New roof going on today so my Garage will cease to be a leaky, Asbestos ridden hell hole, by the time I get home, next job will be getting a more permanent Leccy supply run out to it.

Her indoors wants a Chest freezer and possibly the tumble dryer to live out there, and I obviously want to use it as my workshop So I’ll want lighting, to run my compressor, a drill and probably some other power tools, probably chargers and possibly a heater in the depths of winter

I’m certainly no sparky so I need advising before I bollox it all up.

I think the Consumer Unit in the house has a spare unused RCD slot which I could use specifically for the Garage, But that might mean a fair bit more wiring through the kitchen and then out the back and across the garden (that’ll be a mission on it’s own)…

Alternatively it might be simpler to extend the downstairs ring out there from one of the existing Sockets or Junction boxes in the kitchen, with a switch inside to turn it all off should we want to, but would that be particularly wise given the amount of stuff we’re likely to be runing out there?

Advice please STW experts…

Advice please STW experts…

phone a sparky.

what jam-bo said.

Easiest might be to run an armoured 16A cable (which wouldn;t need burying) down and sort out a separate consumer unit once the power is in the garage.

I’m fairly sure you’ll need a seperate consumer unit in the garage, so it runs it’s own circuits. Our garage is connected to the house and has one, put it that way, with a circuit for the lights, another for the sockets and a third for the outside security light.

What they said. Sparky plus armoured cable plus separate consumer unit in the garage.

How about some insulation in the garage to help with the heating? Freezers tend to be designed for domestic temperatures as well.

Freezers tend to be designed for domestic temperatures as well.

we got a ‘garage friendly’ freezer but ours is attached to the house so doesn’t get quite as a cold as it could.

You could extend the ring into the garage. Provided you fused down the lighting, which is easy enough, you’d be fine. There are however design considerations with ring circuits and depending on the loads you’ve currently got it may not be ideal. The optimum solution is to run a separate feed out to the garage. When you say spare RCD slot, I assume you mean MCB slot? A photo of your consumer unit would be useful and I can advise.
Rich.

Have a read: http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=26184

I am doing mine at the moment.

I have run a 10mm2 SWA cable from the consumer in the house to a 2nd consumer on the garage.

From this I am going to have a socket ring, lighting ring and a separate ring for the welder & compressor. I am undecided as to whether I am going to add a fourth trip for a couple of outside sockets or add them into the socket ring.

Get a sparky to advise what you need, based on your intended use.

Sounds from your description it will be better to run it from the consumer in the house though as you could overload your current socket ring.

Also having a separate consumer in the garage allows you the ability to split and add circuit rigs as required. For example a his and hers socket ring so that if you trip the circuit breaker using your compressor and a drill and put the kettle and heater on you don’t trip the freezer and tumble drier.

Easiest might be to run an armoured 16A cable (which wouldn’t need burying) down and sort out a separate consumer unit once the power is in the garage.

Not having to Bury a cable would save a huge amount of bother TBH, and I think I can manage a nice out of the way route for it… are you really allowed to run armoured cables above ground?

Reading around the topic a bit more, the whole idea of taking a spur off the ring is not appealing it’s about as electrically safe as the extension cable I currently have for running lights out there, So that’s out…

I’m wondering if I could run a dedicated 30A line from the spare slot on the house CU out to the Garage using an armoured cable, and then put a second CU in the Garage so I can have separate circuits for lighting and sockets, effectively this gives me double isolation, right?
Could/Should I then put 16/13A protection on the Garage circuits to help protect the house?
does that make sense? or is it a bit OTT?

Would it be OK to create a “Mini Garage ring circuit” from the second CU?
I’m likely to want a fair few sockets in there if i can, just so the way I arrange the space isn’t dictated by the socket positions…

I reckon I could do a lot/most of the basic wiring and just have the final CU connections made/tested by the same sparky who put the household CU in for us originally…

Hmmm…

are you really allowed to run armoured cables above ground?

yes, or use a steel conduit and put normal cable inside it.

I’m wondering if I could run a dedicated 30A line from the spare slot on the house CU out to the Garage using an armoured cable, and then put a second CU in the Garage so I can have separate circuits for lighting and sockets, effectively this gives me double isolation, right?

This gets a bit more complicates as its not ideal to have RCDs in series unless they’re design to be (different cut out currents). The neatest solution is to add an extra mini fuse box on your distribution board with a 60A 100ma RCD, then run a cable from this to the Garage and then install a Garage consumer unit with standard 30ma RCDs. This way you have RCD protection on the armoured cable, but in the event of an earth leakage in the garage, only the garage consumer unit RCD should trip.

I’m in the middle of doing all this for my workshop (although rather slowly as it’s been > 18 months so far). I’ve run 10mm cable to the workshop in steel conduit and got as far as splitting the meter tails to add in a 100A Isolation Switch and extra meter tails for the Workshop RCD (but not fitted that yet).

As for testing, I’ve got all the regs / test kit and will test it all myself then get BC to sign it off.