Diverted Neutral Current Demonstration - Normal, Open CNE, Current Circulation (Part 2)

A demonstration of diverted neutral current using a 12V AC test rig. This represents two adjacent properties with TN-C-S supplies via a CNE (combined neutral and earth) cable and a shared extraneous conductive part.
Demonstration includes:
► normal operation
► current sharing between the CNE and bonding conductors
► what happens with an open CNE in one property and not in the adjacent one
► the situation with more than two properties all connected to the same extraneous part.
In all cases, current can be found in the bonding conductors connected to shared metallic parts such as gas or water pipes.
Note that this demonstration uses a custom manufactured test rig which runs on an isolated 12 volt AC supply. Some of the items shown would be dangerous if done with 230V or a real electrical installation.

[@mb-electricalservices]

Acacia Road......Bananaman reference? God I loved that show as a child! 😊You're a legend and inspiration to us all John. Thanks for the much valued content! Mike.

[@democracyforall]

I think it must be either a mistake or the Electrician may not be informed??? I am sure that they will have a diode connect to the earth so no voltage or current finds its way back, I am pretty sure that is the case, why would someone design something as bad as this?? If you were to connect a diode to it , it will not allow any current or voltage, thus it can flow into it but not the otherway around....And if there is a diod connected to it not to allow the reverse power etc, you can sitll be sure that all earth in a big building will have power as allot of it is flowing to it from leakage current etc, in building where it is no PEN SYSTEM ANYONE DARE TOUCH THOSE BIG EARTH WIRES, THUS THERE IS A PROBLEM IN THE EXPLANATION HERE... UNLESS some one was so stupid that he was totally blind to design a system like that, which I do not belive it is the case, inside that box somehwere there has to be a diode to make sure it does not allow revers power, but all other power on the earth in all system is commong it is leakage current and it is in all building not just for PEN system....

[@electrician247]

Lots of time and effort gone into that rig John. Well done.

[@Swwils]

Everyone else better step it up 😂

[@andyrobinson6052]

I have now watched many of your videos over the last few years and must say that you, sir, are a truly excellent communicator

[@user-ju6kx5hp1w]

Just when I thought I'm finally reaching a understanding of why and whats happening. You say "your only scratching the surface and 3 phase is more complex". Excellent demonstration, thank you for your time and effort that goes into making these videos. I've learnt so much from you. Your 1 of the greatest minds in our industry.

[@DavidWilliams-zw2ji]

This is the best explanation of the topic that I have ever seen. Many thanks for the time and effort making your videos.

[@steve83803]

I spent over 10 years working on the distribution networks and dropped neutrals caused everything from all electrical appliances in the properties failing (spectacularly if on different phases) to dead livestock, electrocuted Koi carp and several house fires. Great clear and concise video.

[@democracyforall]

Then why is he afraid to remove my comments??? Think about it the system of PEN was designed by who?? An electrician or a phd engineer? Of course it would have been someone with phd so why would he make such a big mistake???? The system does not allow revers power did you know that, there is diode on the end of it with other protective system not to allow reverse power and john ward and others are going around revearling themselves ha ha ha ha. I have worked in all big buildings like BBC , National Audit office ITV TV building all of them or not PEN system and do you know how much leakage current flows to the earth in those building?? Anyone touching those earth rode will end up dead.... and it is nothing to do with PEN... Now do not remove my comments neither praise me but be thankful for learning....

[@maxmerton]

I’ve been guilty of disconnecting main bonding clamps from pipes in the past, and not giving it a second thought. This has opened my eyes!

[@skamuk1]

Thanks for this, very informative. Something to point out, even if you don’t have any current on your bonding conductor when disconnected at the time of testing, that’s not to suggest it doesn’t suddenly become live when someone down the road comes back from holiday and switches stuff on! I treat ‘earthing’ conductors as if they are live at all times, easier to respect it than be a victim! Thanks again 👍👍

[@stanleyadamson912]

Hi John thanks for this video. I work in a quarry and one time after an electrical inspection , it was the next day in fact the asphalt plant operator called and said the plant was acting strange, various things weren’t working and some items had tripped. Anyhow I went up for a look and discovered very strange voltage levels at various points in the electrical panels. I eventually traced the problem which was in a three phase distribution board in the next building. The insurance inspector had disconnected the numeral conductor while testing and he never re-connected it. 🤦‍♂️ As you say the voltages across various circuits varied like crazy. It’s a wonder something didn’t get damaged.

[@PardoeElectrical]

People ask me "is there any KZbin videos I can watch to help me learn about electrical theory?" I say watch John Ward. Very well explained 👏

[@mikenco]

I emailed John. Rest assured, he's simply busy with paying projects! He says he'll be creating new vids soon.

[@gbelectricks]

Perhaps we should all start running on 12V🤔😁 Joking aside you’ve successfully highlighted a very serious problem that will only become more prevalent over time. To truly test for dangerous voltages on disconnected bonding conductors (on a compromised system) we need to reference/ test it to true earth, meaning we need to put a temporary test rod in the ground far enough away form any of the properties in the street!! Who said TNcS was the best earthing arrangement?😃

[@dave-d]

I remember the first time an engineer from our local supply company said "It's all PME now" and thinking do I trust a remote earth connection managed by the DNO? And here we are! Great work as always John. You are an asset to the trade. Thank you.

[@jjimmyrjagger]

Brilliant the way you describe things clearly and in a understandable way , love you videos 👍

[@davidchamberlain2162]

A very informative demonstration as usual. I only vaguely knew this. Seeing this practical explanation was fist class.

[@warrengray610]

Greetings John, another great, clear and concise explanation Also very handy use of transformer ratios to lower the voltage , increase the current but safely show the principles,, Very well presented,,, I bet those lamps were getting hot! Thank you for this!

[@peterrobinson850]

Hi John, From an old spark from the 60's. An excellent tutorial as usual, you definitely put some work in to that rig for the benefit to others, I applaud you. I often thought of this scenario and tried to visualise that having water and gas pipes buried would act as very effective earthing rods at the same time effectively parallel paths conducting current to the neighbours and also carrying current back to the substation at the same time thus would mitigate the need for a separate earth rod for safety to limit the touch voltage, please correct my if I'm wrong perhaps my 75 year old brain is defective also. I wait with exited anticipation for your next video, your and excellent communicator. Peter.

[@joken8901]

your right the water, gas, and lead sheath on the incoming supply gave you a good earth untill the suppliers changed everything to plastic IEE REGS says it all how many times have they not got it right....obviously everything doesent go back to earth so fit an RCD as close to the meter as you can this will keep john out of your house as he seems to be more interested in whats going on in the neighbours house, mabe they fitted their own meter, and mabe john is colluding with the cartel to take the rest of your rights.

[@fyberoptyx]

Excellent tutorial as always John

[@bluebellelectrical]

Fantastic video John. I knew the theory, but actually seeing it in a realistic installation, it now all makes perfect sense. Thank you.

[@warrengray610]

That's very true there's only so much you can visually see in your brain,,, but when it's presented in that fashion it really does make sense

[@timballam3675]

Had our gas meter removed. The meter guy had a big red "jump lead" to put across the meter during removal!

[@peterswinson326]

Excellent video as ever JW, probably an issue that will happen more and more commonly as the network ages and not something electricians are necessarily going to be looking out for, can't wait for the horrifying 3 phase episode :)

[@warrengray610]

Give the man a day off he's already done the rig for the single phase,,lol

[@jam99]

Then again, in some dwelling/building situations, utilities are going more and more to plastic pipes all the way and so perhaps reducing the overall alternative return path impedance. But then some retrofitted plastic pipes are being fed up inside the existing metal ones (e.g. gas) so you probably still have bonded metal going into the ground. Perhaps even the water conductivity in plastic water pipes can become significant in neutral disconnect fault situations if everything is plastic? As a home-owner, I guess the lower the chance of other dwellings 'helping' with your circuit return in the fault case that just you have a disconnected neutral incomer, the more likely you are to get a shock situation but also the more likely you will find your appliances going 'crazy' or not working. It's a tricky bugger. Definitely worth checking the current on as many bond wires you can clamp around and measuring the potential between the two conductors of any 'earth' connection you disconnect before touching.

[@ramzg5402]

Hello Mr John, thank you very much

[@thomasfny]

As a mature sparky, learning doesn’t come easily 🙈 I would like to both thank and congratulate you on your 2 videos on Diverted Neutral Videos 👏🏻👏🏻👏🏻👏🏻 It explained the subject so, even old “f” like can understand it. All Gas engineers, should be made to watch them! Then they may actually use the lead in their tool bag when they remove meters, instead of a jump lead for their cars! Many Thanks Thomas

[@garyedwards5955]

Very interesting came across this recently when the gas board damaged a supply cable while digging. I have a lovely video sent to me by the gas fitter of the spark on the gas pipe lol

[@fimbles1015]

Amazing video. I would never have even considered this. you turned the principles in to a clear concise demonstration.

[@fje1948]

What a precise and accurate explanation supported by a superb demonstration, much appreciated. The test setup must have been a lot of work! Thank you John.

[@chriswilson7493]

Excellent demo, as someone else mentioned obviously you have gone to a lot of trouble in order to create a great explanation, many thanks JW!

[@godfreypoon5148]

Another good down-to-earth explanation. Thanks, John.

[@andyb7813]

Great presentation John and thanks for all the hard work you put into it

[@CNJNSftw]

Another fantastic explanation John on a subject a lot of us don't know enough about. Brilliant work on the demo rig!

[@cliveramsbotty6077]

thanks john this was very helpful and informative. i'm a gas man, electricity is weird. i struggle to get my head around it.

[@terrysteel6706]

Incredible opens your eyes to what dangerous situations can arise due to a lost neutral or broken connection

[@speedbird300]

Bloody excellent

[@tomthomas8013]

As always JW excellent explanation with the fault paths and great effort on the rig, looking forward to the three phase horror show!

[@tubaman66]

Very informative. Makes my TT installation feel like a good thing!

[@haldo691]

How do you know its TT all the way?

[@tubaman66]

@@haldo691 No connection between the incoming main and the house earth, which is a staked rod. Water main is plastic and no gas supply, so no metallic connections to another property. Not sure what else to say.

[@pjeaton58]

@@tubaman66 And is the water in a plastic pipe a conductor ????

[@tubaman66]

@@pjeaton58 it'll be a pretty rubbish conductor over anything but a very short distance.

[@9111logic]

It was a very interesting and educational lecture for us all, so thank you very much for setting it all up in such a brilliant way. 🙏

[@binky_bun]

This has been very informative. As a ham radio operator the one thing I struggled to understand the most when I took my test was grounding and bonding. I remember learning about the different earthing configurations such as TN-C-S and I remember a situation being explained to me where if you have a really good low impedance RF grounding system you can run into issues where your RF ground ends up sinking current for your neighbours which can lead to an unsafe situation either risk of electric shock or the high currents melting your cables and burning your house down. I believe this is pretty much the exact same scenario but explained much better. My old house was TT a system with it's own ground rod outside which I seem to recall as being much less risky however it was made dangerous by some metal thieves who decided to steal the 8 inches of cable from where it came through the wall to the top of the ground rod so I had to replace that at one point. I now live in a house with a TN-C-S system and after moving in it needed a lot of work on the plumbing and we replaced a section of metal water pipe just after the service entrance with plastic but that was before the bonding so we added a cable to bridge the plastic part but as someone doing a bit of DIY plumbing I had no idea how dangerous that could be.

[@nickdunstone]

Excellent! I look forward to the 3-phase one!

[@icarossavvides2641]

Very interesting and well presented. I think this has explained a problem with a friends boiler installation AND a problem with contactless voltage sensors. The boiler had been reinstalled in the loft space. When the gas service technician checked the boiler with his contactless voltage sensor, is flashed and bleeped, as did mine BUT when probed with a DMM NOTHING showed! Just goes to show that all these expensive ELCB's, RCCB's etc are absolutely useless in this fault situation!

[@TechOne7671]

Brilliant demonstration and rig, a lot of thought and time has went into building what is an excellent experiment. Can only imagine the calculations on a three phase system with say 20 houses, the variables and voltages would be infinite. Reminds me of college exam problems. All the best.

[@EXFElectrician]

Great Video clear visual representation of what can happen

[@stevedunthorne7376]

Superb teaching 'manner' and speed. KZbin needs people like you, JW. Thank you.

[@bostedtap8399]

Excellent tutorial, impressive setup John. Thanks for sharing

[@garthdowie9147]

Thanks for taking the time to produce this very educational video . Every day is a school day !

[@M8d9R]

Excellent video, helps alot trying to get your head around this. Real world scenario is going to be alot more complex, quite daunting.

[@paultutton9443]

I hope that all's well John. Having learned so much from your KZbin content I have my fingers crossed that it won't be too long before we hear from you again - your clear explanations and dry humour are much missed! Best wishes from just down the road in Dorchester.

[@eddiefitzgerald5198]

That was a very interesting and informative video John. Thank you.

[@deancleaton3967]

Clear and concise as usual, thanks.

[@dudleyguy42]

Brilliant explanation John, very good rig a lot of time and effort put in, well done * * * * *

[@michaelcostello6991]

Great subject explained as simply as possible

[@alanbeard4871]

Great Video, made me realise that just checking for currents in bonding conductors isn't that informative and disconnecting a bonding conductor is more risky than I thought. So I have learnt something but now feel even more confused about the subject. But it does show that bonding to a pipe that isn't actually connected to real earth substantially increases risk in open pen conditions. Sounds like the only safe way of doing things is to make sure no one is going to touch anything, disconnect and measure voltage to real earth. Given there are about 400 instances of open pen a year, about 0.002% of houses I wonder how many will actually make these checks.

[@williammartinculleton5875]

JW at his best, thanks for your time, effort & expertise in producing this excellent presentation ☘️🇮🇪☘️

[@highgatehandyman6479]

I watch all your stuff John. Top bannana. Ill be able to self certify soon and truth is these videos are a valuable resource for life long learning.

[@bazboy24]

This is an eye opener for sure

[@TurboTel68]

Brilliant rig John! Such a useful and well thought out training aid

[@ianbrede16]

Thanks John, excellent part1 but your marvelous demo jig shows how complicated diverted neutral currents can be.

[@Graham_Langley]

Good video John. Been an electronic engineer most of my working life so spotting the effects of a broken return connection are second nature. I had considered the effect of a broken neutral here as it has a looped supply, but the water supply is in plastic and there's a galvanic isolator in the incoming gas main so no parallel paths.

[@Graham_Langley]

Correction: Well there was a galvanic isolator on the incoming gas main but it's not there now. Can't find any pictures but you can clearly see where it was as I couldn't paint the wall behind it. Must have been removed when the regulator was changed in 2009 and I hadn't noticed. FWIW the gas supply is in plastic but changes to steel before emerging from the garage floor. They no longer allow joints like this to be underground and I wonder if this video's topic has something to do with it.

[@pjeaton58]

And is the water in a plastic pipe a conductor ????

[@blower1]

@@pjeaton58 Not enough of a conductor to be of any concern. Resistance of water in a plastic pipe over just a metre is so high that it won't conduct any appreciable current, let alone the distance to the next house.

[@Graham_Langley]

@@pjeaton58 John's done this in a previous video. The answer was no.

[@pjeaton58]

@@blower1 Really ? Well I won`t be intentionally touching a metal tap on the end of a plastic pipe fed from a water heater where all ground integrity has failed. Perhaps JW would like to construct a demo of this scenario to prove that it`s OK this time using the full 230vac with 30ma RCD of course !

[@dstat79]

Wow that’s actually quite scary! Thanks for making this video, definitely something to be aware of 😱

[@deancook2123]

Cheers JW great insight into this new electric blind danger - many thanks again 👍

[@TheMadMagician87]

Thanks for the effort to build all that, and for explaining it all and putting the videos together. Very informative!

[@cestemshow]

Great effort John. Great demo. Very difficult to calculate this stuff. So many different scenarios to deal with. Safe working Procedures will be easier to create than trying to calculate whether it's correct or not based on measured values at properties.

[@stillstanding123]

Step by step, methodically explained. It's an excellent training video. Love the shirt too 😊

[@cambridgemart2075]

We lost neutral on an expensive piece of equipment running on 3 phase 415V, the smaller loads, i.e. all of the control electronics, were wired between a phase and neutral and some of the medium loads like motors, pumps and fans were running from a different phase to neutral. When the equipment was switched on, the electrical cabinet emitted a great deal of smoke!

[@markr9069]

Thanks for the great video and the amount of effort you've put in to build up such a great demo

[@Adam-tn7yk]

thanks for all the hard work you put into that jig. much appreciated as always.

[@chrisccs2112]

Brilliant video John!!

[@dieseldragon6756]

As a hobbyist electrician/DIY'er, I keep forgetting about the potential alternative return paths in the average installation, so many thanks for the reminder _and_ for explaining the potential dangers these can cause! 👍 One thing that worries me on seeing this - Given I live on a street with TN-C-S fed Economy 7 - Is that the typical earth bonding conductor is only about 5-8mm² cross-section versus the 25mm² tails for line & neutral, so the potential (Sorry! 🙃) for other installations to back-feed their whole neutral through my earth bonding (Which I estimate might fuse at perhaps 100A) if their N fails scares the heck out of me. ⚡🔥😨 There's a part of me that's tempted to install current monitoring coils on some of my bonds just so I can monitor for faults and spot any serious danger signs early enough to raise the alarm. Like you said the mere presence of current in these isn't a concern in itself (I mean; 5A paralleling through my bond isn't likely to cause a serious risk) but if a typical 5A flow suddenly jumped up to 50A and stayed there that might pinpoint some damage elsewhere in the system. ⚠

[@johnburns4017]

You should fit full RCD protection, preferably RCBOs on all circuits with AFDDs on socket circuits, as _recommended._ Then disconnect any earth cable clamped to gas and water pipes. That will isolate your installation from next door. Well not quite. Depends. Next door could have a fault sending voltage and current down an earth cable then through the shared metal gas pipe into your house. This will make your gas boiler live and also your electrical system via the boiler's supply cable as it is earthed to the boiler's metal. So best have all or most of: *1)* plastic gas a water mains supplies. *2)* TT earthing *3)* A main whole house RCBO switch (disjoncteur différentiel) *4)* Double pole RCBO or AFDDs on each circuit.

[@GaryCram-l3b]

Hi. I just watched one of your other videos that shows exactly how a 3 port valve works. The one with the lights showing the flow. Nice video which clarifies something for me. The reason I found your video is because I am in the process (tomorrow) of replacing a Switchmaster 400 with a Tado Wireless receiver. I did this before in another house so have some familiarity. Although that system uses 2 separate vales for the hot water and heating. The system I am installing the receiver to tomorrow, has a hot water cylinder in the airing cupboard, small tank in the loft for the radiators while the cylinder is fed from the large cold water tank in the loft. I think this what you call a gravity fed system (I'm not a plumber). The thing about this system however, is that the controller only offers the following configurations: Hot Water only or Heating and Hot water. But, NOT Heating only. The switches on the controller literally says this so I know it's not an issue with the valve. Which by the way is a Drayton Mid Position (it says MA1 on the unit). This controller I think was installed in 1970 and I have no idea why it could not have been installed with a controller that gives all valve position (Hot Water or Heating. Or both). Ok so here is the issue. According to Tado, once I have followed their instructions, the function of the water flow valve will not change. Basically keeping me in the same situation as before. Can you advise me what I need to do in order to get all valve options on the Tado. As in, should I get a plumber/electrician to just re-wire this ? Surely this should be very straightforward. What do you think ?

[@antonyharding5360]

Well done john , Regards antony,Warrington Cheshire..

[@waynestares6512]

Thank you John. Your videos are brilliant. All the best.

[@LoftInsulation-pj9dj]

Props to JW for taking his time.

[@robertstopford1016]

Brilliant content as always. Love the funky shirt. Keep up the great work John!

[@nicknorth360]

Excellent video John I could show this to my students. Your rig is superb

[@clivequinn8978]

Thank you J.W., excellent video, certainly an eye opener.

[@TheBigstve]

Lovely John. The issue is serious, I think personally all new homes should have the earth electrode being connected with the MET of the TN-C-S as stated a recommendation in BS7671 to help this cause. So many electrical contractors are unaware of the above.

[@okaro6595]

An earth electrode is like taking aspirin on toothache. It does not to that much,

[@oasntet]

I love this demo. So easy to follow. If you can't know ahead of time whether there could be a voltage on everything bonded to earth in the house you're working on until after you disconnect the bonding wire, how can you do that most safely so random residents in the house don't get shocked from trying to wash the dishes? Is there another tool you could put across that bonding link that would alarm the moment the voltage appeared and preferably re-link that connection to prevent shocks?

[@Mainly_Electrical]

@mainly electrical , youtube, to learn my friend

[@willrobertson7778]

👍👍👍Definitely the best explanation of this that I've ever seen! I was thinking about how to set up a demonstration of Diverted Neutral Current in a 3 phase system where only a single phase supply is available to run the demonstration - I think I've worked out a way to get an isolated low voltage 3 phase supply from a single phase input with a reasonable power capacity at reasonable cost - let me know if you're interested. Would be great to demonstrate with safe low voltages some of the weird, wonderful and lethal things that can happen with Diverted Neutral Current in a 3 phase system.

[@planetpeckham1]

Round of applause! Much appreciated

[@philippuszka7356]

Thank you very much for an interesting demonstration! Great explanation.

[@julesviolin]

Amazing demo . Never assume anything ⚠️ Always Test 1st

[@grahamwise5719]

Hi John, the close where I live in the past the neutral of the 3 phase supply broke, each house depending on the balance of the phase loads either had high or low volts. Many appliances were damaged and repaired free of charge. I now have a earth rod in addition to the supplied neutral. I suppose if it happens again all houses will be earthed by my rod! What about the my house TNCS where the supply cable is lopped out to another house. The water and gas supply here are plastic. thanks for the demonstration.

[@timballam3675]

Fitted my own earth rod when we were un looped by national grid. Water on plastic so should be good now gas removed.....

[@2lturbo]

Through the magic of buying two.

[@doublebass5y]

Great video John. Surely this just goes to show that PME systems are shit and supplied because its cheaper. Also reason why its not allowed i believe to supply petrol stations.

[@christastic100]

Very useful demonstration and brilliantly made test rig . It shows is a very strong reason and argument for TT arrangements being preferred for metal services such as gas or water. Makes me wonder if it should be considered as a regulation requirement for all metal service properties to be only TT or TN -S perhaps.

[@maverickdisco4036]

Excellent presentation, my “I’ve learned something” for today. Thank you for your time and considerable effort into putting this together.

[@sergiofernandez3725]

Fantastic video John. Would a smart meter pick up on the broken neutral or not? What about a buried phone cable into the property, could that carry Amps to another property? Also with some coms cable, Could that be connected to a differnce power source (transformer) in the next town along thus using different Supply&Earthing characteristics? I am looking forward to the next episode

[@jwflame]

Meter won't detect anything, as it's just connected to the L&N conductors after the CNE cable is split. Even with the CNE totally broken, current in the L&N will be the same, which is also why RCDs won't trip either. On top of that, meters only measure current in the line conductor, the neutral is a solid link internally.

[@Michelle-jc7dj]

Fantastic demonstration, love your videos.

[@timbell5676]

The solution is if possible to avoid using PME or combined Neutral earth, and stick to a independent earth/stake with RCD. while the underground supply is more reliable, a overhead system is more prone to the neutral failing on the crimped connection on the overhead and I;m surprised that it is still allowed. Their are many example of where PME or combined earth/neutral is NOT ALLOWED. Outside water taps can be dangerous too, where many plumbers do NOT use plastic or insulation between tap and copper inside plumbing! Thank you John for an excellent video!

[@okaro6595]

RCDs can and do fail.

[@johnburns4017]

@595 The French do not have a main fuse. They have a main whole house 500ma RCBO which doubles as the main switch. They also have normal 30ma RCDs in the consumer unit. So if an RCD fails in the CU the main RCBO catches it. Much superior to the nonsense in the UK. These are available in the UK. About £60-80 to buy. Called _disjoncteur différentiel,_ made by Legrand branded Baco. A search will bring them up.

[@adrianshingler9783]

Great video from a total legend, thanks John! I’m off to buy a clamp on ammeter 😎👍❤️Update with the new ammeter our 45A instant shower gave rise to around 1A in our bonding conductor, will be interesting to see what happens around peak time 👍.

[@antelectric8554]

thankyou !, wonderful demo and good use of clamp meter as a extra safety test. Dropped neutral thankfully is relatively rare in the UK..... about 100 fires a year I believe......not bad out of 30,000,000 homes. ........but day in and day out I see poor quality main earth bonding connections, ....WHAT EVER earth is available [...could be some strange item , like earthed electric lathe in an outhouse, if pipework to property PVC for example] takes the full load potentially if neutral lost...so that crumpled old loose fitting clamp on an oxidised pipe............. main earth bonding quality really important

[@stuartthespark]

We could say that electrical testing should now take place each year to confirm a healthy PME system, similar to a gas boiler check. A basic check on the integrity of the DNO supply that should be mandatory.

[@mastergx1]

Very nicely done. I love the rig with ELV AC. I've never liked the idea of PME because of this possibiliy (what was wrong with TN-S!?). I've never had a broken PEN conductor before but I have had a broken phase on a 3-phase supply (L3 I think). Just making a point that they can and do fail - even though it is rare.

[@okaro6595]

TN-S is expensive. Also it has a problem with possibility of broken PE. This in itself does not cause any harm which is the bad thing as it goes undetected. Then if you get an equipment failure you get shocked.

[@ollieb7394]

Brilliant video as always, cheers John

[@descultualexandru4022]

Looking forward to your next video. Thanks for this one

[@rossmurdoch7870]

Another brilliant eye opening video explaining a pretty complicated and possibly lethal situation, which will in fact be common throughout the UK. I would suggest most electricians will not know too much about. This video should be shown to anybody who works on domestic electrics, and crucially Gas and Water pipes. There must be several fatalities stemming from this diverted current situation. The most worrying thing its dangerous almost by design. TNCS is a pretty poor arrangement really considering the parallel paths through connected and bonded pipework in the streets. Should we reconsider the our Bonding practices or install plastic pipework as it enters the property as standard?

[@James_Bowie]

Excellent demo. Did you install resistors into the water/gas path pipework to create those different currents?

[@jwflame]

No, that's purely due to the different lengths of wire and the difference in resistance between the wires and the copper pipes.

[@Mike_5]

It has to be said JW that is a very very impressive test rig you have constructed there!! Hopefully that is a copper water pipe cut off there not a Gas pipe though?

[@ashvanbro9329]

Great rig john great work like always mate

[@lordofelectrons4513]

Very good video. A very dangerous failure mode and arguably a significant design error.

[@reneradojcic]

Magnificent content, thank you!