Exporting Pme 2016-09-21

[MDJ]

I'm glad someone thinks so ?

well one person at least ?

 

[old man sparky]

How can you Code the loss of a PEN connection when no mention of this is made in BS7671. I really don't get people's obsession with PE

How can you Code the loss of a PEN connection when no mention of this is made in BS7671. I really don't get people's obsession with PEN losses.

Agree coding is a non starter as said (I wouldn't) You cant start coding based on what may happen if PEN is lost. The C2 scenario was just by example of where and how far do you go, and where do you stop. Although why are there now increased sizes in main earthing and bonding conductors where TNC-S is used , maybe there is something in BS7671, maybe in time it will go further. There are a lot of regulations in the 18th that didn't exist in the 14th per say. So just because its not in there doesn't mean it won't be there in future editions. There is a potential danger with a lost PEN. If you were on the receiving end of a 230 volt live conductive part I think you would probably be a little concerned.
And I think the discussion on this thread comes from a place of concern rather than obsession. EV charge stations are rapidly on the increase, and with PME being most DNO's adopted earthing preference, you are going to see something addressing issues and short comings with the system, be it by way of amendment's or in a future 19th edition, who knows ? WE have RCDs we have RCBO's we have SPD's and soon we may have the edition of lost PEN monitoring devices on TNC-S systems, who knows. We all have our opinions after all, and its great to discuss different view points ??

 

[Simon47]

How can you Code the loss of a PEN connection when no mention of this is made in BS7671. I really don't get people's obsession with PEN losses.

Because a) it happens, and b) when it does, then the suppliers "earth" terminal is now "live" at anything up to 240V depending on loads on the system.
Within the house there isn't a massive problem as stuff is bonded to form an equipotential zone and so even if all your "earthed" metalwork is at (say) 150V, there's no touchable sources of true earth to cause a shock - like working in a Faraday cage.
Once you go outside then it's different - hence why the restrictions on charging EVs now.

EDIT: Removed the load of stuff that belonged in a different thread

 

[newfutile]

I think this why be why the proposed amendment 2 includes earthing house foundations , this will be another PME earth make a more complete faraday cage, until a cat or dog walk outside .