Main Earth Conductor

[steptoe]

Sorry, I thought you were implying 6mm was fine on tns without calculation despite the case in this thread in which it had been calculated at 10mm.

no probs,

I dont express myself very well most of the time. :Blushing

but its not retrospective

you can put deviation on the cert,

its beyond your control,

its only a code 4 at best.

 

[Wattsy]

I've done the calculation again this time using t = 0.01 which is more realistic for an pefc of 3.2kA than the 0.1 which is the min BRB Ap 3 goes down to and got a result of 2.2mm2.

So it looks like the 6mm would be fineut the kettle on

Any comments?

 

[ianmacd]

I have seen too many tn-s systems by me Ze vary within a few hours so not sure I would be happy calculating the Earth Conductor but Main Bonds and circuit CPC's its a useful tool (esp when the helpful plumber tells customers that the 6mm bond to water thats almost impossible to get to without dismantling the building needs upgrading).