I am using 3 core SWA to take power to a garage. The SWA is buried underground between the house and garage and I am joining it to T+E inside the house as it is easier to manipulate.
I was planning on using the 3rd core in the SWA as the earth for the garage. Does the SWA armour need earthing in this case or is merely used as a physical protection for the cable.
Cheers
Martin
Martin Carroll coughed up some electrons that declared:
Hi Martin,
It does need earthing. Ignoring the regs for a minute, the best way to think about it is: what happens when I stick a fork tine through the cable.
Earthed armour will ensure the spike is earth before it hits the live, thus blowing the fuse/rcd/whatever safely.
Cheers
Tim
The SWA Armour should be earthed, even if you are using one of the cores for the CPC.
See:
On Sun, 31 May 2009 12:10:00 +0100 someone who may be Martin Carroll wrote this:-
Others have answered the question you asked. However, there is another more basic question, which is should you be exporting the house earth to the garage or providing a local one? The answer to this question depends on how far the garage is from the house and whether there are exposed metallic items like water pipes in the garage too.
The armour *must* be earthed. It almost defeats the point in having it otherwise.
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