckle... (Edit, you beat me to it in his comments!)
I also watched that AvE video, earlier today. Safety was (by his own admission) definitely job #3 as he gave that Tailgator a hot supper.
Adds a whole new meaning to electric barbeque's. Thanks for the tear down.
Damn, my last comment didn't post properly. I'll try again. I don't think the source of the fire was the isolator contacts, they are far too clean, I would also expect the plastic parts that actuate them to be melted, they are not even brown.
The RCD to the left of the isolator is also almost undamaged, though the most of the melting seems to be on the neutral side at the right of the isolator. Most major contact heating I have seen also damaged the adjacent module.
I have seen main switches by Hager, MK and CGD with contact faults, the inside of the switches were all badly burned where as the screw terminals and outer casings were largely undamaged. I'll try and dig out the photos.
Could it be possible the fire started at the top of the consumer unit at one of the neutral bars, perhaps the right hand one? I have seen lots of thermal damage in consumer units from failed contacts and terminals, but I've only seen fires (2 of them) from poor connections at neutral bars setting fire to the not so heat resistant enclosures the bars are directly in contact with.
I have a burnt connection here I took out of a 100A MEM Exel switchfuse, the 35mm2 cable was poorly installed. The copper is fairly clean where it was inside the terminal, despite the heating, above the terminal it is very green. One of the strands has erroded away from the arcing, some of the others have little pits melted in them where arcing has occurred. The PVC is rock solid. imgur.com/a/3SlFClL
That's my thoughts and experiences from the last 17 or so years anyway!
yep with you 100% on it being a loose neutral. The fact that the fire started at the top and worked its way down amplifies that
A lot of 'electricians' also think of the 'neutral bar' as less important because "it's not live, right?" so they check for tightness at the breakers, and tails, but ignore the neutral bar
I despair at that mode of 'thought'.
Never really thought about it before now, but all the breaker boxes I've ever seen in person (here in California) were indeed metal. On the one hand, I'm a bit surprised they never tried plastic, but on the other, this video.
I bet John Ward is loving this video.
It's weird because I came here from a John Ward video lol
...... He would be saving it for Xmas night !
My consumer unit is in my porch which looking at that mess is probably a good thing, even if it is directly in a main exit from the building. Although this is a new house built in 2018 so the consumer unit is a metal box, and there's also an isolator switch between the main fuse and the entire consumer unit next to the meter outside.
It's certainly an improvement from the old bakelite Wylex fusebox in my old house that had the ancient wire-wound cartridges and was right next to the gas meter, in the cellar, about two inches from the ceiling...
"Dont worry if you still have one of these"
*looks at his old bakelite fuse box*
This is fine.
The breaker box where I live was last inspected in 1976. That's when the house was built. No fires yet, but...
Well at least bakelite can't melt. It's probably way safer than this plastic crap.
Bakelite just chars lightly and smells fishy, much safer than later plastics...
@@tyttuut I think mine is of a similar era, has an old electrical board sticker on it who have been defunct since the early 80s.
You can smell the old bakelite boards overheating. But they're generally made to a higher standard anyway.
Interesting vid and post mortem - I can almost smell the foul fish-like stench of burnt fuseboard through the screen.... You've a new subscriber :)
As an electrician, I've seen my fair share of burnt out MCBs and Main Switches - as a general rule tho, very few reach this stage of destruction. In most cases, its caused by a poor connection (either not tight enough caused by overheating or human error during installation) or poor environmental conditions causing corrosion and tarnish in the terminals, which in turn overheat, tarnish further, overheat more.... you get where this leads. In most Main switch cases, the insulative barrier between the live and neutral terminal breaks down first, causing contacts to meet and a dead short that trips the main isolator itself or takes the DNO fuse. This time it didnt happen and things got serious :(
In a majority of cases, the Neutral terminal is the root cause; in this case here you can see the neutral has completely melted out of the side of the main switch - I'd wager it was the culprit.
Good viewers of TH-cam - please also take this as a salutory lesson; anywhere near a fuseboard is a very, very bad place to be storing flammable junk, coats, etc
I still remember the old cast iron and pottery consumer units, with real fuses with wire fuses. What did we rip them all out for ?
I was going to say similar, didn't have that problem with those.
Oh yeah. I cut my teeth on those in the 50’s/60s!
The sensible answer is likely that the older ones were too small to accommodate the increase in appliances and load over the last 50 years, and making bigger ones in the same style would "cost too much". So they went with cheaper alternatives and replaced fuses with MCBs to stop people using nails. Not that an idiot can't just keep closing a breaker into a short until the contacts weld together anyway...
Because the stupid people use paper clips for fuse wire as it doesn’t blow so often. Found that “solution” in my old house. Along with melted wire in the voids that still to this day I am unsure how the house had not been burnt down prior to us moving in.
@@pkf4124 Ugh. And you just know if you showed those people the damaged wiring, all they'd say is "It still works, don't it?"
Brought here by Nicks video and I’ve just ordered a torque driver.
Never even thought about right not being right.
Well that beginning didn't fill me with confidence, we have had that since 2007 when the kitchen got redone after the floods....
There's nothing wrong with a plastic consumer unit providing the install is done properly. Metal units have only appeared on the domestic scene because of all the dodgy installations that have resulted in fires. Metal consumer units still don't provide the protection they are intended to against fire because there are several glaring design faults.
@@garrett69 Ours has done us well in honestly works exactly as designed and can't fault it, but as you say as long as it is installed correctly it works fine.
Good job Clive... Not sure where you got the original, but I really appreciate the effort you went to in order to share the details. Really: good job. Love your channel!
*_Crispy._*
Love ya stuff Clive. To me the mains stuff is updates. I'm 14th edition and still think of RDDs as ELCBs lol. Not sparked for 20 years but still love electrickery.
Once had a petrol station call me out coz their pumps kept going down.
So first rule of fault finding, check ya supply. I honestly didn't have a clue about petrol pumps n was winging it. Voltage after the main switch on the CU was about 20 v less than the mains input. The main switch was stuck. Contacts had welded together. This obviously was causing a volt drop and upsetting electronics.
New consumer unit, plus a second smaller one to split the loads for the main switches. Sorted.
Would it not be an idea to use ferrules on those cables when they are multicore to ensure better connection?
To my knowledge here in Belgium it is obligatory unless using specially rated terminals. But for simple screw terminals you must.
Some electricians do, especially the ones that show their work on social media, trouble is the UK has had a lot of cowboy electricans for a long time and its going to take a while to get things sorted and done properly.
A ferrule is typically a 0.1-0.2mm thick copper tube with some tin plating. It's not going to do much with strands of that size except split.
Now, a proper hydraulic powered tool to flatten and prepare the ends of the tails would be quite useful. It can't be that hard to make an appropriate die set for the usual crimpers of this scale.
@@Monkeh616 You can get ferrules for those gauges of stranded wire, and also for wires many times larger. Some of these needs hydraulic crimping tools to crimp properly. All the strands gets squeezed so much that they take an hexagonal shape to fill out the gap inbetween. I'm fairly sure they will terminate properly, also if the cables are moved around/bend after the cable has been fixed in the terminal.
But screwing bare stranded wire into a screw terminal is asking for trouble in the long run.
Here in Denmark, I believe all installation cabling for housing/buildings, is done only with solid core wires, that way they don't need to crimp ferrules onto those beforehand.
@@Gin-toki You can get ferrules this size, yes, but I am very unconvinced they will usefully suit a coarse stranded wire such as this - this is actually what is called 'solid stranded' - 7 strands of approximately 2mm diameter solid copper. It seems to me that a simple die to form these into a shape suited to the terminal is a more practical solution than trying to ferrule them (into the wrong shape!). Ferrules, pin crimps, or flattened and ultrasonically welded conductors are already used for any fine stranded cables used by the manufacturers of these CUs.
When terminating incoming tails you're supposed to terminate, adjust bends and re-terminate after the cable has settled. Also after around 5 minutes it's good practice to double check they haven't relaxed and loosened. From what I remember from the video it was the meter tails shorting against the main incoming cpc that blew out the DNO fuse and saved the property.
If you look at where and how badly the consumer unit breakers are melted that normally points towards the origin and thermal center of the fire which looks to be potentially dust build up inside the CU around the lighting circuit breakers rather than the incomer. If I was able to inspect it at the time of the fire my suspicions would lye with the B20 breaker on RCD 2 not being terminated correctly.
The more I look back through the original video again the more it seems like the 20 amp breaker failed as everything else during the fire actually tripped out, the main tails shorted out and blew the DNO fuse as confirmed at the start of the video, the reason the main tails aren't in the isolator is purely down to lack of fixings/ rigid consumer unit and cable restraints inside the unit. Thus the fire melted the main incomer as the only thing protecting the main tails was the DNO fuse, the main switch dropped away from the tails due to melting and there's no physical connection other than the plastic main switch holding the incoming tails in position (making it appear the main incomer was at fault).
That happens when you have 4 or more stoves cooking crack at once ,,, so I’m led to believe,,wouldn’t really know myself,,,
We had the same problem, but we could see the smoke and removed the fuses, to repair it.
The problem are the screws.
1. problem:
You screw the cables with the screws and with the neutral rail it is so that you crush the cables when screwing on and even cut them with the screw, this reduces the cross-section of the cable.
2. problem:
The force that acts on the cable decreases over time, a professor of mine tested it in the laboratory and wrote a report to the company.
If the lines are loaded, current flows over there and the material expands, then the contact pressure increases again, but the material contracts again after the load and thus reduces the contact pressure.
If that happens often enough, the contact pressure drops and the contact resistance increases over time.
If the contact resistance doubles, then four times the power is released at the contact point. This ensures that the effects are greater again with the next load.
Solution:
You have to retighten the screws in a fixed interval! Maybe every year, this is fine for the breaker, because there the screws do not have direct contact with the wire. The screws are pressing a plate down on to the wires.
For the Neutral rail / Ground-rail, this will cause a problem, because the screw will cut deeper into the cooper or even cut the wire.
:-)
In my opinion, a better solution for the "neutral rail"-ropblem:
The spring clamp technology has the disadvantage that you have to insert the cable into the opening without tension, but the pressure of the cable always remains the same.
For example, if you use 6mm² fine strand instead of coarse strand made up of three twisted copper wires, then the problem does not arise.
If you use 1.5mm² or 2.5mm² cables, then you just have to make sure that the wires are a little longer to compensate for forces.
I use Hager's N-terminal block "KN14N" QuickConnect 14 terminal points. (3 for thick supply cables and 11 for outgoing cables) Price: € 3.21 ~ £ 2.89
www.hager.de/hauptschaltgeraete/anschlusstechnik/pe-n-und-phasenklemmen-quickconnect/kn14n/995507.htm
The "KN14E" is the same, but in green/yellow for the ground-rail.
Hmmmm exposed conductors on the line and neutral coming out of the main switch on the new Wylex.....
I think you're spot on with loose connections. I would believe the cable overheated and lit the insulation then the rest was a cascading failure.
Are you saying that you all use that unit to power a whole house? I doesn't seem big enough to power my garage.
Do you run on 120V or 240V?
Yes if your from USA then you will be use to having many radial circuits, where as its common to have final ring main circuits (throw back to lack of copper during/after WW2 and then I guess its how we have done it for years and why change now...)
@@oliverer3 UK runs 240v 50Hz Vs "110v USA, North America?". I have watched a few videos from American electrians so I am somewhat versed in the larger consumer/distribution boards over there with the ability to run 110v from both sides of the board (pharses) to get 220/240 for washing machines, dryers garage/shop equipment welders etc.
@@ZanderKaneUK In Germany the boards are also bigger....and actually in my garage I got a bigger sub board than this main board. But the garage extends into a workshop and there's also an EV charger connected to it. My main board has 6 rows, 12 units per row, sub-board for first floor 2 rows with 12 units each. In Germany three-phase is common, even in domestic installations. Standard for a house connection is 3x230/400VAC, 3x63A. So round about 44 kW.
Main board:
abload.de/img/img_0833hpjjv.jpg
Sub-board in the first floor:
abload.de/img/img_0834vckc6.jpg
In the sub-board are only single phase circuits, but they're equally distributed on the three phases. In most houses here the only three-phase circuit is the kitchen cooker, it's still a 230V appliance but the load is distribuited evenly. Hob is on L1 and L2, on old hobs a big and a small heating plate on one phase. The other two plates on the other one. And the oven supplied by L3. So the kitchen cooker circuit is mostly five core 2.5mm², fused with 3x16A. That's round about 11 kW.
abload.de/img/img_0900lwk1v.jpg
abload.de/img/img_0898j2jrz.jpg
abload.de/img/img_0899pkj7l.jpg
That's about the size (and design) of my consumer unit and it powers a 5 room apartment. My place was built in 2003 so that would have met the regulations back then but my wiring was assembled on a Friday by an apprentice. When I moved in the oven circuit wasn't working and when I unscrewed the power outlet I just found a charred mess where the 'electrician' had clamped down on the insulation instead of the conductor and the circuit had been arcing for 5 years.
In North America, all our breaker panels have always been metal cased with the individual breakers being plastic cased. Our Circuit breaker panels have 200 amps in with 240 volts, then the volts get split by two live rails each at 120 volts, single pole breakers snap into one of the bars, 2 pole breakers snap into both doubling to 240 volts. Typical plug and lights circuits here have 15 amps and 120 volts, Our Central Air Conditioner circuit uses 40 amps at 240 volts.
Very different from USA breaker panels
One big difference is the far fewer circuit breakers in the UK one
@@Thriller_Author Another big difference is that you can put in another breaker without turning off the power.
Technically you should turn off the power to the whole circuit panel first, but I have never done so.
Yeah we stopped feeding houses with 4awg wire many years ago lol
UK ones have too many wire connections before you get to the breakers.
In the US, there's one into the meter socket, one out of the meter socket, and one into the main breaker. That's it.
More connections on the higher amperage side, more problems.
@@gantmj Things seem to have got more complicated. For years six plug in re-wirable fuses were deemed adequate. Lights, downstairs sockets, upstairs sockets, cooker, water heater, shower. My two bed house had just four circuits when built.
I honestly think that when we changed to clamping the larger current carrying cables rather than flat screws used in the past, termination overheating has become more common. The termination into a clamp never feels as secure to me. I know it was damage to conductors why the change was made.
I used to fit meters some years back and the terminals had two screws in each. I fitted thousands of the things and never had a problem. The termination was always good and I always felt confident that the connection was secure.
Also, torque drivers aren’t filling me with much confidence. I know they should be used, the regs tell me but they just don’t feel tight enough.
For how much "better" the UK's power system might be compared to the US, the fact that they ever allowed plastic consumer units compared to the steel electrical panels used in the US seems strange.
They thought it'd lessen electric shocks that people got from steel boards. Pre RCDs.
We use plastic units here in Brazil, and it's fine. We do however have strict Government testing from INMETRO and regulations called NBR that ensures safety of everything produced and sold. So if it's installed correctly and well dimensioned it never fails.
I have no clue what the UK does but here in Germany the plastic is fire resistant.
(At least in the better units)
Yes they melt at some point but they will not start burning themselves.
Plastic or not, a fire in a fusebox/consumer unit isn't good either way
@@NinoJoel Before plastic, everybody used wooden consumer units except for big industrial setups that were either marble or enclosed steel.
I watched the Nick Bundy video where he replaced this
I like the way it’s carried on to here, to be inspected