Metal Fuseboard on TT

[somersetsparks]

On one of my 'other jobs' which I mentioned the other day,
One building which is TT and fed by an SWA, although the earths are isolated and this building is protected by a rod, has single insulated cores feeding the incomer (100ma rcd).
However the whole installation is protected by a 300ma Time delay at source, so would the double insulation of the incoming cores still be necessary?

cheers

 

[spark 68]

:29:No problem at all S1973,

I was sort of replying to everyone, but I put SS (Somerset Spark) as he was the OP asking the original question.

 

[sparks1973]

:29:No problem at all S1973,

I was sort of replying to everyone, but I put SS (Somerset Spark) as he was the OP asking the original question.

well i couldn`t quite understand...i thought the SS question was aimed at me.....but after looking at my other posts on this thread.....couldn`t work out why..lol...

 

[cheekygirl]

I don't do very much work on TT systems so wanted to clarify... Got a house re-wire coming up on a TT system. Checked with electricity supplier and no PME available so have to stay as TT. All circuits will need 30mA RCD protection as per 17th edition regs as they will all be buried in walls. Does the main switch still need to be a 100mA type S RCD under 17th edition regs ??

 

[somersetsparks]

Thanks for your help everyone, its put my mind at ease with the installation - which essentially is a decent one, especially for a farm.
I am going to replace the 100ma RCD like for like in the cowshed as at least it provides some discrimination with the main 300ma Type S upstream. The rest of the installation is ok as is now.
Using this forum is much more helpful then the NIC helpline!