Garage wiring?

GreySquirrel

Is it within regulations to run a "ring circuit" to a garage from the Consumer Unit just like an ordinary circuit

OR
are there different requirements?

RoundyMooney

You can run a ring circuit to a garage to feed your sockets, no problem at all.

I'd suggest using conduit, even plastic (easier to work) if you're going to surface mount your wiring.

Presumably you won't have too much of a lighting load, so that can be simply taken directly from the distribution board, or from an existing lighting circuit.

As always, ensure your socket circuit is protected by an RCD.

edit: Is the garage an annex of the property or a seperate building? If the latter, a small sub distribution board would be better.

GreySquirrel

RoundyMooney wrote:

...

Presumably you won't have too much of a lighting load, so that can be simply taken directly from the distribution board, or from an existing lighting circuit.

...


edit: Is the garage an annex of the property or a seperate building? If the latter, a small sub distribution board would be better.

I have some flourescent fittings that I'm thinking of using. Do they need a different lighting circuit?


Garage is a seperate building. How do I rig "a small sub distribution board"? Presumeably, that goes in the garage, but what about the house end?

RoundyMooney

Simple.

I'm assuming a conventional setup-tell me if otherwise...

Get thee some 6 square twin and earth cable, connect from the busbar in your distribution board that feeds into the bottom of your cooker and lighting circuits, (i.e. on the supply side of your RCD) Make sure the neutral connection to your new supply cable goes on the right busbar (there should be two-one before and one after the RCD-the one before-on the supply side-is the one you want). Many sparks will insist on SWA (Steel Wire Armour cable), but I consider this unneccessary once you encase the cable in conduit down the exterior wall, and in a suitable wavin pipe for the underground span. I also run a seperate 10 square earth for added safety. At the garage board, fit a switch fuse with a 35 amp fuse, feed through a 10 amp for your lighting, and through an RCD and 20 amp MCB for your sockets. A radial circuit is permitted rather than a ring, but I prefer a ring circuit personally. Don't put your lighting circuit through the RCD, as with flourescents, nuisance tripping of same can be a problem.

Work safely at all times, turn off your main switch fuse, and remove the fuse, and be very aware that the bottom terminal of your main incomer is at all times live.

If you're going to put an arc welder or the like in this shed, then you will need to take a different approach. This set up will not be sufficient.

GreySquirrel

Just back from Homebase for round head screws. I got some grommets in electrical aisle. Something made me buy ten metres of 6mm square!!!

Just home and read your post. Woo hoo!

Conduit already there. It's bad enough working with 10 mm squared. Will leave SWA for another day.

Do I take the feed straight from the busbar? That cable will have no protection?

RoundyMooney

No stick it through a 40A MCB and all should be well. Even if the main fuse on your sub board is a 40 as well, the MCB will probably drop out quicker.

Is 10 metres enough?

GreySquirrel

The garge is less than a metre from the house, so supply from CU to board in garage through conduit is less than ten metres. Can I use 2.5 mm squared for circuit in garage?

RoundyMooney

2.5 for sockets, 1.5 for lighting.

That said, I've used 2.5 in shed lighting circuits at least once, when badly stuck, but I wouldn't recommend it. Cost aside, the size of terminals in 5A switches etc., isn't exactly suited to 2.5 square copper...

GreySquirrel

Most of the stuff I have. I'll let you know How I get on

GreySquirrel

10 metres let me put mini distribution box near the back door of garage. Sockets up and running. have to get mcb for lights next.

RoundyMooney

Don't forget the RCD!

GreySquirrel

Yes, I have the RCD and MCB on socket circuits, MCB on lighting circuit.

Now I have no excuses not to tidy up and move stuff out to garage.