rcd protecting swa on tt?

[jstephens251]

HI guys,

Just doing a swa outbuilding supply for an Elecsa assesment

I was hoping for a 32a mcb to supply 6mm 3c to outbuilding but because of high zs will need rcbo on swa? I will then fit dp main switch at other end. Ideally wanted rcd at other end

cheers

 

[malcolmsanford]

As it is a 3 core could you not combine the seperate core and the SWA to get the Zs down. ?

 

[robsparx]

Yes the SWA would need to be RCD protected. I did a similar thing recently and there's a thread i started on here somewhere. Basically if its not practical to go to the supply whenever you need to reset the RCD, then put a tie delayed 100ma RCD protecting the SWA, and put your 30ma RCD in the outbuilding

Time delay RCD's aren't cheap mind. Think I payed about £70

 

[malcolmsanford]

Yes the SWA would need to be RCD protected. I did a similar thing recently and there's a thread i started on here somewhere. Basically if its not practical to go to the supply whenever you need to reset the RCD, then put a tie delayed 100ma RCD protecting the SWA, and put your 30ma RCD in the outbuilding

Time delay RCD's aren't cheap mind. Think I payed about £70

You would not take regulation 411.5.2 into consideration then, which is why the OP was asking about lowering the Zs, if it;s not possible then yes he will need to RCD protect the circuit.

 

[Engineer54]

If the installation is all TT, you might want to try adding another rod to the system. Anyone bothered to check with the DNO to see if the supply has been PME'd in that area?? If it has, then a lot of problems could be solved!! ...lol!!

 

[jstephens251]

thanks for replys guys will give it some thought