Hi,
I have a C40A three phase circuit (final) with a measured Zs of 0.8 Ohms (0.55 max). Obviously this is too high as per table 41.3. The supply is a TN-C-S with a measured Ze of 0.71. Obviously the R1+R2 should be around 0.09, and low and behold was measured as such. There is a 300mA RCD in place adjacent to the 3 phase supply cutout (300mA due to sensitive equipment and requirement for no nuisance tripping as its a remote site)
There is additional protection afforded via a supplementary equipotential bonding conductor to the equipment.
My query is does this pass to issue a cert? I'm not the one signing anything of btw, just want to expand my knowledge.
Cheers Chaps
I have a C40A three phase circuit (final) with a measured Zs of 0.8 Ohms (0.55 max). Obviously this is too high as per table 41.3. The supply is a TN-C-S with a measured Ze of 0.71. Obviously the R1+R2 should be around 0.09, and low and behold was measured as such. There is a 300mA RCD in place adjacent to the 3 phase supply cutout (300mA due to sensitive equipment and requirement for no nuisance tripping as its a remote site)
There is additional protection afforded via a supplementary equipotential bonding conductor to the equipment.
My query is does this pass to issue a cert? I'm not the one signing anything of btw, just want to expand my knowledge.
Cheers Chaps