Author Topic: Running electricity to an external garage?  (Read 22384 times)

Running electricity to an external garage?
on: June 23, 2014, 16:43:55 PM
Hi All,

Seem to recall there being some practical minded folk on here.

I'm about to complete on my first house purchase and I'm going through all the improvements I want to make. I've just found out the external garage (which I had earmarked as a workshop / mancave) doesnt have any electricity wired to it.

Any idea how much it would cost to get an electrician in to do a job like that? Or alternatively, is it something I could do myself?

Its about a 6m run across a lawned garden from the house to the garage. I'll need lights and enough power for power tools / computers etc.

Cheers!
Formerly sexytw

Re: Running electricity to an external garage?
Reply #1 on: June 23, 2014, 17:05:17 PM
laying the cable and doing the garage end is easy

where's your fuse box in the house, and how easy will it be to get the cable there ?

you're probably best off doing most if it yourself, but then having an electrition come connect it up

you'll want to run the cable form the fuse box in your house, underground to the garage, then put a new fuse box i the garage and run the lights/sockets from there

where's the house ?  there might be someone local who can help you out ?

get yourself on ebay for some cable to run from house to garage
http://www.ebay.co.uk/sch/i.html?_trksid=p4684.m570.l1313.TR11.TRC1.A0.H0.X6mm+swa&_nkw=6mm+swa&_sacat=0&_from=R40
(6mm will give you loads of head room, but if you find bigger for cheaper (ebay lol) then go for it)

any idea how many lights/sockets you want in there ?

Re: Running electricity to an external garage?
Reply #2 on: June 23, 2014, 20:15:04 PM
Sounds good! Thanks for the pointers.

Im not in the house yet, should be 6 weeks or so, in SE London, Welling / Bexleyheath.

I'm pretty sure the fuse box is under the stairs so I'll need to get a cable through the kitchen and out of the back wall.

Diagram of back of house:


Garden to cross, garage is behind the ivy at the far end. There's also a short 6ft concrete gap that I'll need to cross, any idea on the guidelines for that?


I assume I'll lay that SWA in conduit under the lawn. I'll run some Cat 6 in a seperate conduit while I'm at it.

In the garage I'll want a few lights and a few double sockets dotted around.

I like the idea of doing the 90% and getting a sparky in to do the final 10.
Last Edit: June 23, 2014, 20:18:54 PM by addictweb #187;
Formerly sexytw

Re: Running electricity to an external garage?
Reply #3 on: June 23, 2014, 21:26:56 PM
may want to consider running a cold water supply as well.

I would get a sparky in first, explain what you want done & your prepared to do the donkey work to save money. At least he can give you a proper quote, a list on what to get & to check your fuse box to make sure its up to code & has the capacity for a new circuit.


I also just checked building regs for you  :-


Running the SWA cable below ground is the preferred option as this will hide an otherwise ugly cable snaking its way along your garden boundary to your garden building. There are additional considerations when sinking it though: the cable will need to be buried to a depth of at least 1 metre to comply with building regulations.  You should also lay warning tape under the earth along the run of the cable but at a higher level (about 6" or 15cm below the surface). The reason for these measures is to reduce the risk of the more energetic gardeners amongst us inadvertently trying to dig up or cut the cable!
[/size]If you do decide to lay the cable above ground (or along your fence), you are quite within your rights to do so providing it is a) SWA cable, b) the installation has been certified to part P building regulations and c) it’s on your side of the legal boundary. However, it’s worthwhile discussing your plans first with your neighbours - it might be that the additional effort/cost of burying the cable is worth it just to keep on friendly terms…
Last Edit: June 23, 2014, 21:31:41 PM by Eggtastico #187;

Re: Running electricity to an external garage?
Reply #4 on: June 23, 2014, 21:35:46 PM
you can burry swa directly into the ground with no conduit... but you might as well get some conduit (ebay) and protect it a bit... it has to be 2 foot under ground to be legit (and to keep your sparky happy) (replied at same time as egg, I thought it was 2foot but he says 1meter... you're best off googling that)

depending which way your floor joists go (opposite direction to the floor boards) it might be easier to go out through the dining room and around the outside... depends what your kitchen floor is like vs your dining room floor

to cross the concrete, you can either cut two lines through it about a foot apart with a still saw, break that bit out and then dig down... or if you're happy to do a bit more digging... dig down at each side and then go under it.... 6foot is a decent gap to cross but it's not too bad if you have decent access at each side... all depends on the concrete, and if it'll look odd where you've cut through it and patched it back in

get yourself a fuse box on ebay (make sure it takes mcbs... one fuses with switches you flock back on when they go off)
sockets are pretty cheap new, so might as well get them new unless you find a bargin
same goes for lights, new is best tbh
you'll probably need at least  1 100m reel of 2.5 twin and earth cable for the lights/sockets in the garage too.. check ebay but it's not normally very cheap on there
(fusebox and cable will be expensive new (probably £80 and £200 new, or £20 and £20 on ebay!)

checked again, and if you use 4mm cable you're good for up to 40amps at 20meters of cable... guessing this will be loads more than you need... and I've got a big coil of 4mm cable... so if you let me know how much you need when you're ready I'll send you what you need :-)

once you've got your cable in, you could mount all your sockets/lights, then run all the cables to them and either leave it to the sparky to wire them up, or you can wire everything up but the connection in the house to the fuse box, and get the sparky to check everything over before he connects it up

personally... I'd just wire it all in myself... but if you're not 100% happy doing that it's probably best to get someone in to do it

it's a pity you're so far away or I'd give you a hand :-)

Re: Running electricity to an external garage?
Reply #5 on: June 23, 2014, 22:24:26 PM
Jesus, 1m! Thats one hell of a hole! I was thinking 60cm would be challenging enough.

The concrete buts up to the house so I dont think I can get under it, I might have to go over the concrete close to the border before going under the lawn.

I'll take a look whats under the carpet once I'm in, I dont think there's any wooden floors so there's a fair chance I cant get under the floors inside either. Fingers crossed.

Thanks for the ebay pointers, I'll try and confirm with a spark as Egg suggested before I start then do it all myself.

When I finally get round to it I'll post my progress.
Formerly sexytw

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Re: Running electricity to an external garage?
Reply #6 on: June 24, 2014, 16:56:35 PM
I wouldn't bother. It looks like you will be spending 24/7 just cutting/trimming hedges.  ;D

Dave.

Re: Running electricity to an external garage?
Reply #7 on: June 24, 2014, 17:04:51 PM
I wouldn't bother. It looks like you will be spending 24/7 just cutting/trimming hedges.  ;D

Dave.

Plan to rip those straight out and put up nice big fences in their place. Should make the garden much bigger.
Formerly sexytw

Re: Running electricity to an external garage?
Reply #8 on: June 24, 2014, 20:38:36 PM
Id be tempted to run cable around the perimeter than dig 1m down. Can easiily hide it under/the otherside of the fence posts/panels.
Id also considered some plug socket in the garden for when you want BBQ's, etc. or plug in a Jet wash, etc.

Re: Running electricity to an external garage?
Reply #9 on: June 24, 2014, 22:12:43 PM
18" is the reg for swa cable depth in a domestic garden.

if depends how far you want to go. you need to make sure your consumer unit has an rcd to protect against electric shock before running cables outside. also if your earth system is TNCS, an earth rod might need installing to send power to an outbuilding.

As your consumer unit is in the middle of the house it makes it abit more of an issue wiring a dedicated circuit. you would use 4 or 6mm2 3 core SWA cable for that, it would give you 32/40A to your shed which is plenty to run all the lights, sockets heaters you would need.

easiest way is to spur off the nearest socket in the house which would be either in the family room or kitchen looking at your plan, with 2.5mm 3core swa that would limit you to 13A though, which would run lights, a couple of sockets and a <2000w heater.

I would definitely recommend getting an electrician around to have a look and give you a quote, he'll talk you through what he would do and even if you dont use him you will have learnt a bit about how to do it yourself.

I'm a spark and a very rough price if you dug the trench I would quote approx for :
wiring the dedicated circuit back to c.u.
laying and terminating swa cable in trench dug by others
fitting 3way c.u in garage
wiring 3x lights
wiring 6 x double sockets

approx £400

be advised additional work may be required on the existing house installation if your gas and water mains are not earthed (+£150)
consumer unit is out of date and need renewing (+£200)
an earth rod needs installing due to TNCS earth system (+£80)

the easier option I talked about would be about £300 (so £100 cheaper)

if you are near me i'd be happy to come give you some advice if you did want to do it yourself.

Re: Running electricity to an external garage?
Reply #10 on: June 25, 2014, 09:15:53 AM
you also need to contact building regs at your local council so they can check it all & make sure you got the certificates, etc.

Sometimes its worth asking yourself do you really need power there or if there are any other solutions.

Re: Running electricity to an external garage?
Reply #11 on: June 25, 2014, 21:57:58 PM
Extremely helpful Deviance, thanks. I'll have to have a good think, I'll definitely get a quote or two before I decide on DIY vs Spark.

The place is in SE London.

Power in the garage is a must, its going to be half workshop half drinking/poker/games den for me.
Formerly sexytw

Re: Running electricity to an external garage?
Reply #12 on: June 25, 2014, 23:07:05 PM
My prices are probably way off london prices, i'm in the northwest/north wales.

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