Garage Wiring

In need of some advice, currently having a garage built at the side of my garden and obviously want it wired up. I haven't done much wiring myself, and have never planned a job like this. All connections & testing will be done by a qualified sparks but trying to save myself some money by running all the cables in advance.

In the garage I want 3-4 sockets, 1 light (possibly florescent?), Potential to put in a security light & electric door. The supply to the garage would be ran underground (SWA?) in total the run will be about 8-10 meters max.

Potential issues: The consumer unit is fitted under the stairs (plenty of space for another board if needed). The cable will have to be surface mounted (fitted just above skirting) until it gets outside due to concrete floor and work units, Also, where the cable will be going out of the house, I have Flow and Return (heating pipes) as well as gas that will be no more then 6 inches away (boiler sits above). Also have the condensing drain from the boiler straight next to where the cable will be coming out. If there weren't more problems, I also have the water main running down the side of the house which is buried roughly 12 inches deep.

So here's what I would like to know:

1. Cable type, size and dept that it'll need to be to feed what was described.

2. What type of consumer unit would be needed in the garage & what type of fuse would be needed in the existing board to allow for the new run.

3. Issues with cables being ran so close to central heating & gas pipes internally, water main & condensing drain outside.

Obviously I would have liked a proper sparks in to price up the job and tell me first hand how to do it, but the foundations have been laid and the brickies are coming on Monday and it's only just dawned on me I may actually need some power in there.

Any advice would be welcome and will provide more information if needed.

1.5mm twin & cpc

Welcome to the forum, unfortunately your question although very detailed for you, is not that detailed for an electrician to base any calculations on. We would need to know the length of run, the installation method used throughout the cable length and potential power consumption, as well as earthing arrangements and total demand as is. Electricians in your area would be all too happy to visit your home and give more information.

Why not get the job done properly by the sparks? the money you spend on hiring him may cause you less aggravation later on.

AndyGuinness

Hi there,

Can you not drill through the wall adjacent to the consumer unit and stick the cable through the wall and then run it outside??

john..

Welcome to the forum, unfortunately your question although very detailed for you, is not that detailed for an electrician to base any calculations on. We would need to know the length of run, the installation method used throughout the cable length and potential power consumption, as well as earthing arrangements and total demand as is. Electricians in your area would be all too happy to visit your home and give more information.

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Thank you for the response, The run will be about 8-10 meters from existing consumer unit to the new one, the ring circuit (in garage) will be ran in the ceiling, about 20 meters of cable will be needed, not sure on earthing, total demand (I assume what will be plugged in?), It'll just be general garden equipment, radio, charger for a motorbike battery. Only had the electrics done about 2 years and it was planned with the extension in mind (well I told him about the future plans). I was going to ask him to come back and get everything connected up and signed off as he done a very nice job of the house. I was hoping I could run the cable into the garage tomorrow before the brickies came on Monday.

Have to agree with Manator as there is more to providing a supply to an outbuilding than just second guessing what obstructions may or may not be present. Best to get a couple of local guys to quote/Advise

Hi there,Can you not drill through the wall adjacent to the consumer unit and stick the cable through the wall and then run it outside??

john..

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It's not an option unfortunately, the stairs are in the middle of the house, Kitchen one side, living room the other, If ran on the skirting, only about half a meter will be on show in the kitchen before it's hidden behind the work units.

id stick a 10 mm in just be safe :innocent . and also youll need to run armoured cable and run it in ducting underground in a trench 450mm deep cable duct should also be installed with sand over the top and electricity tape.

Thank you for the response, The run will be about 8-10 meters from existing consumer unit to the new one, the ring circuit (in garage) will be ran in the ceiling, about 20 meters of cable will be needed, not sure on earthing, total demand (I assume what will be plugged in?), It'll just be general garden equipment, radio, charger for a motorbike battery. Only had the electrics done about 2 years and it was planned with the extension in mind (well I told him about the future plans). I was going to ask him to come back and get everything connected up and signed off as he done a very nice job of the house. I was hoping I could run the cable into the garage tomorrow before the brickies came on Monday.

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I would initially ask the electrician that did your electrical installation for advice, failing that I would put the largest cable you could afford simply because it gives more options for the future. The earthing arrangements are vital, but your electrician can sort earthing out for you. It would be wise to put the cable in before any more work is done, the only factor is costs, an electrician could have done the calculations and used a suitably sized cable for your needs, now as your left at such short notice you can only install a cable that mey well be oversized and costing slightly more than you would have expected to pay.

I would initially ask the electrician that did your electrical installation for advice, failing that I would put the largest cable you could afford simply because it gives more options for the future. The earthing arrangements are vital, but your electrician can sort earthing out for you. It would be wise to put the cable in before any more work is done, the only factor is costs, an electrician could have done the calculations and used a suitably sized cable for your needs, now as your left at such short notice you can only install a cable that mey well be oversized and costing slightly more than you would have expected to pay.

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Thank you again, I think I'll do what you said and get the sparky back round, It'll be the best way to keep it cost effective and I can get the advice first hand. I'll just have to try and hide the cable with some plants. Not ideal but it's not a big issue.

I would also caution against drilling the hole through the wall where you suggest, in such close proximity to a gas main, water pipes and even the water main by the sounds of it. Drill through one of those and you have a big problem.

It's worth getting a sparks in now to look at the job. We deal with this sort of problem almost daily, and I'll bet he can find a route for the cable.

And more importantly, if you want to save money by doing some of the donkey work, discuss it with him right at the start. Once he's found the best cable route, and specified the cable you may agree between you what work you are doing and what work he is doing.

The alternative you are suggesting is to let the forum specify your cable, to install it, and then call a local sparky. That is likely to lead to guys not wanting to take on the job, or telling you you have done it wrong. Involve them right from the start, and you should get your objective of saving money by doing some of the hard work, while also getting the job done right, and in full agreement with your electrician.

The best you could do to assist is to put in the ducting from the edge of the garage to the point closest to the house, this way the spark who comes to do the install will have half a chance of getting a reasonable install without having to dig up your garden again.

Possible to route swa up under stairs through first floor & out through an external wall?

Possible to route swa up under stairs through first floor & out through an external wall?

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Only problem is that all the main connections for the upstairs heating circuit are located at that point, throw in the hot & cold, the badly cut joists that I wouldn't want to weaken them any further.

I'm going to let the sparks decide the best route. I'll leave it up to him and just do the labor for the day.

Thanks to everyone for their help/advice. much appreciated.

I'm going to let the sparks decide the best route. I'll leave it up to him and just do the labor for the day.

Thanks to everyone for their help/advice. much appreciated.

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probably best. not many sparks would want the hassle of digging a trench either, so unlikely to be an problem with you doing it, providing its to spec (depth etc)