External sub mains which type of earth do you use as the CPC…

[electro]

When the origin is a TNCS and you are running to say a shed/barn which you are going to make TT. Which do you use to protect the sub main run the TNCS or the TT?. I’m thinking it’s the TT earth you use to protect the incoming cable. What do you guys use?

 

[IQ Electrical]

If the protective conductor forms part of a cable (as in SWA) the protective conductor should be earthed only in the installation containing the protective device.

It should then be insulated from the TT system.

 

[electro]

Yea that make sense, It’s just the hang up of taking the TNCS out of the equipotential zone especially 200m +
Thanks IQ