metal shed

garlicbread · Posted: Sun Jul 05, 2009 10:58 am Post Subject: metal shed

house is on a tn-s system, what is the best way to go, regarding earthing arrangmetns for the shed, can the shed be earthed through the armoured cable supplying power to the shed via the consumer unit in the house or does it have to be locally earthed using a rod.
shed is 10m from house

RF Lighting · Posted: Sun Jul 05, 2009 12:30 pm Post Subject:

Is the shed an extraneous conductive part?

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ColJack · Posted: Sun Jul 05, 2009 2:40 pm Post Subject:

given the title of "metal shed" then I recon it is..

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garlicbread · Posted: Sun Jul 05, 2009 2:58 pm Post Subject:

so should it have a separate 10mm2 earth to the shed, would having the shed on a TT system cause problems?

ericmark · Posted: Sun Jul 05, 2009 3:07 pm Post Subject:

I would say it's position in relationship to houses would decide the best option. Where a group of houses have gardens totally surrounded by them then a shed in that garden would be better earthed using the TN-C-S supply in order any item powered from shed or house have the same earth.

However where the shed is at the end of a garden backed onto with open fields then a TT supply may be more appropriate.

However this would be worked out by whoever was signing the "Installation Certificate" as the designer of the system who would be likely same person who would issue the LABC completion certificate and is not really a DIY job.

See here Electrical installations outdoors: a supply to a detached outbuilding for more info.