Main protective bonding

[tuckermot]

I believe the reading of 0.05 ohms is to do with the pipe work going live under fault conditions and bringing all extranias conductive parts to no more than 50 volts touch voltage !!

 

[pushrod]

The 0.05Ω figure comes from guidance note 3, but i am led to believe its use is set to become clearer in the present reviews of BS7671 etc that are about to be published. When me and Chr!s have asked questions of the IET about it they have been decidedly vague.

 

[Octopus]

Not looking for an arguement but how does 131.8 say that its ok to leave as is? As I read it it says you can't make additions or alterations unless the existing is adequate. I had a discussion with my assessor and he said that 6mm bonds were ok if they showed no signs of deterioration but the PME regs require 10mm. Where do you get the 0.05ohms figure from?

I got the advice from Elecsa (who reminded me where to find it in GN3)