Rcd

lamb.a · Feb 4, 2009

We are suppling an outside portacabin with a steel wired armoured 3 core cable live neutral earth from a TN-S system. Does the portocabin reguire an earth electrode and does the origin of the supply have to have an rcd/rcbo fitted with a rcd and also fitted on the consumer unit inside the portocabin.

biggav22 · Feb 4, 2009

depends. are there any sevices with need main bounding in the portacabin? i.e incoming water or gas?
try the link below it is based on a domistic job but will be same idea. it was also written to the 16th but most still stands.

http://media.iee.org/Publish/WireRe...matters_electrical_installations_outdoors.pdf

lamb.a · Feb 6, 2009

There will be a water supply to the portocabin

Guest123 · Feb 7, 2009

Hey.

We do a lot of portacabins for local schools and the way I do it for TN-S is 25mm3c swa protected by 100mA RCD and 60A switchfuse at the origin then terminated into whatever board is in the cabin. Usually the board in the cabin has a 30mA rcd up front as main switch, I then bond everything back to my DB in the cabin i.e water, gas, steelwork etc, as the 25mm CPC in the swa is sufficient to carry any fault current back to the main intake un the school and de-energise the supply.

For TN-C-S, I do turn them into TT installations i.e 25mm2c and drop a 25mm earth down to my rod, the rest is the same.

Hope this helps.