Electrician - Power to Garage, Advice Please

muckybutt

Putting power to the garage is also notifiable to the council to comply with building regs as it is classed as a special location.
Personally I would ask a sparky to do the work and fit the RCD to the main incoming supply, then feed the garage supply via a new MCB, doing that you will then have full RCD protection on all circuits.

Jonesya

zax47 wrote: »

17th Edition requires all circuits for special locations (kitchens, bathrooms, outside) to be RCD protected regardless of the RCD requiring provisions (buried 50mm in fabric of building, etc.etc.etc.) affecting circuits for other locations. So yes, it should be RCD protected at source.

RCD in the garage is protecting the garage circuits, not the supply cable!

I'm doing my 2382-10 in a months time so this has caught my interest.

Under the 17th edition regs. kitchens and 'outside' generally are not listed as special locations albeit certain outdoor installations are - basins/agricultural/marinas etc. Granted, what ever is installed at the garage would need RCD protection for the sockets, any buried cabling etc. But which reg would require the cable (presumably a distribution circuit?), if armoured, from the house to the garage to be RCD protected?

(I'm assuming it isn't a TT system and the earth fault loop impedance is low enough to ensure disconnection by the MCB within the required time)

zax47

You really want us to hunt through the big red book at tea-time on a Saturday? You're the one just doing his 2382, you should be telling us!!

There's lots of debate and argument about the interpretation of a few regs which seem to contradict each other on this subject. It can be argued that if you use SWA then no RCD is needed at supply only at shed/garage but other regs then contradict this. If there is a MCB equipped CU then I'd always put it on a separate circuit, with an RCBO if no RCD.

You need to also consider whether exporting the earth is allowed to outbuildings - especially when the supply is PME! Look at 542.1.8 and 411.3.1.1 (I think, from memory) for more about exporting earths to outbuildings.