DIY - Garage lighting

ikodel · Feb 15, 2014

Hi everyone. Found you guys through Google and can see this a good site. So I'm hoping some of you can answer some questions for me regarding the subject.

So our garage has no power provision but I want to install some LED lighting so I can work on our motorcycles without being troubled by the current deluge of rain hitting the UK.

I'm not an electrician but I've wired a few circuits in the house and replaced fittings, sockets etc. Nothing major.

An electrician told me roughly what would be involved to carry out this work, but I still have some questions.

Would I need to get the work certified upon completion if I were to do it myself?

There is a standard breaker box in the porch area by the front door.

The plan was to feed off that with standard electrical cable, through the house to the back door where I would install a secondary breaker.

Off this secondary breaker I would run 50 metres of SWA 3 core cable that will run outside and buried under the gravel drive to the garage.

That cable would meet a fused connector block in the garage, and then wiring to a light junction box to which GU10 light bulb cup holders would be connected.

I want to install 8 spot lights of LED type that are 8 watts per bulb and I estimate about 1.6 Amps each so 12.8 Amps total.

The current rating of the cable is 23 Amps so I'm good there.

Do I need another breaker inside the garage or is fused block and the breaker by the garden door sufficient?

Obviously I want to stay within regulation, but remain as low cost as possible.

Any information on this would be welcome.

Cheers.

The bits I intend to buy
Indoors 3 core cable - This
Breaker box - This
Outdoors 3 core SWA cable - This
Fused Terminal Blocks - These
Light fittings - These
Lights - These

Resu · Feb 15, 2014

Where to start mate. You wouldn't need a secondary breaker inside the house, just some form of connection between the twin and earth (not flex as you linked to), to SWA. I would consider running a slightly larger cable to make the job more worthwhile (ie. you could stick a couple sockets in there too). Your demand estimation is way off. You would also need to consider voltage drop at that distance. I'd also be sticking a small fuseboard inside your garage (similar to your linked "breaker box"). Plus your light fittings aren't fittings, only a part of a fitting (and not really the type you would want for "working light" output.

I'd suggest getting a quote from a local electrician, post up your location and someone is bound to be near you. They might let you do some of the "donkey work" yourself to save cost.

Engineer54 · Feb 16, 2014

You first need to know what earthing system you have at the house (TN-S / TNC-S / TT) as different requirements would be needed for each system. In fact there are far more considerations that need to be taken into account design wise, and your design as far as i can see, doesn't meet those of BS7671

Buried SWA cable needs to be at an absolute minimum of 450mm (ducted) to 500mm (direct buried) depth (depth of 2 X spade). It is also unlikely that you will have the necessary skills to terminate the SWA cable into the required glands without damaging the cable. ....And 1.5mm 3 core SWA cable, is a crazily small size to use over a 50m run.

To be honest This is ''NOT'' a DIY project, so get this job done by a competent scheme registered electrician who will also be able to certify/notify the installation . As Resu suggests, ask for quotes that reflects you doing the real donkey work, such as the trenching/backfilling and helping with the cable laying etc. You will save at least £250 in LABC notification charges alone, and be confident that the installation is correctly and importantly, ...is ''Safe''. It's a No Brainer as far as i can see!!

gnuuser · Feb 16, 2014

the lads are correct this isn't a job for diy.
first consult with a spark in your area and go over your plans with him.
some of the work might be able to be done by you and may save you a bit.
but again this decision is best made by the spark.
its a matter of safety and legality so its in your benefit to have it done properly

Pete999 · Feb 16, 2014

I agree with the others mate, this sort of installation is far too much for a DIYer you have admitted you are not an electrician, get one in to give you a quote and more importantly peace of mind, don't know if you have family or friends in the house or garage, but doing it your way would put them a t risk, please get someone in who knows what they are doing.