Special Location or Not??

new_spark · Mar 26, 2012

Morning,

I've got a job on what was once a dairy farm, it hasn't been used as such for many years, it has a 3ph supply to the house from which the single pahse db in the house is fed with a 3ph supply going out to the old barns and milking parlour.
It appears that the earthing arrangement for the whole installation is a TNCS, I can't find any trace of a TT installation for the out buildings.

I have rewired the house, no problems but now the owner wants the installation in the out buildings upgrading, it has an old board with BS 3036 fuses which supplys mostly lighting and some sockets, the owner wants it all re-wiring new lighting and some additional sockets for general use and light commercial use(one building will be a wood shop for his own use) the question is should it be classed as a special location still or can I treat it as you would for normal outbuildings and what are your thoughts on RCD protection?

TIA

malcolmsanford · Mar 26, 2012

You can only treat the new installation at face value and your design criteria is for a small commercial outlet and therefore that is what you design for. So a buildings former use is really irrelevant

That is one building you mention, are there any plans for the others.

As for RCD, personally I would not be going down that road for this type of installation. But to be honest I would like to see a scope of requirements before I commented too much on that

Engineer54 · Mar 26, 2012

I would say that as long as these building upgrades are not being used for livestock of any kind, it's not a ''Special Location'' and the PME supply is suitable for these buildings new useage, such as a personal wood working shop!!

If any of these outbuildings was going to be used again as a milking palour, then you would need to leave the PME behind and TT the milking parlour (or any of the outbuildings if being used for livestock)