EICR FAIL- Maximum demand
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- เผยแพร่เมื่อ 7 มี.ค. 2019
- An off the cuff on-site vid where I look at how maximum demand has played its part in this installation failing its condition report.
Warning: Contains no humour or strong language. Sorry, but I was on a customer site!
*Correction* At 12:09 I say the SWA has used "brown for neutral", I did of course mean 'black'.
There's a whole shopping list of problems at this site, but only a few are mentioned here, so don't yell at me if you spot something I don't mention on camera as it was the maximum demand I wanted to talk about in this vid!
A follow up video was posted 03 August 2019:
• EICR failure site - ri... - วิทยาศาสตร์และเทคโนโลยี
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Never have I watched a video of a spark whom is so well spoken and informative. This is a cracking vid mate. You've earned yourself a subscriber. This comes from a fellow spark :)
Very kind of you to say so sir.
Ha, ha, ha... watch a few more videos from DS and you may have to edit the bit about being 'well spoken'!! Isn't that right, Dave?
All joking aside though, I watch a lot of your vids David and consider your opinion to hold a great deal of sway.
Your knowledge, together with your industry ethics, is essential viewing in my opinion. Plus, your banter makes for great viewing entertainment!!
As an ex emeb / cn / wpd mains engineer I'd be very surprised indeed if the one amp is actually leakage current from a phase conductor unless there's a solid fault to unbonded metalwork that has an impedance of circa 240 ohms 'within the ground' and the nigh on 0.25kW of heat energy is dissipated into mother earth, or a phase conductor is touching damp brickwork etc. (possibly via unnbonded metalwork) and the heat is being absorbed by the building structure. I've had both of these situations to sort out when customers were getting shocks when outside their property because of the potential gradient across sections of brickwork and across the surface of the ground. I mention heat absorption because circa 240W of power loss at one 'point' location would be most likely to quickly raise the temperature to a level where a fire would result. It's perhaps more likely that the problem is a neutral to earth fault within the property, the 1A of current in the main earth connection to the lead sheath of the service cable being some proportion of the neutral current of the whole installation because there wil be a tendency for the neutral bar to be at a slightly higher potential than the earth connection of the 'tns' type supply at this property - hence all of the instalation neutral current will be 'attracted' to some degree to flow from the neutral bar, along the neutral of the faulty circuit and via the fault into the cpc or bonded metalwork etc, back to the main earth bar in the consumer unit and then via the main earth lead to the lead sheath of the service cable....which will (should!) have an almost zero impedance link back to the supply transformer neutral point. The crossed colours on the armoured cable also has me wondering - is the neutral of that circuit actually connected to the earth bar of the consumer unit and the cpc conected to the neutral bar? - that would also explain what's happening - the 1A would be the neutral current from the load of that circuit!
That, everyone, is the voice of experience and wisdom. I hope this person teaches sparkys how to wire things up. There are a lot of crap ideas in the regulations, and a lot of good ways of doing things which aren't in the regulations, too. I get the impression this engineer knows the ins and outs of both these situations.
This is also needs to be taught to all jointers/linesman who havent got a clue what ohms law is
Tip: Instead of taking your earth leakage from the earth cable (which could potentially include currents from other properties) put your clamp meter around the two tails and you will get a true reading of the leakage from the installation - ie the difference between the current in and the current out.
I blimin love your videos!! you have a unique and addictive channel." I love how you go through the fault testing side in such detail" ! it's a channel that stands out from the rest on here....Thank you..
Thanks Russel, very kid of you to say so.
What do you charge per circuit if you don't mind me asking. I've been caught out a few times with a small dwelling that has several circuits. 👍
From my experience that cut out is a 60 amp version. Even then it takes a long period of time to blow on overloads such as it is . As for the split ring main I use a signal generator to trace the runs . Can be very good for finding cpc and other breaks too . Great to watch
That was a very interesting video David. I did years of testing many moons ago and it can be very taxing and tricky. Well done on spotting all the faults. It’s not easy, especially when you’ve got heaps of extensions, additions and alterations galore. I agree, R.C.B.O.s throughout. That’s my basic choice these days. It would be good to see a metal clad fire proof board in there. I hope you get the work, I think you’ll do a nice neat and tidy job of it. I hope you do a video of the shower switch you mentioned. That sounds very interesting. I don’t know about them? Thanks again for the video David. Have a good weekend!
Thanks David, I might see if I can push out that shower priority board video tomorrow (hangover pending).
Very interesting, especially the ramifications as to potential disastrous failures and the widespread remedial work needed. Headaches - big ones for the new owner.
I do EICRs most days good to see someone posting videos about the daily rubbish we see. Keep up the good work!
Thank you for that compliment
Excellent video David, amazing what you find! Thanks for sharing.
I found a can of Guinness in this case!
And this is the best reason I have ever seen for EICRs. It often seems like a pointless paperwork exercise, but then you find this mess.
Excellent and informative stuff DSES!! Keep it coming please.
Another great video. Nice to see a video of you out on site. Look forward to seeing the device for shower load. Thanks for sharing.
Nice to see someone working properly
Really interesting and informative video, thanks for a great Chanel David.
Excellent, as always. If I did not live in the boondocks in Ireland, every job would go to you and Nigel.
Albert.
Thanks Albert!
I purchased a 5 bedroom villa with pool in Thailand.
When any of the 3 instantaneous water heaters are used, the lights go dim.
The voltage at KWH falls from 220V to 200V.
Luckily KWH is in the garden in a box with my neighbor"s and get to make an actual ring main when I do repair.
They have same size cables and under voltage problem on our private estate.
KWH are for from private distribution board.
David great video, as a learner this give me a good inside what you come across these discrepancies when doing a test 👍
That's a fishy comment....
@@simonmaverick9201 What a comedian!
I’m not surprised that the incoming cable has overheated! It was probably originally serving a 3 bed house with maybe an electric cooker and an immersion heater plus a few sockets and lights
Really interesting mate 👌great content as always, really enjoy your chanel keep up the good work
'Exciting' be blowed! This video is fascinating. Cheers David.
The ones I think are really boring and waffle-filled always seem to do better than those I've spent a wodge of time and effort on!
Hi Dave great video. I came back and watched this video after testing a single dwelling with over 30 circuits... If you don't mind me asking, what was the outcome in the end..?
Good video mate. Would be good to do a follow up to this video with the new DB and investigate the earth leakage source.
Was thinking the same. Might be a while before it's all done and dusted at that site, although I think we'll get the work.
I agree, the final outcome would be interesting!
@@dsesuk I hope you do. Would be nice to see them get a proper installation instead of the mess they currently have. Edit: Actually, I see this is an older video. Did you get the job?
@@floorpizza8074 Yes, we've been appointed for the work, but the new board still hasn't gone in. We've since been back for some remedial work to allow the upgrade to go ahead, but the delay is down to scheduling and to our waiting for some new consumer unit models to come out as manufacturers switch from type AC to type A RCBO's. We should hopefully be doing the board change in the next couple of weeks.
@@dsesuk Good to hear! Love it when guys that do high quality work (and take great pride in it) get the job. I know you're really busy, but would love to see a bit of video from that job. :)
Great video. Helps to see someone else carry out an EICR and how you investigate
Great video thanks David! Seen exactly the shower thing a couple of times now with multiple en-suite hmo conversions.
The subject needs more attention to it, especially on the generally terrible EICR form, would love to see how you tackled detailing this on the cert.
Hi Andrew. It is an awful form, I quite agree! The failed RCD I've coded as a C2 in item 4.8 (manual operation of circuit breakers and RCD's) because it won't react in the event of a leakage fault, and as a C1 in item 4.19 (RCD's provided for additional protection) as it's handling more current than it was designed for, so all bets are off as to how it will react. The failed RCD also shows up elsewhere on the checklist of course (items 5.12.1, 5.12.3, 5.12.5 and 6.1). As the demand of the installation is potentially more than the service head should be handling, I've put that as a C3 in item 1.2. It could perhaps be argued that a C1 or C2 applies, but it's been coping for the past fifteen years, and besides the common sight of the tarry insulation having leaked out, there's no outward evidence of it being unable to cope. We have an enquiry in with WPD about replacing the head to 100A PME with an isolator, and we have the go-ahead for a board change. One of the showers will be decommissioned as they're turning that bathroom into a utility room, so that should help the situation!
Thanks for the detail David. Ar the difficulties of trying to express a problem with something that’s apparently been fine for an age, but good call on the service head item i feel.
I would have probably gone with just C2s for the rcd but can’t fault you!
At least it seems your client is interested in getting it improved, that’s 90% of the battle in my experience, and if you’re board changing with 2 showers you can get the rcd load sorted even if they don’t want to spring for rcbo’s.
Not a bad result at all.
Top notch work as always mate!
Earth current is probably from another property with a failed CNE. You should clamp the two live conductors at the same time to determine the origin of the fault
Was the previous spark playing "pin the tail on the donkey" when wiring the extension?
Having looked again at the video, david says that it isn't a simple case of 'crossed cores' on the armoured cable, (and the circuit appears to be rcbo protected) so l hope he gets the job of sorting out why there's an amp of current in the earth lead and lets us know the answer...RL.
Hi David, Second time watching this one. Really good advice.
One observation, I think you should not be confident applying the correct cost for the jobs you offer to do.
Professional advice and honest evaluation is a commodity which must have a higher value than a rushed cheap fix which will not stand the test of time.
The people buying this place will have a couple of grand to protect their investment, I would assume.
Get your bill in, and don't miss them for time spent saving their new home from burning to the ground.
Interesting video, thanks. It reminds me of an installation I was slightly involved in (I was doing the data cabling only) around fifteen years ago which had two electric showers. The system was TNS and the head really old with ceramic fuse carriers. The supply was strangely two-phase and neutral (with only one phase in use) and the electrician suggested getting the DNO to supply a second head for the second phase, with a separate CU connected to it for the second shower. What I didn’t get is that assuming the service head fuses are to protect the supply cable, surely the neutral would be carrying the combined current of both phases? The DNO guys seemed perfectly happy with the arrangement when they came (I recall the guy touching the neutral in the head with his finger and quipping “polarity test”!). Interested to know any thoughts…
The different phases are out of phase so when one is peaking the other is 120 degrees out of phase. They never put peak power out at the same time so the neutral isn't dealing with two synchronised phases which is the problem you seem to be imagining.
@@projectbuild9784 It's even better than that. If you add together the neutral currents from two different phases each being say 10A then the amplitude of the combined current is also 10A (and not 20A). This assumes sinusoidal currents which heavy loads will be.
Hi there , quality videos, thank you.
Do you like the TIS MFT Pro ? Noticed you had a Metrel in another video.
What’s you preference and why ?
Thanks Roger, I have a Metrel MI3100s, a Megger MFT1552, a Fluke 1651B and the TIS MFT Pro just because I like my toys! They're all fine instruments, and I can work with any of them. The Fluke was retired as it lacks an auto RCD test and I was getting some odd readings occasionally on the resistance function. The Megger was my original tester and still works, but I now keep it in a secondary box that is used only when additional personnel are working with us. The MFT Pro fits in my main tool box so is my everyday machine for basic faultfinding, and the Metrel is my calibrated machine used for the EICR and initial verification work. I prefer the Metrel over all the other testers simply because it displays more information at-a-glance. The voltage between line, neutral and earth is always on the screen regardless of the selected test, the Max Zs value for the selected protective device is shown on the display when loop testing so you can see how close you are to the limit, it supports phase rotation unlike my Megger and Fluke models and it works well with the neck strap (I can't figure how the TIS is supposed to be worn!) It also has a good clear display with nice big numbers and can be placed on charge without having to extract the batteries unlike all the others. The TIS machine has a couple of functions the Metrel lacks - PQA and earth leakage, but you need an expensive accessory to make use of them. I have one here, and will do a video showing it in action soon. The TIS has updateable firmware, so there may be an update in the future which allows it to do a couple of the things the Metrel currently does, e.g. show the max Zs for the selected device (it knows the number as it issues a pass/fail when testing, so there's no reason why it shouldn't display it for the operators reference), and show either the voltage or a warning of a voltage when one is present and the menu screen is selected (at present, it's the only tester that doesn't display any indication of live connection when first switched on, you have to enter one of the menus first). The TIS is the only tester of my bunch which can store results for later download - a feature I don't use!
David Savery Electrical Services o
David
Thanks for reply , just brought a TIS voltage indicator after just viewing the video.
Like you I have a megger/fluke and a metrel
Like the touch screen.
Think I might buy the Pro as it’s been a good month.
Love the humour and knowledge base.
@@rogerbean393 Blimey Roger, now I'm getting worried that I'm influencing you to spend too much on the toys!
Your videos are scarey A F. I don't want to touch any electrical switch or socket in my house anymore - fantastic content, how can you only have 6.3K subs?
It's a combination of bad language and uncontrollable nasal hair that keeps the subscribers away!
Really interesting. Thanks, I didn't know you could cook 63amp RCDs without them operating. I don't think I knew that anyway. It's never been an issue. Also didn't know you could get a device to stop two loads being used at once. And good points about more than one lighting cct hanging off an MCB. I always forget to check that before I price things up, and it did once completely snooker me, although I got the money back in other ways as they booked me for the rewire and board change. But it weren't funny. I hate lighting circuits, especially with dimmers and intermediate switches etc, you're supposed to test every damn bit of them, and it just takes for ever.
Hi David a friend of mine once went to a house with 4 electric showers. So he called napit and spoke to an adviser and he said he ust to work Blackpool area and ust to see that situation often and his answer was there is no way all 4 showers could run at the same time any way because the water pressure would not be strong enough.
And it kind of makes sense I know if I run my shower and some one turns tap on there water just trickles out of the shower.
What's your take on it.
I have never actually tested to see if the shower still pulls the 32 amp if water not coming through at full pressure
I can remember about 10 years back when staying at a Park Resort chalet, the electric shower and cooker having some kind of 2 way control switch, meaning when one was being used, the other couldn't. I guess it was their way of preventing potential overload.
Thank you, David, for your upload
Cheers John, thanks for your comments.
Around 4.8 KWh a day leaking to Earth. I worst I found was over 32A leaking to Earth in old stables at a riding school in Kent (100mA RCD fried)!
on alot of livery yards and riding schools as well the electrics are awful so that doesn't surprise me at all
Great vid. It explains a lot. Thanks and subscribed.
I did a test on a split load just yesterday and found all power rhs and all lights on lhs.. come on sparkys really....if you don’t know what your doing just leave it
Great vid once again is there an easy way IE app or website to find out who the snow is for a property
One DNO lookup is here: www.energynetworks.org/info/faqs/who-is-my-network-operator.html
Isn't it possible to have the showers off a separate incomer tail supply fitted by the electricity supplier??
Hi David,
Would it be worth asking for a 3 phase supply and reworking from there?
Regards
yes u right i did not say any thing about the max demand and diversity how to solve the demand .the rcd do not solve the high demand.
Just watched this again 4 years since I first watched it. I will never tire of listening to your geriatric mumblings.
Great video. Really well explained 👍
Interesting that you can get high power single phase line in the UK. In Lithuania, if you want more than 5-10kW, you will get three phases.
You find few overhead cables here unless you go out into the countryside, it's all underground in the urban and suburban areas. I guess when they were rebuilding after WW2, they figured up to 100A single phase ought to be enough for anybody (domestically), although in these days of instantaneous hot water heating, induction hobs and electric vehicles it's all looking a bit creaky. A lot of digging up can be required to upgrade to a three-phase supply.
Great video, just wondered which form filling software you’re using? Thanks
Thanks. I'm using Easycert. I've been meaning to do some videos on using it for a while now, I'll try to get them out this month!
Yes that would be helpful if you get a chance as there’s not much on TH-cam about it. I’ve had to stop using ELECSA online software, it’s just so bad now. Temporarily moved on to Electraform to keep my sanity!
Yeah, the CPS in-house solutions are poor. Electraform looks good, but they're pay by cert, and when I did the maths for the number of certs I issue in a year, I found sticking with Easycert was cheaper. It has some flaws, as I'm sure they all do, but I'll be starting work on those videos soon (it may be a three-part job), so watch this space!
Hey, thanks for this video. How does current leakage occur? How is it getting on that earth wire?
I'm not showing the current leakage measured properly here as others have commented, but where it is coming from this installation, it'll be either through appliances that have a natural leakage such as with some electronic equipment, or more likely through poor insulation resistance. Two of the socket circuits on this RCD have zero readings when I.R. testing, and if the RCD were operable then it would be tripping all over the place.
good video mate informative and to the point well done
will you have to remove some of the loading so it sits under the 100hrc main fuse ? be nice as i'm a crap 16th ed spark. great video's as i'm learning more now than when i was at tech.
Hi Dean. I'm always nice! Well, mostly. But yes, two of the electric showers will be booted out. One's going on the boiler, the other is being converted into a utility room.
@@dsesuk many thanks and keep up with the great vids
Do you get fries with an EIC?
Great video, be great if you could do a follow up
just been testing a few properties with the issue regarding maximum demand, what did you code it as ive not been able to find any info from bpg4 ot any forums, last resort will be to call niceic
If I think too much current is being pulled through a device not rated for it, then I'd code it C1 Max. This isn't a fault current issue, it's the everyday design current that hasn't been factored in here.
100 amp single phase? It amazes me that three phase isn't used more often with so many large loads. One shower per phase, split the other loads as well. Reduce voltage drop.
Here (South Africa) I have 3 x 60A incoming (now it's normally 3 x 80A).
It will amaze you even more that the dno's give each property a diversity of only 2kw when designing their network. So on a typical housing estate with about 150 homes all capaple of drawing 60 to 100 amp each!! Is all fed from only a 500kva or 1mva transformer which is only capable of delivering around 700 to 1.45ka! If that is not diversity i don't know what is, and amazingly it all works!
Am I correct in my understanding that the leakage current can also come from switched on electronic devices as well as the low insulation resistance on the cables themselves?
Electronics can add to the leakage current which is why the likes of server rooms and I.T. suites need some design consideration (not that I've ever installed such).
Really useful. When are home buyers going to start asking for these reports before purchase.
I know. You wouldn't pay top price for a car without an MOT, yet people just aren't aware of the checks they should be doing before forking out five or six figure sums for a house.
In South Africa it is a legal requirement to have the full electrics tested, you also have to have the water and woodwork (roofs, floor joists). Means that cowboys cannot get away with things.
I thought it was required as part of the house buyers pack
@@curtisj2165 I believe this sort of thing was required as part of the Home Information Pack in England and Wales, but then the HIPs were scrapped a few years ago. We still come across plenty of people who ask us to perform an EICR after they've splashed out and moved in.
David Savery Electrical Services o
I like all the information. Wouldnt it be better to use two or even three split boards? One for running the other two and common areas? then one for the sections? Shouldnt the Granny flat have its board in the flat, like a Shed? So in effect, board one from the meter would be three outputs for other boards, plus common lights, second board for main house, third board for granny flat, ad fourth board being shed?
In USA and Jamaica the granny flat and the shed are usually on their own boards, as sub panels from the main board. In Jamaica actually a multifloor house is usually set with a panel on each floor, for that floor, and a main panel supplies those panels.
Hi Adam. Had this been my design when being extended/renovated, then I would have made a more logical layout of the circuits and perhaps used a sub-board to split things off. Sadly, what we found here was a builder's breakfast that someone had thrown in about fifteen years prior. A lack of planning and execution left the place with more circuits than were needed all coming back to an oversubscribed board in a single location. When we performed the remedials and upgraded the board in a later video, some of the circuits were combined into more logical arrangements, but without being able to damage finishes and renew large parts of the wiring, we were left with the single location and making the best of what we could.
David, that was an interesting video, sometimes it’s unbelievable what you actually find. I find it hard to believe that there’s 3 electric showers & 2 cooking circuits as well as everything else. In a domestic situation, sometimes, I just don’t want the rectifications. It would be interesting to see the EICR & your reasons behind the coding. It would also be interesting to see your plain English version to the client. I have found electricians tend to code & have different interpretations of the regs. I have installed a priority switch many years ago for 2 showers. I am curious to know what you would do with the third.
Thanks Patrick, you're right about the coding, it is open to interpretation and often down to the discretion of the inspector as to how something should be listed. Besides that, the report is an awful form and there's nothing in the inspection schedule checklist specifically about demand. Apart from the individual circuit faults, the failed RCD I've coded as a C2 in item 4.8 (manual operation of circuit breakers and RCD's) because it won't react in the event of a leakage fault, and as a C1 in item 4.19 (RCD's provided for additional protection) as it's handling more current than it was designed for, so all bets are off as to how it will react. The failed RCD also shows up elsewhere on the checklist of course (items 5.12.1, 5.12.3, 5.12.5 and 6.1). As the demand of the installation is potentially more than the service head should be handling, I've put that as a C3 in item 1.2. It could perhaps be argued that a C1 or C2 applies, but it's been coping for the past fifteen years, and besides the common sight of the tarry insulation having leaked out, there's no outward evidence of it being unable to cope. Other's may have coded things differently, but whichever way you look at it, the report deems the installation to be unsatisfactory with 23 observations listed, and the covering email that went with it had about 1200 words explaining the issues and what needs to be done. The client tells me she has already contacted Western Power about putting in a new 100A PME service and isolator after I sent her a link to their contact form, and she has asked me to go ahead with a board change plus remedials so we should have a follow-up video in a few weeks.
@@dsesuk congratulations on being awarded the remedial works.... I think🤔🤣
@@mickbitchum4664 It might be a bit of a short straw job!
Even with the service cable changed and new 100amp bs 88 .the circiuts demand current is still over 100 amp supply ..
3 showers 40 amp each ..NO DIVERSITY ON SHOWERS SO 3X 40 120 A ? .
A 3 PHASE SUPPLY IS REQUIRED ..
Yes the RCD main switch is fried but has the DNO service fuse ever blown... It looks as though the service cable has suffered the most as a result of the overloading.
No degradation is apparent on the service cable.This is just standard PILC with a cloth outer covering.
Given the state of that system, it's almost like there isn't a working fuse in there.
When negotiating a reduction on the purchase price, would you expect vendor to pay for C1 and C2 remedial work?
Hi Neil. When we undertake EICR's, we try to provide a fair reflection on the state of things which can be tough if appointed by either the buyer or seller. The former can of course use it as a stick to beat down the price a little if things are bad, but if someone hasn't invested in maintaining their electrical installation over the years, then they shouldn't be too shocked if it bites them on the arse. It all depends on what the buyers plans are. C1/C2 issues probably aren't really issues if they plan a back-to-bricks refurbishment, but if they pretty much expect to move in and start living with things as-is, then they may want to negotiate on price if the seller has let things degrade or had a pop at poorly making modifications.
Your description of the property - two pre-war houses turned into a mansion - if the price goes into the millions I call them that.
I've got a copy of BS7671 and I've checked through the model forms but I can't find the place where the demand would need to be recorded or even where it is requested. Are you able to point it out?
On the EIC it's on page 415 of the blue book under Particulars of Installation Referred to in the Certificate. I don't think it's ever been on the model EICR, at least it wasn't in the preceding yellow or green books. The software I use to create certificates and reports, Easycert, differs from the model forms as most third party certs do, and it is something listed on an Easycert EICR. I don't know why it's not a part of the model EICR as it seems it ought to be.
I enjoyed it. Why are you wearing a cap under the stairs? are you allowed to be there?
Keep the cobwebs out of my hair!
David , Can you tell us more about your MFT you are using ?
That's the TIS MFT Pro which I carry in my main toolbox. There's an older video of it where I was a bit sniffy about the thing after I bought it in 2018, but I get on rather well with it after a firmware update addressed the main issue I had at the time. I keep meaning to do a new video showing its cheaper sister, the MFT Eco, and how they compare, but there are never enough hours in the week.
Hi i am wondering why in the UK households always use obe phase system while here in Croatia most of the houses use three phase(my little 75 sq m apatment too).That house you are working in seems huge and they only have single phase electric. Why? Isn't three phases much better. For instance cooker in Croatia is connected by three phase and it has same power as one in the UK, while using much less power per phase. Wouldn't bringing three phase into that house solve all the problems?
I don't know, but I assume it's down to cost. I don't know what it's like in Croatia, but unlike many countries our cabling infrastructure is largely all underground in the towns and cities, and I imagine that after World War II, those responsible for rebuilding figured 60-100A single phase ought to be enough for anyone domestically. Generally, it is, but where a service needs upgrading, a lot of digging is called for which is expensive on the public carriageway, and not very desirable for someone who has a smart looking driveway or garden in front of their house!
Considering the amount of defects would you not of recommended a rewire? Good vid, very interesting
It's not necessarily worth throwing out the baby with the bathwater. Most final circuits tested okay. Some rooms are being refurbished, but others are in good nick, so hard to convince the homeowner to start knocking holes in the place unless it's really a write-off.
A question please Dave (or other qualified electrician)... should the sum total MCB amp rating never exceed the main service fuse or does diversity apply...e.g. is 60 amp service with 80 amp total MCBs allowed ??
It seems like a situation of overload would exist in this case if , theoretically, every MCB was at max load ??
Adding up the sum total of MCB ratings would blow maximum demand in most properties, so diversity is taken into account. Some circuits, such as those electric showers, are going to be taking near the rated value, but that's usually not the case with lighting and sockets. It can be tricky to work out, you could have two small houses, one with two socket circuits, one with a single socket circuit, but even if they had the same appliances and the same number of outlets, the one with two circuits would, on paper, have a higher maximum demand if calculated according to the regs.
Yes your right diversity should be applied, as you said if all mcbs were at full load they would exceed the rating of the main fuse in 99% of modern installations, most homes have a 32A circuit for cooker and a couple of 32A socket circuits, chuck in a 16A water heater and 2 x 6A lighting circuits and your way over the normal 100A single phase supply. Also many new homes are increasingly being fitted with 80A supplies so diversity is definitely needed. There are tables in the on-site guide for guidance on diversity but they are really outdated, especially with the influx of LED lamps and energy efficient appliances. Personally I think It's best to look around the property and check what lamps/appliances etc are in the home and calculate the demand that way
If I remember right John Ward did a good video a few years ago about maximum demand and Diversity which is worth a watch if your interested 👍
@@mickbitchum4664 th-cam.com/video/Wq0uODypaGI/w-d-xo.html
@@tbohlsenNSWSSMRC Thanks for that, I've seen a few of the great man's vids, but I don't think I've caught that one, so will tune in!
Interesting how popular electric showers are in the UK. Do they actually save money over an off peak storage tank or is it purely done for convenience and space? In Australia we generally have instantaneous gas or gas or electric or even solar storage tanks. Of course we don’t have a ring system either so you’re probably wondering how we survive without getting electrocuted daily :)
It's a convenience thing I guess. Traditionally, people did have hot water tanks, but they're generally ripped out of our pokey little homes for more storage space. Electric showers are easy to install and can heat water on demand which makes them handy for a larger family environment. On a back-to-bricks refurb, a combi boiler which can heat the water via gas would be better. Don't knock your lack of rings, they're awful things, a throwback to WW2 that nobody else in the world bothers with. I don't install rings myself, they're for the old boys who won't change, or the cowboys who know no better!
David Savery Electrical Services Oh I know rings are a pain compared to a conventional radial circuit. Did they come about because of a shortage of copper in WW2?
@@mondotv4216 So Wikipedia tells me!
Is there a calculation that could be applied to work out the maximum demand?
See Appendix A of the OSG for maximum demand and diversity. It's a tricky one as you can never really be sure what the client will be connecting up, but unless you have known load values, then you assume 100W per lighting point (and can then take 66% of all lighting overall), 100% for the highest rated two electric showers/instantaneous water heaters, then 25% for any subsequent, 100% for the highest rated socket circuit, then 40% for each additional, 100% of any immersion heaters, cookers are 10A plus 30% of the remaining load plus an extra 5A if the control unit has a socket built in (etc.) I've also done it via measurement by using a clamp meter set to record a MAX value over a period of 24 hours average use. Usually you don't have to worry too much about it, unless you come across an installation with some heavy circuits such as multiple showers, car charge points etc. or if you get called out somewhere where the main fuse has blown without an obvious cause.
@@dsesuk sounds like a lot that I need to get my head around then. Will research more into it. Thanks for taking the time to reply. Great vids btw 👍🏻
I thought you had to contact the dno if wanting to connect two or more electric showers?
In theory, I think (and I may be wrong) that if your MD exceeds 60A then you're supposed to inform the DNO, but in practice I've never seen it done. The only time I inform the DNO of a load to be connected is on a car charger installation. Personally, I wouldn't recommend more than one electric shower on a 100A single phase installation, and if more than one is insisted on, then I'd advise a load sharing option such as the Garo product I spoke of in another video. I suspect that most installers just do what the client asks for, and to hell with the consequences because nobody is policing anything.
Those lenovo laptops etc kick ass, do you have an ssd in it?
No, still on a hard drive, but I have upgraded it from a 6-cell to a 9-cell battery, and I got hold of the 3G internal modem so I have data access on the move. I might do a video on it in its own right one day as it's a great bit of kit!
@@dsesuk the only machines i buy, you can get fully working 2nd hand desktops for 27 quid lol, no monitor ofc, but they can make your tv cleverer :) the improvement with an ssd can be phenomenal, boot times and program start up times decreased significantly, trying to learn some electrickery so i am watching your great videos, thank you
Great video thanks for the upload. I was looking at purchasing the TIS earth leakage tester, any good?
The TIS MFT Pro is a pretty capable multifunction tester, but for the earth leakage function you need the clamp accessory shown here which is sold separately and is pretty pricey. Mine has been loaned to me by TIS so I can show it on this channel. This was my first time using it, and the test shown was rather simplistic, I'll have a better video about it in the near future. The little clamp meter I have is a low cost solution for measuring leakage current.
@@dsesuk thank you for the update. Keep up the good work.
When coming across properties where it looks like maximum demand will exceed the main breaker rating regularly, do you make a recommendation on the EICR for a three phase consumer unit to be installed ?
Hi Ryan. Getting three-phase into a property is no easy feat, nor is it cheap. Here it would involve digging up the driveway, and to be honest 100A single phase is enough if it's loaded correctly. I'd be more likely to look at reducing load such as by changing halogen lights to LED or decommissioning a shower, or shedding it by using a device like the Garo priority unit I blabbed on about in another video which, in my case, allows my car charger to share a circuit with an electric shower by ensuring only one can be in use at any one time.
David Savery Electrical Services I appreciate that, and a priority unit is probably the best option for economic reasons. If somebody is buying a £1 million house, I imagine money would not be as much an issue for them, and if they wanted to use several showers at the same time, and ovens etc, then I guess you would suggest it to them ?
David Savery Electrical Services Would there be any circumstances where you would suggest three phase ? Do you know the costs of the DNO to run a three phase supply into a property, it’s an area that interests me.
@@djryanking I don't know the costs I'm afraid. I know it's the best part of £1k just to relocate a service head, so I suspect beefing up a supply cable from the street into the property would command a pretty strong price tag.
The tails going to the cutout look like 16mm. I bet the cutout is 60A, which explains the overheating. Those things can carry 80A for quite a while. The board is a real mess!
Not pretty is it?! It is 25mm on the tails there. We had Western Power out yesterday who have confirmed it's a 100A fuse, the earthing is properly soldered onto the sheath and the cutout is in good nick. They've rubber-stamped it as fit for purpose to carry on, so that's some good news for the homeowner!
Would it not have been more accurate to measure the earth leakage by putting the clamp around the line and neutral and measuring the resulting difference between the two? By measuring the earthing conductor you only get part of the earth leakage current as the rest will be flowing through parallel earth paths like bonding, pipework etc.
Yes. I'll show that in a future video.
Very interesting Thanks Dave
When you filled out the condition report what figure did you put for maximum demand?
An excellent question, and one I cannot answer tonight as I haven't compiled the full report yet. I have the raw data for all circuits, so I'll go through it this weekend as I prepare the paperwork for submission to the client along with the invoice. I'll let you know when I've worked it out!
Hi Curtis. Have just done the calcs as I prepare the report. The figure on paper is 236 Amps. It isn't really that high, but because there are five 32A ring circuits it gets bobbed up artificially if calculated according to Appendix A of the OSG. I've taken diversity into account here, 66% on lighting, 10A full load plus 30% of remainder for each of the two cookers, 100% for two showers, then 25% for the third shower. 13A has been allowed for the shed where there is a single socket outlet and 13A for the water heater. Max demand calcs are a bit of a nonsense though as splitting up socket circuits just drives the numbers up on paper even if the number and utilisation of sockets remains the same. Usually, I just add up the MCB's and multiply by 0.4 to get an (arguably) more realistic figure. I know other sparks also do this, but I'm not sure where it comes from. Doing it using the 0.4 rule-of-thumb would give a figure of 168A in this case.
I find the formula a bit of a nonsense personal. Nothing like experience when calculating maximum demand.
Are you sure that the brown has been used as the neutral at the RCBO? I think you've made a mistake. Remember that different RCBOs have their connections the other way round. The brown is at the front and going to the upper L terminal. The upper terminal is always the front and lower always the back irrespective of which one is L or N. The only swap is the grey and black.
Hi Kevin. That was a 'voice typo' addressed in the description; I said brown, but I meant black. I didn't notice the error until after upload which is why there is no on-screen correction.
What is the story behind the McDonalds cap? I got more interested in the hat than the faults. Lol
Daughter #1 used to work there, so it's spare and...well... I needed a hat.
Fair play to you. 😂
Good point.. Well raised 😉👍
Superb video!!
Great video!
I need to follow your example of filming on site more!
What is the difference between EICR and NICEIC? I had a certificate for the latter when I bought my home but I've found nothing but horror shows all round the house. You wouldn't believe some of the things I've uncovered.
An EICR is an Electrical Installation Condition Report which is a process that may be undertaken by a suitably qualified and insured electrician to ascertain the current state and safety of your existing electrical installation and to compile a report compliant with that laid out by BS7671 showing the results of the test and inspection process. NICEIC are an accrediting body the same as NAPIT, Elecsa, Stroma, NAPIT et. al. Someone registered with an accrediting body should, in theory, know their onions, as continual assessment by that body should ensure they're working within their means. My company is accredited with NICEIC to undertake EICR work as I hold specific qualifications and professional indemnity insurance to do so. Someone else may be registered with another accrediting body to the same standard. That said, you'd be amazed at the crap reports we come across, both by chancers who aren't accredited at all, or by those who are for installation work only but not testing/inspection. If you think you've been short changed on an inspection by someone who is accredited, it may be worth speaking with the accreditation people on their helpline number or to have someone else cast a second opinion.
@@dsesuk Thanks. It was a number of years ago and I've put right most things myself as I went along, while my builder Dad did extensive work on the home, replacing walls, ceilings, floors etc. I saw things electrical wire running over heating pipes, an outlet spurred off the cooker socket and installed on the inside of a cooker extractor (where the steam from cooking passes directly over it) to power the fan, metal light switch face plates which aren't earthed, wires running out through the wall on the outside of the house, going in through the top of the junction box with a busted gland and cloth tape wrapped round it.... just off the top of my head. These all felt like one off things at the time I put right but they all added up to make me wonder what other sins are going on that I haven't seen. I did notice the old black and red wiring in the ceiling in parts of the house.
Excellent video.
Love it. Good show
Good vlog was talking about max demand earlier today
Not while down the pub I hope...??
Never talk about work I. The pub🍺🍺
In the Shire of Will the Bard, I would have expected some Quipping and Japping
As soon as you see an SwA terminated without a gland the alarm for shoddy work and incompetence should ring loud.
3 showers on the go in the middle of winter must be pushing 100 amp?
Easily as David mentioned, Each shower is almost 9KW.
27000:240 is yr answer. Bye bye main fuse.
This EICR has possibly saved the property owner from a house fire!
Another good vid thanks
by looking at that
likely ex gov 50's-60's house with retro fitted rcd that is only really designed internally in the rcd itself to hold 1 circuit unlike the 10-20 amp breakers of yester year where you overload to a degree before frying the break..
with the the rcd breakers are built today it is 1 point to 1 circuit
I suspect with the granny flat modification you are looking at the power co to come and install a 200-300 amp service
split between each home area..
looking at the extension i would say dyi bodge job within the life of the home
my opinion i'd do an electrical gut and bring it into todays code rather leave it alone and do a date of install grandfathered mess
the main rcd should be around 100-150 amps
covering 2 30 amp circuits 2-6 15 amp circuits wall circuits, 2-3 10 amp circuits for lights..
@Cupid Stunt in australia skinny 80 amp main breaker with 2 x30 amp breakers feeding 3 single points and 4 double points and the other feeding 3-4 double points
on 15 amp domestic wiring .
1 circuit has 2x outside singles, 1 internal single (fridge), 2 points double (bedroom)
2 points bathroom 1x double washer/dryer 20 amps draw, fridge 10-15 amps draw..
on an 15amp domestic wire.. @240watts mains
though the basic point that the point to save cash 2xc15s were used where they could of wired each point individually given the amount of real estate in the fuse box..
Main point I was getting at most likely would been better if this was an ex council rental would of been to gut completely than mess around with the bullshit of grandfathered date of install which leaves people that don't know any better of blinders on see no evil, report no evil..
I am a firm believer of meet or exceed minimum electrical safety codes of today than live in the grandfathered systems of date of install.. as it leaves the consumer in a legal time mess
Maximum demand can be alleviated slightly with led lighting, new energy consumption appliances and going to gas hot water. Correct , split the sub circuit rcd to rcbo's. It is not to wiring rules to have multiple circuits on an individual rcd now.
LED lighting is a no-brainer, gas appliances are fine, so long as you accept that gas is on the wane and will cost a lot more a few years from now (there will be many switching from gas to electricity in the future). The wiring regs do still permit the use of RCD's for multiple circuits however, in fact, 18th Edition introduced a new reg specifically stating this, 531.3.5.2, although the implementation on this site is poor.
@@dsesuk My work is in Australia and rcd circuit protection cannot be greater than a 50/50 ratio. In other words if you have 4 power circuits then they have to be on a 2 to 2 rcd ratio and not 1 rcd for all. I have found recently with the more reasonable price of rcbo's that the majority of customers will go with all individual circuit protection on light and power circuits. We normally install a 3 phase service line and there is no problem with max. demand issues. It seems the installation there has not been inspected by the regulatory authority. Probably a cash job.
@@ottoschless4115 Ah, well you probably have more sensible rules than us - the regs here didn't even acknowledge the RCD issue until last year's 18th Edition, and even then it seems to rubber-stamp it rather than recommending a ratio. We're mainly single phase domestically here, and with most services underground that isn't going to change easily. As for regulatory authorities, there are none. This was probably all done by the builder rather than an electrician, no certificates, no warranties, nobody checking until it's all too late!
@@dsesuk Thanks for your reply. The electrical trade there really needs some scrutiny, otherwise you will be inundated with cowboys. Hopefully nobody gets injured or killed by someones stupidity. If you are correct and the builder did it, ( electrically unlicensed ),well he will be severly fined and punished here. A notification of electrical work certificate must be given to the regulatory authoriry here when the connected load is increased with any additional installation. Anyway enjoy your work.
What’s the technical name for the shower sharing device? Thanks in advance
It's a series of interlocking contactors (typically with current-sensing relays). The purpose-made assemblies are typically referred to as "priority units".
@@richardwalsh5882 Garo are the only people who make the priority units that I know of (at least, they're the only ones I've installed), and I've had to order them in from Meteor Electrical in Ireland. I don't know why they're not readily available over here as I imagine there are a fair few sites that could use them, especially people in my position who want to hook up an EV charger to an already heavily loaded site.
@@dsesuk
Cheers I've never even heard of these. Fortunately I can't remember ever installing more than one electric shower in one property. Maybe installed a mixture of combi and electric. 👍👍 Good video
I wonder if they meant to fit a 63A rcd and breaker combo (or that was fitted till they got fed up with the "nuisance" tripping and got a fuckwit who just replaced it with an rcd)
Apparently some people confuse the rating on the RCD thinking it will trip like a breaker at its rated current, not realising that RCDs don't work like that. I've seen a few videos where plain RCDs were installed as if they were MCBs/RCBOs, with the installer apparently not knowing the difference.
Bring another phase in. It might sound clever to put a contacter in so only one shower can be used at a time, (which is all that is actually needed to do the job, nothing new or exciting about that) but if you do that, what exactly is the point of having more than one shower? You'll end up with the usual scenario of teenagers fighting over the shower at weekends. Which is probably why the extra showers were put in to start with.
If your adding circuits to an existing install and not even labeling the circuits....then you should ensure your spurs dont mark the floor whilst you are there
Got the EICR codebreaker well worth the beer money.ah!!!
Good job
Good. Video as always hope you got the job?
Not sure I want it! The board change isn't too bad if you don't mind the cramped conditions, but finding the IR faults is always a nightmare.
Great vid rick 👍
I think autocorrect has altered your spelling of 'prick'!
David Savery Electrical Services 😂😂 no no but you do resemble him with you humour great work keep it up 👍