Broken PEN conductors and Diverted Neutral Currents - How to check for and mitigate them
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- Опубликовано: 24 сен 2023
- Lets take a look at a 3 phase service head and the combined neutral and earth conductor. In this casing checking for and understanding both circulating network currents and diverted neutral currents.
This is not a new phenomenon and has existed since the 1930s in places. The wiring regulations and DNO providers take account of it during design and maintenance.
I take a look through process to test for it, BS 7671, GN8 earthing and bonding along with GN3 Inspection and Testing.
Its really important we acknowledge the low probability of PEN faults combined with the multitude of other network derived issues. But equally accept and understand the dangers when it does.
Please check the John Ward referenced video here • Diverted Neutral Curre... which sets the issue out brilliantly.
When industry is faced with huge issues like basic trips, slips and falls, travel to and from work, stress, metal health, training, skills, jobs etc. Its easy to overlook the micro and niche issues. Equally it pays to be aware of them, I acknowledge this is a well discussed and understood concept among electricians so this is primarily shared for new entrants, trainees and apprentices.
I have shared loads around this probably for a decade and more so sorry for repeating a message many of you might have seen before.
Please get involved in the comments!
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Really great watch .as a retail testing and inspection engineer. .it's always something easily overlooked
JW’s explanation is excellent.
Absolutely it is!
Niche and rare subject but knowledge for those who don't know is great.
@@democracyforall I think you need to watch the video again. I am not sure where you propose to place a diode. Re think
@@A121podcast This system has been in use from the start of electricity did you now that??? The nuetral has to take the current back to the earth or not?? IT HAS BEEN LIKE THIS FOR OVER 150 YEARS HA HA HA. But recently they brought it all the way to the tail of house meters etc... Is this new??? No , people do not know this so when did it became a problem in 150 years?? Never because where it is earth all the way to the main supply outside they have a protection system as I said it was not design by electrician but by phd engineer and that is why it worked. Now , the other guy is going round and round trying to prove there is current on the earth, first thing he should look a the other system earthing attached to big walls in many buildings -like the one in BBC building and National Audit building, then he should explaine where there is power on it, the he should explaine why it is not tripping the RCD? Because it is leakage current that goes down all the way to the baily of the earth or to a wall in a big buildling as it is additionall in BBC building and National audit office. So why it does not trip the RDC then??? 2nd this is the system in use for 150 years, if you use your own supply where will you earth the nuetral?? Of course you will to take it down all the way to that earth rode or not, if there is no earth rod the electricity does not flow , it will rotate a small amount if it has to flow to the earth this has been the case for 150 years and on the supply side they have protection from going back to house holds because they are dealing with big current and voltage and so far it has worked. If there is power on the earth line and someone think they are clever then work it out why the Bloody RCD does not trip??? and why it does not trip the RCD and other system on the supplier side?? All I see is people with little knowldge trying to be clever that is all I see which is total ignorance....
Thanks Mark you contributing very topic subject to let us know👍
Another great and informative video Mark.
Cheers Sergio. Something I've meant to share into A121 for a long time. Covered lots on my main channel and elsewhere
@@A121podcast 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 revealing 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.... because people are looking at the service head and imaging reverse power no not here at the other hand there is protective system that does not allow reverse power....
Brilliant summation of the current situation Mark! More of this kind of talk. Yes the knowledge and guidance is put there. But how much could BS 7671 do with their changes. Their guidance has mentioned this as best they can as you stated but is this a dno? Water? Gas? Issue to address? I don't know at the moment. But I will get to the bottom of a solution one day. 👍.
RUclips is shit. Won't let me edit the put into out.
Non contact voltage indicators are best suited for polarity testing, brilliant info, great explanation,
Lots of useful information, thank you ☘️
I have a question which is now concerning me, is it safe to use a copper pipe in the floor as an earth while still being attached to these weird combined systems?
Our garage has spent the last 25+ years with a separate earth without problems but the house had it's own small cable earth rod system put in to reduce noise on amplifiers, now I'm worried it might be a fire hazard.
The DNO can neglect their responsibly towards maintaining TNCS system earthing
There examples in numerous other industries where maintenance has been neglected.
What about installing loss of neutral monitoring at the fuse head intake it’s self with Ze monitor that sounds a warning if the value rises above 0.35 ohms?
Yes Matt:e have a cool product for just that. Client cost though rather than DNO. Still I would say its worth it!
Does this unit have a steel frame that's shared with another unit?
Yes and they are all bonded at each individual service head in every unit.
I hope the armour is steel not "aluminium in nature" - hence the definition of SWA,
Steel Wire Armour cable, which should not be the Neutral conductor, by the way !!!!!!!???????
I take it you are unfamiliar with DNO distribution cabling. This is a very common cable type where the outer strands are used as a conductor.
CNE split concentric with a combined N-E on PME systems. Google is your friend if you are unfamiliar with it. Thanks
@@A121podcast Thanking you, however as an elec. engineer. I am familiar
with split concentric cable. With the ones which I have dealt with half of the
outer stands were black insulated copper for the neutral, the remaining half in
bare copper for the earth. It is difficult to tell in the video colouring if you have
zinc coated steel or aluminium. Thanks again.
DNO do NOT use SWA for services! It is AWA.
@@posei3960 100%