Taking that the Ib is 60amps (k.m.f il install with bs1361 60amp fuse in it) distance of 80 metres will be 35mm swa having a volt drop of 6v. I believe this to be the correct size, correct me if im wrong
I see where your coming from but lets say you loose your pen conductor at the very source from the transformer. Not at the point at which you make it a tncs when connecting your earth. But the very source. If that pen conductor goes down, where is your mean of earth?
Section 705
705.411.4
Read that little paragraph mate, starts with tncs shall not be used.
I dont make the regs, it was a question i had of the nic eic on the onsite assessment
Ok lets say you exported the earth on a tncs to an outbuilding, and then lets say you lost your neutral at the main incoming, if you had a live to earth or neutral short, every thing connected to earth would become live under fault conditions, hence why you need to rod and not export form the...
Under the Electricity safety, quality and continuity regulations 2002 you cannot use a suppliers earth to an out building, on a TNC-S Earthing arrangement, so the detached garage effectively becomes a TT installation with an earth electrode installed in the ground.
So why is this done out there, having main switch on the board rated higher than the fise in the head, it dont make sense the fuse in the head would alway blow first.
Not allowed to export the earth. Think about it, if you loose your neutral on the main, youve also lost your earth, so anybout building ect will not be earthed
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