Am I WRONG for doing this?!
ฝัง
- เผยแพร่เมื่อ 22 พ.ย. 2024
- let me know your thoughts on the PME or TT debate with reg number below for every one to learn from as this is such a split argument online
Check out this Idea List on Amazon: Useful tools for a spark by N Bundy Electrical amzn.eu/1e1wXnr
Use code BUNDY25 at unilite.co.uk/... for 25% off
Use code BUNDY10 at www.expertelec... for 10% discount
Join this channel to get access to perks:
/ @nbundyelectrical
This video is for entertainment purposes only and is in no way intended as a guide or 'how to'.
Personally, I would TT the whole of the sub-board, feed L+N to it from the main via a double pole MCB to protect the cable, then local earth rod, local MET and sub-board in TT. Then the garage, hot tub and car charger would all be TT. Place a sticker on the sub-board stating its TT and the Ze reading. In otherwords treat the garage a bit like an out-building that needs TT. If in doubt ask John Ward for an opinion.
Apologies, I commented before reading this... BTW, this is now in the regs (Am 2)!
I still fit a spike in most cases. I do my own risk assessment- if the user can have one foot in the tub and one on grass or another earth path while entering/exiting I’ll TT it. If it’s mounted on a slab or patio and this cannot occur I’ll happily PME it. Just be mindful of any potential touch voltages when going TT. I think this is belt and braces but I’d rather be over the top than stood in court.
The slab/patio is the same earth as the grass. Both could be wet and thus get a relatively good connection to your foot. You are treating them differently because resistance through grass/dirt is lower than through concrete/stone?
Mentioned this on your instagram post also. I personally would risk losing a PEN over a failed rod and failed RCD. Installing a rod doesn't cure all your problems, it just moves the goalposts. So for that reason I would use the PME earth for the hot tub over the rod.
A separate Earth Electrode TT Earthing is required for all outdoor hot tub installations for houses on a PME Earthing arrangement (95% of dwellings) This is usually connecting the SWA tail earth within the isolation switch to an earth electrode and NOT Linking it to the house PME earthing arrangement (MUST BE CARRIED OUT IN ACCORDANCE WITH BS7671 SPECIAL LOCATION 702). I got this from a hot tub supplier/installer ( "HOT TUBS OXFORDSHIRE"). They even suggested phoning them if you have electrical connection problems! Hope this helps--good luck
Always enjoy your vids trying out new tools, new ideas and new solutions. I fitted a hot tub supply last year and put in PEN fault detection. I would definitely do the same again, belt and braces and all that.
I would have been inclined to have TTd the garage DB. With there being a car charger and a hot tub it solves the issue of should it/shouldn't it. Great vid again. 👌
With the hot tub and car charger i would of fitted a new consumerunit with a pen fault device .
Electrical stuff aside….as a fellow father, I appreciate the bracelet so much!! I have an arm full of similar items! Great one as usual
Glad you've addressed this, as a townie, I've rarely come across TT, and certainly never installed hot tub supplies. Once you've digested the responses, could you do a follow up vid?
We do quite a few, most of the new build estates where we work are PME, (they're the ones who can afford hot tubs lol). We almost always TT them. I personally do NOT trust TN-C-S at all
@@TheChipmunk2008 Cheers for replying. Why don't you trust TN-C-S? I understand PEN faults are fairly common, but otherwise it seems a decent earthing arrangement?
At the end of the day it’s down to the manufactures to tell you what earthing arrangement to use on there hot tub. You still do a personal risk assessment but they should provide you the information as it’s there product your installing.
@@Baggiolyful the problem is when you get a hot tub that comes from another jurisdiction like the American import ones that specifies things that don't even exist in bs7671
@@mrclive5 if my so-called earth connection is able to go to 240 v at the drop of a single connection I don't consider that to be appropriate. Tncs is basically a complete cop-out that shouldn't exist
Got a handy tip for you Nick / Adam, keep an oily rag in your tool bag it should help stop your tools from rusting
Keep the silica packs that come with gear that you order, in your tool bags to keep the moisture out.
I just chuck hand full of those little packets you get in trainers etc in bottom of my bag never had an issue with rust.
A lot of newer hot tubs have metal frame work,pumps & heaters it’s all bonded to the main earth bar in the hot tub.
I’ve always been told to rod hot tubs & pools, especially on PME, the reason is when the local network is at the maximum load on one phase there can be a 10v difference between the PME earth & the true local ground.
It would be possible for people with bare feet to feel this
They would feel a 10V delta for PME and TT? Really?
@@ColinDH12345 I’ve heard of people feeling it
When I had my hot tub done. It was PME from house to garage, then to rotary isolator. I think the PME and the TT earth went into the isolator. The PME earth was wired to the armour of the cable supplying the hot tub, but a plastic gland was used so the 2 earths were not connected together.
I Normally use that Ho7 flex for connecting cookers and hobs. I wouldent call it hi-tuff as it’s finely stranded conductors where as hi-tuff only comes in solid core conductors
It would be useful if the mat e type devices were in the regs for this type of installation (intended departure maybe?). My main concern would be that the rod could be too close to another earth (pme) so you may not have made a tt. If cost wasn't a concern an earthing mat with the slab would be best.
Napit have a suggested label marking.
For PME to TT earth system.
" Warning this junction box contains PME earthing on the supply cable which has been intentionally seperated from the TT earthing system of the outbuilding "
I think its wise to mark and cover yourself 👍
Napit is private thing nothing to do with basics of electrical knowledge , laws and physic. For money they can say that white is black!
@@adriantopor9015
I think basically the theme here was labelling and not electrical knowledge 👍
This video sent me down a rabbit hole of John Ward videos! Basically, are the bonded water and gas pipes electrically separated from the metal pipes in the ground? Is the earth electrode 10 meters away from anything in the ground that's bonded to the TN system? If not then the earth electrode might still be somewhat electrically bonded to the TN system via the ground and is therefore not a true TT system. But it might be a good idea to connect the PME in with the electrode as the electrode will give you *some* protection the the event of a PEN failure. I do wonder, if it's protected via RCD, would the electrode only have to allow enough current to flow to trip that? I'm far from an expert at this though, I highly recommend John Wards video on the subject. Search adding TT or ground rod to a TNCS installation.
Hot Tub could still be class 1 even if it appears to be all plastic. as the heating element internally (in contact with the water) will have the cpc connected to its metal covering?
I'm far more concerned about 240v outside garden lighting, so many more ways for that to kill someone than a hot tub - yet we keep installing them
12V dc every time for my garden lighting. No RCD issues or melted dogs.
Lower voltage increased current on secondary both can be deadly. Each application to use 230v or ELV
I'd have personally used a 2 core SWA and a plastic gland and some heat shrink on the armour at the other end to save me the hassle of having to mark it up.
Yeah.... bit this gives you the option for the enevitable short lived regulation change at some stage in the future. Or a change of use...
I like you're style .Nobody knows everything and you come across very honest.
How long do you think it will be before the regs start requiring whole-house PEN-fault detection? Maybe a larger meter cabinet with PEN-fault detection and SPDs before the meter tails even enter the house.
Maybe the Matt:e ARD-1-100-TP for three phase supplies - Sadly they don't make a 100A version of the single phase unit but I'm sure they could produce one for you if needed.
Professional Electrician and Installer magazine Summer 2020 has a good article about hot tubs, certainly worth a read. It goes into why a PME earth isn’t the best solution. As for the two earthing systems in an electrical enclosure I don’t see an issue. It may be worth taking into consideration when installation the garden lighting which earthing system to use, if there’s any exposed conductive parts which are simultaneously accessible from the hot tub it will be a good idea to have them on the TT earth also.
Hopefully the customer won’t smash their door against the rotary isolator too often.
We checked, doesn’t open that wide so all good 👍
Lol. Had a shortsighted day once and I installed a lovely ext double socket / door stop once.
What reading did you get for the TT spike Nick?
I don't see a problem having both earthing systems labeled in the enclosure. You defiantly did the right thing by adding a spike not knowing the specs. I fit alot of supplies for masterspas and American whirlpool branded tubs and they both spec a TT throughout there entire range 👌
H07 and high tuff are two different types of cable high tuff being NYY-J the difference is NYY-J having a bedded inner sheath similar to SWA and also NYY-J normally comes with solid conductors.
I think the confusion comes from the fact before the Normalized cable specs, H07 was known as Tuff Sheathed (or tough rubber sheathed)
Nyy-j and high tuff are not the same high tuff is a Bs registered cable made by Doncaster cables nyy-j is a European cable with no bs standard so not covered by regs. Also high tuff is 90 degree rated nyy-j is only 70 degree rated there are more differences but this comment would be a mile long efix did a video explaining it all
Im not an electrician, but just wondering why a Pen Fault Device couldn’t be used on a hot tub? & does this solve the PME/TT Debate?
Indeed it would, but they're quite pricey :( TT is a cheaper option
Mainly cost !, ive not fitted many myself but if there anything like RCDs (seen many fail) then I would just go TT
@@TheChipmunk2008 thanks for confirming 🙏
Hi Nick, love the videos, personally I TT Hottubs, they may be class 2 but the water heaters within the control panels are class 1 and are earthed. Therefore the hottub water and heater could become live. I personally install the rod under the hottub and install it before the Tub is sat down, seperate the TNCS at the control panel and label accordingly. If the Tub is sat on decking or is inside i may use PME, similar to COP4 with the EV chargers. Also as far as im aware PEN fault devices are not permitted to be used on hottubs, however thats just what ive heard. Cheers mate keep up the videos 👍🏻
I would avoid using an earth rod if at all possible. See John Ward's excellent video on TT problems for the reasons. Re the Tub being a class II. I know nothing about hot tubs, but surely if it is a class II then you will be advised by the manufacturer NOT to connect the CPC to the Tub. No Earth connection - No danger from a broken PEN. Am I missing something?
Surely a TT earthing arrangement provides increased electrical shock protection for an outdoor hot tub?
The regs state All electrical accessories and equipment should be installed according to the manufacturer instructions. So that is my advice . As you say it's a grey area. But you did the right thing by keeping your options open.
Put silika gel bags in the bottom of your tool bags, they will capture the moisture! Get them in most products now days!
Don't eat them though.
Should be ok ,however what if a next door neighbour also has one installed and does connect , who wins at the party wall /fence ?
At the end of John Wards Vlog on TT and TNCS issues he basically suggests there is nothing wrong in connecting both, just in case the neutral on the TNCS system fails.
Actually when I did my own out building I TT'd it. But after a while. I messaged the voltage differential on the earth's. Less that 3 volts. So I connected them together. And were left like that. Did result in a very high fault return value.
@@graham121150 would have though connecting together would have bought down zs reading?
Guys love watching and seeing your fabulous neat work. May I suggest you fit a small earth pit as you have put a surface electrode box that is extremely vulnerable to damage from mower , strimmer and dog damage. The reason I say this is I have had to replace a ripped to bits earth electrode box / cable from dog damage and have also been to a property with no earth reading which I discovered it had been strimmed through over several years of gardening.
He said the grass will be replace by gravel...
@@HenryLoenwind I got that with the proposed new garden layout in the future.
Goodness - I’ve never come across this problem.
A better solution might be just to train the dog!
@@markpunt9638 The dog already knows how to use a strimmer, what more do you want?
Getting nearly as good as Artisan at blowing out bricks LOL.
Although the Hotub is class 2, earthing of the heating element and motor casings will be in contact with the water, which most likely will be full of chemicals which will make it more conductive.
ive seen it , with a close coupled non,conductive enclosure. .underneath. earth ends in it ...L N. continues through to isolater ,etc...bottom enclosure , sealed and labelled, " NO EARTH,S TO BE TAKEN INTO THIS BOX ".
That's a fan over run on the little heat gun is to cool it down before it shuts off
I’m no expert, this is only my opinion, but if the hot tub is double insulated surely earthing through the mains supply is better as you have a direct cable connection back to the source. No matter how good a resistance value for an earth rod it must be higher than the mains earth and therefore not as safe?
What's the point of the RCBO's? If its a new build then surely the supply to the garage would be covered by a 30mA RCD in the house consumer unit?
I'd guess the main CU probably had RCBO's as well
It would only trip the one circuit that is at fault, leaving lights, sockets etc powered on still in the garage.
@@PF-gi9vv if 30mA at main c/u governing sub main to garage, there is no need for rcd protection in sub board. You’re just doubling up.Also unsure what size cpc you used for TT connection. Would of been better to have all of garage c/u on Tt and disconnect earth in sub board and use rod earth instead. Easier to verify reading in the future
You have never lost a lot of food in a garage freezer have you!
@@ColinDH12345 Colin my point is if there is a 30ma trip governing the garage submain and then say a 20amp 30ma rcbo for the sockets in the garage, both trips will operate if the event of a freezer fault so you are going to lose the lot anyway
It is my understanding that there is nothing wrong with having PME and TT (or more accurately, an earth rod) in the same CU, so it should be OK in any box. Besides, it's the same thing that happens when you bond to a water pipe. BS7671 covers this.
But the regs want the earthing to be below 20ohms with pme, that's not really achievable with 1 rod.
@@Aaron-ep1ik In Amendment 2, a Main Earth Electrode(s) to the MET, in Addition to PME, is now a recommendation (as a backup in case of PEN fault)! - expect it to become a requirement in future editions...
You know that electrical soldering torches have a hole for heat shrink or you can remove the end and put the heat shrink shield attachment on the end and have it setup for doing heat shrink
“I promise I will put a link to the things I bought” yep
I have now 😂
As long as the distance between the new earth electrode and any metallic pipes coming from your neighbours is 5 to 10 metres away, should there be current leakage from the neighbours it will be induced in the new earth electrode and that would pose a danger inside the shed. One should consider using a 3 core x 10mm^2 SWA in such a case
Would have liked to have seen the reading on the rod
Interesting as it is I’m watching from the USA i have no clue of your letter abbreviations any chance for a table breakout of terms. Thank you.
So the PME feeding the rotary isolator is on a RCBO? Obviously that will only protect against short circuit or overload it won’t pick up earth leakage because the CPC Isn’t connected because the rod is being used, does the hot tub have its own DB with RCD?
The RCBO does not reference earth so wont be aware of the missing CPC. It will notice an imbalance in the line conductors when an earth fault occurs.
@@smorty1261 thanks mate 🤙 that makes sense because early rcbos had an cpc fly lead and you had to put in the earth bar of the DB but now they only have Neutral fly lead. Every day is a school day
@@fromthetoon1602 No worries, none of us can know it all 👍. Think some still use the functional earth but I know those CP Fusebox ones don't.
1) In order for an RCBO to comply with BS EN 61009, the RCBO does not have to have a separate (functional) earth connection. However, the standard specifies that an RCBO which has a separate earth connection must behave in a certain way to conform to the specification, but the separate earth connection is not mandatory. There are RCBOs currently available that do not have a separate earth connection, yet they achieve full compliance and conformity with the standard.
2) The functional earth is used as reference by the internal RCBO electronics to increase the sensitivity, speed of operation and allows the device to detect an earth fault even if the neutral becomes disconnected. Losing the neutral connection is rare event, especially in TN systems that are increasingly common today. The probability of losing the neutral and having an earth fault at the same time, a double fault condition, is statistically small and evaluated by some manufacturers as so small not be of significance when specifying protection devices. In spite of this, there are those who advocate fitting an RCBO with separate earth connection “just to be on the safe side”. The penalties for this theoretical risk are RCBOs with taller form factors and the extra connection which make consumer units and distribution boards cramped and harder to wire, pushing up required connection time and costs. Even worse some electricians don’t know how to terminate RCBOs and it is quite common to find RCBOs with the functional earth connections cut off, this is clearly bad practice for a device where the electronics relies on a earth reference for its sensitivity and speed of operation.
3) Most manufacturers of RCBOs with functional earth fly-leads insist that these leads must be disconnected during insulation testing to avoid damage to the sensitive electronics, and during earth impedance loop testing to avoid misleading results. A minority of manufacturers insist on the disconnection of the neutral fly-lead during testing in addition to the functional earth, it is therefore important to consult manufacturers instructions before testing. Removing and replacing connections adds to the time and cost of testing, however, there are other issues. First, there is the possibility of failing to reconnect the functional earth fly-lead, leaving the device operating under conditions other than those for which is was designed. Secondly, disconnecting fly-leads goes against one of the basic principles of installation testing, which is that the installation should be tested in the exactly the same state as it will be operated in service. However, we often break this aspiration in installation testing.
I was inspected yesterday... My inspection guy told me under no circumstances to use 3 core for the tt supply. 2 core... This means the no one can ever use the earth cos its not there to be used. From niceic.
Also... If you step out of the tub on to grass etc then it must be tt. On decking etc no need for tt...
Hope this helps.
Thanks Steve
Thing is next inspector will tell u diff 😂 Just Use Common Sense like I have for last 40 years.
Lol yeah probably. He did email me a a document from nic explaining what the requirements are which is very useful
The inspector from NICEIC are strange always put them straight they make up their own rules, jog on son sign us off champ
So out of curiosity, in places you have to get District Network Operator, approval for a Car Charger, or get the fuse upgraded. So my question do you have to do the same for a Hot Tub, as they can be 32 or 40 Amp draw? An if the house has an electric shower etc surely this could be an issue?
Question
Dose your electric flow clockwise or counter clockwise. Pip. Pip
The go 2 mic is supposed to do the different mics on L and R so you can adjust them separately when you edit them together 😊 (there's another mode that mixes it for you when you are recording but you cant turn Adam down when you do it like that 😉
Why not connect the PME and TT earths together. Then, in the event of a PEN fault, the TT earth will allow the breakers to trip off. Especially important given the presence of a car charger too.
Exactly what I was thinking. Why separate? PME stands for Protective multiple earth… meaning adding more is only going to benefit the system.
So I have a metal shed, to place a cu in there am I better off with a TT or pme back to main cu? I'm thinking TT and bond the shed as well for safety
I've always heat shrunk idetifed all my cables in a consumer unit
Love how the customer has Irn Bru 1901 on the shelve! Legend
and extreme amounts of diet coke
@@Slademoses yeh we don’t talk about about Diet Coke lmao
I was going to suggest ask Dave Savery, as he always seems in the know on regulations. Only other people who I can think would have good opinions would be John Ward and not sure if Big Clive gets involved with household electrics, but I’m sure he’d have strong and good opinions.
I would put the PME earth and TT earth together nowadays the hell with it
I don’t have one of those pray mats to send you, just sending my love sweet cheeks❤️
Why is there a PME in the detached garage anyway....? The PME should not be exported to the external building, so you should divorce the PME from the house inside the garage CU (or just before in a plastic enclosure if the garage feed is SWA) and connect the Earth Electrode to the garage CU, then run this new TT CPC to the Hot Tub Isolator. I would also have put in an Earth Electrode pit rather than that piddly little box as it is in an area that will be walked upon (ran and jumped upon by kids!)?
Is there not a reg that doesn't allow you to have an earth rod within 5m of underground services?
A single cheap contactor can be used to protect against earth faults. Cheap, reliable and a very underrated device. I recon many sparkies won't even know what one is and how it works. No idea why it is not used more in domestic environments.
Explain mate! I’m not an electrician but will have a car charger installed soon and I really enjoying learning about electrics atm!
@@G-ManReviews Car chargers have contactors already installed. Or at least the "good" ones. And none of them start charging without a ground. So you'll be safe. Car chargers don't need any of this crap "separate earth, TT". And if you're using a dodgy charger... just don't!
With a low enough reading could you connect the pme and have an earth rod as back up?. So it serves like your bonding in a pen fault. Or the Tt solution with an rcd main switch and rcbos. belt and braces as rcds fail a lot.
As long as the PME CPC is divorced from the electrode and correctly terminated you are fine, although the CPC isn't protecting the hot tub circuit, it is still providing protection for the supply cable.
Unless it’s a SWA the cpc doesn’t provide protection for any cable . The double insulation provides the basic and fault protection. You could cut a cable and only catch the line conductor.
@@robswingler Sorry missed that it was hi tuff 😳
Adam does take the biscuit dry ,I hope not , keep ere lite 💯
I would of rotated the bin. Or covered it.
Watching John Wards videos Earth spikes need to be placed where they cannot be affected by other underground services, so normally far away from the house or where services can be laid underground to the property.
Silly question and I haven't looked this up, so I'm ready to be slated, but could you put in a PEN fault detection the same as an EV charge point?
I had a TT setup and after rewiring the upstairs of my house myself ended up getting an electrician in to upgrade my CU and rewire the downstairs as work got in the way of my DIY, the Electricain suggested I should have a PME so £167 later and western power have installed one. Still not sure why the difference. My understanding is that as I requested RCCB's throughout my new CU that TT was no longer capable as it required an RCD to be compliant, is this a correct understanding?
How long ago was this. The wiring in property does not change except for earth sizing to main water bond/gas etc. but if done in 10mm to services a pme or Tt could be used. Until the 17th edition came, on a Tt supply a consumer unit could not be in metal unless the RCD was installed before the consumer unit. Meaning minimum 2 consumer units as you don’t want everything governed by one trip. Now you can use a metal clad for a Tt earth system with rcbo’s only as incoming double insulated tails are secured in the enclosure and on the outside of the enclosure
@@f4rducky418 it was done a couple of weeks ago, house is a 1930's build that had a 6mm earth to a spike in the garage and had had some dodgy wiring job done (maybe a home diy job but i suspect a sparky due to number of fused spurs) still had the old 30's rubber wiring throughout the floors which is now mostly ripped out, none is connected so will get the rest out as and when I can.
As long as everything is labelled and segregated correctly I am not aware of any regulation that prohibits the PME and TT earth within the same enclosure. We frequently have dual supplies from alternate sources going in to changeover switches.
PME can be an issue even in double insulated tubs as the water within the tub will be in contact with the extraneous metal work of the pump / heater, so a potential shock hazard exists for some one getting in and out of the tub or whilst testing the water temperature if the surrounding area around the tub is at true earth potential. You can always use the PME with an earth electrode if you can get the resistance low enough and locate the electrode to control the step / touch potential.
Making a lot of unnecessary work, EV charger an Hot tub likely need TT, just TT the submain.
Thanks for the video guys. I have a similar issue im split between. House on a TT going to outbuilding (30m) away. Not sure whether to continue cpc into the outbuilding or to terminate it on a wiska. And run separate tt for the outbuilding, both cpcs would be in the same wiska box. The outbuilding would have a metal clad wall so was opting to separate them. Juat a bit concerned about the two earth potentials in the same enclosure. 🤔. Keep up the good work👍big fan.
Tt outbuilding separately from house and don’t cross connect rods between house and outbuilding.
Funny thing is I always go 2 core SWA for any outside building and the wholesalers always go ( OH 2 CORE ) u sure😂 even on a large office / accommodation building down a garden with shower I ran supply and connected to house and the buildings electrician rang up saying you put wrong cable in so I had to explain to him and he ran a 16 mm G/Y down to the rod😂 I said 10 mm is fine but he could not understand it 🤔🤭😂
yay e550w printer yes but the heatgun ?
regarding the l / r audio you have the wrong rhode cable for an easy edit mate , or the right one if you want to sort it out on post thats the best way dependant on your software
Actually having the 2 mics on the left and right channel is perfect. That allows one to mix their volume independently before rendering the video out as mono. The important part is to remember to either add a mono filter as the last step or to select an output format that has mono audio.
just found your channel. Iam researching because I need my semi rewirerd in side out side and detached garage I realy like your attitued to the job and your skills are great. I live in Keadby nr Scunthope do you have any contacr with a top electrician in my area ? Or ? will you travel and do it yourself ? I want a top job and expect to have to pay for it to be.
Can I have your old wera set (apprentice) ?
Would really help
urm no not reallly I'd just put it on the other side which is I believe a neutral connection that way you've split pme from tt and being in a plastic enclosure no worries of dead short.
Hot Tub and EV charger on a 40amp supply? Im not a sparky, but wouldnt that be a concern, if they decided to get all Hot tubby, while charging the car? Especially on those old Rolec units, as I dont believe they have CT clamps.
well it would just trip the breaker, annoying, but not dangerous
EV charger could be set to lower the current used to charge vehicle when other current using equipment is in use, if that is the set up he is going for
@@aidansymington5204 not on that old "dumb" Rolex unit those didn't have load sharing
PEN fault has always been around but hasn't been deemed important enough until EV chargers / cars came about. So now we have PEN detection devices at affordable prices. Is it worth installing one at the supply end of the installation for peace of mind ? A sepearte TT introduces its own risks, smashing a rod into the ground blindly and potentially (albeit highly unlikley) you could import an earth fault from a neighbouring system through the earth's mass.
Import from america is very unlikely to be class 2... they tend to ground everything or use class zero (yes, really!) Another issue with calling hot tubs class 2 is that internally there are parts that may be earthed to the supply CPC, and the person accessing it is most likely to be a technician on their knees in contact with terra firma, so especially vulnerable to touch voltage. Especially as the PME earth would NOT be disconnected by locking off breakers or the isolator!
Interesting point though, what if you ran all three conductors (L, N, E) through the (typically 3 pole) rotary isolator? Isolating the earth would've been an absolute no-no years ago, but now with EVSEs, it seems to be acceptable way of mitigating the inherent dangers from an open PEN? And then put a label inside the hot tub casing saying 'PME Earth, isolate at local isolator BEFORE touching' ? (TT is likely simpler tho)
Been watching your videos for a while now.
I’m an electrician based in Central Scotland.
Can you tell me where you get your ear defenders you use?
Regards
Robert
Come on Mr bundy the element is metal so has to be class one.. personally my hot tub is connected to a tnc.s supply but I have also fitted an earth rod.. no regs to state you can't connect to a tnc.s supply.. biggest worry lost dno neutral..
Surely the PME is always going to beat the TT in terms of fault current disconnection times if installed correctly so it is just a form of circuit discrimination
The issue is if there is fault in the Supply neutral. Inside the property, things are bonded, you remain protected. Outside YOU become the return path. A real way to ruin your day.
@@brianreay4104 You make a very good point made here but fortunately this installation is in accordance with Figure 7 / 8 of the Guidance Notes: electrical.theiet.org/media/1698/earthing-your-questions-answered.pdf
What about if we want one of your Matts tho 😮
Mate I’m from macclesfield I’d have nipped down to say hello! Love you and Adams content!!
What happens to the isolator if the door swings wide open in a stiff breeze ?
Thought the same 🤔
Already checked bud 👍 the hinge only lets it open a certain amount , about 2 inches off the iso 👍
@@NBundyElectrical figured you'd be on it 👌👌👏👏👏🏴
where do you get the work matts?
2-3 minute mark, you've left the customers address on the bin ;)
I assume we generally TT permanent outdoor things due to the (albeit rare) possibility of a DNO loss of neutral thus making PME earth live. Is this correct?
If so, why don't we just bond the supply earth with an Earth Rod at the supply (meter) box, thus future proofing the whole house for other outdoor things (eg car charger). It means future outdoor devices wouldn't need more earth rods.
It also means you could still rely on PEFC for ADS during normal times, and fall back to RCD if there was a neutral fail.
My understanding is that this would still be a TNCS supply but now it would be "TNCS with Earth Rod"
Maybe we're not supposed to bond PME and TT. But why not?
Thoughts?
(Please, do not take the above words as any advice, I'm just thinking out loud)
Where u guys from…you said your in congelton ? Cheshire ?
Stafford mate
Have you asked John Ward or Big Clive what they may know?
Great work and thanks for sharing this with us take care
Hi Nick/Adam if your wrong with the tt/pme system, so am I
What's the amazon link for the heatshrink gun Nick?
Check out this Idea List on Amazon: Useful tools for a spark by N Bundy Electrical amzn.eu/1e1wXnr
Hi Nick. I don't normally comment on video's like this but as I'm sure your aware the hot tub falls under the requirements of Section 702 (Swimming pools and other basins). There really is no issue taking the TN-C-S earth (PME) out of the building and using it. As a general rule you should make sure the earth conductor is the same CSA as the protective bonding conductors so 10mm typically in a domestic environment. Creating a actually TT system is quite difficult. People tend to just bang in electrodes anywhere. In reality if that electrode is within 5meters or so of metal pipes in the ground or other metalwork which are connected to the PME system its not really going to be a true TT system. The issue with using PME outside is that a failure upstream of the PEN connection could mean that exposed metalwork connected to earth could become live, hence why people TT things. My view is that your ok using the PME earth but install an earth electrode as well. So ground out at the consumer end the earth conductor. Regulation 702.410.3.4.3 (ii) describes this. Also make sure you keep your isolator at least 2mt from the hot tub so Zone 2 minimum. Obviously the circuit must have 30mA RCD protection. Your earth electrode resistance should not be more than 20ohm
Can I ask where the 20ohm comes from please?
@@michaeldavies1755 Hi. If you look at the reg noted its stated there. Difficult to achieve even with using multiple electrodes or tape/mats
The new amendment recommends adding a TT spike into any existing earth system now anyway.. so... its a bit of a mess.
Who can afford to run a hot tub in the present climate anyway? Only electricians
Sorry if Im unclear on the subject but what in layman terms is the problem with conencting the two earths together?
Thanks for another excellent video Nick.🖖
A lot of homes have a PME earth, which really just means the earth and neutral are connected together at the supply, under some failure conditions the earth can end up live, inside a property the consequences are limited as everything is bonded to the same potential, outside you could come into contact with true earth.
The issue is that, in a PEN fault situation, your earth spike may be the best path to replace the broken neutral for the whole neighbourhood.
@@HenryLoenwind No experience of PME as I retired from electrics many years ago. I used to try to apply three Grounds at domestic installations,
1) Board input cable outer sheath,
2) Water main pipe - did not have plastic in my day. 😊
3) My own installed copper earthing rod which I understand is now called TT.
It's strange to learn that Grounds now have to be kept apart due to PME,
I can now understand why Nick is applying a separate copper earthing rod just to the hot tub. It does beg the question (from an old timer) 'What if the water somehow became live with no path to Ground inside the hot tub?'
It probably would never happen? Then again, who wants to fit an expensive isolation transformer just for the tub.
I like his bicep 🤣🤣
What about trying the hot tub that must be a part of the testing 😂😂😂
Interesting discussion topic of PME or TT debate.
Can you show us pictures or video of the incomer/cut out arrangement?
This could then be referred to when people look at BS7671, People should also look at the free information by DNO's like ukpowernetworks who have a range of free document which will help. For example EDS 08-2110 shows what can and what cannot be in a meter box.
Another good point of reference is the ENA (Energy Network Association) they also have some free documents which can help. A very insightful document is called
Distribution Network Operator Cut-out Types & Ratings Guidance
Keep up the good work guys
Have you checked the specs for the hot tub if its from the States. It could be 240v line to line and not 240v line to neutral as in the UK?
That usually shouldn’t matter. As it just sees 240v between phases only issue is if it’s wired for 120v control circuits if wired American 240v three wire with a neutral