What Size Cable Do I Need For My Garage

[oioi727]

Hi,

I wanted some independent advice, before getting a sparky involved. I am building a garage at the bottom of my garage approx 30 meters away from the house. I would like some advice on the thickness of the cable required?

Will 12mm be enough or should I got for 16mm or even bigger?

I plan on adding some basic lights and maybe power the odd drill or jig saw.

Thanks,

Shaz

 

[Iggifer]

12mm² doesn't exist. Sizes go 6mm², 10mm², 16mm² and 25mm² (and bigger)

It all depends on what you're actually likely to want to run at the same time (and room for expansion)

Your electrician will be in a better position to advise. It could be anywhere from 4mm² to 25mm². If it is just lights and the odd power tool 6mm² may suffice

 

[sparkwright]

As said 12 mm2 doesn't exist.

How are you determing these cable sizes? Don't forget cable is measured by the cross sectional area of each live conductor.

The measurements do not refer to the diameter of the whole cable, or anything like that.

Also, you will almost certainly require steel wire armoured cable (SWA).

 

[stillp]

Whatever size you decide on, use the next size up. The extra cost will be a small proportion of the overall cost, and you'll then have spare capacity if you ever need it.

 

[oioi727]

Thank you all for the quick reply.

My neighbor is having some work done in his garden and noticed the previous owners had run a cable to the garage, but instead of connecting to the consumer unit they plugged it directly into a plug socket.

He gave me some cable sizes, to be fair he wasn't so sure about the cable sizes he did mention that he has got a 16mm cable instead now.

I am curious about the correct size of cable to use and will speak to a qualified sparky before any thing is done.

He also got a 100m 16mm cable from a local scrap metal merchant for £50, which seems like a real bargin!

 

[winston1]

Hi,

I wanted some independent advice, before getting a sparky involved. I am building a garage at the bottom of my garage approx 30 meters away from the house. I would like some advice on the thickness of the cable required?

Will 12mm be enough or should I got for 16mm or even bigger?

I plan on adding some basic lights and maybe power the odd drill or jig saw.

Thanks,

Shaz

Well 1.5mm2 should be OK if that is all you require, but use 2.5mm2 to be safe.

 

[Taylortwocities]

Well 1.5mm2 should be OK if that is all you require, but use 2.5mm2 to be safe.

The distance you need to measure is from the supply to the garage. For a 30metre run even 2.5mm² would be pushing it.

If you are installing something like this, now is the time to future proof it, so just think about possible future use. What may you have in 5 years time? An electric heater, kettle, lathe, hot tub, home gymnasium??

You need to determine that and give the results to your electrician to design and specify the cable. You cannot do that on an Internet forum, or by getting some gash cable from a scrap merchant.

 

[endecotp]

He also got a 100m 16mm cable from a local scrap metal merchant for £50, which seems like a real bargin!

Did it have "property of british rail" printed along it?

 

[oioi727]

Thanks Taylortwocities, will definitively get the sparky involved, lol at Gash cable, that thought has definitively been running through my mind.

I have not had a look at the cable myself, don't really plan to either, I hope its not "property of british rail"!

Thank you everyone for your feedback, really appreciate it.

 

[rsgaz]

now is the time to future proof it

Agreed

That's why I personally would run two twinwall ducts into the trench you'll need to dig, then in future you can add/swap whatever cables you want with minimal hassle.

Gaz

 

[bernardgreen]

Did it have "property of british rail" printed along it?

Or maybe it was scrapped as being sub standard

http://electrical.theiet.org/wiring-matters/37/sub-standard-cables.cfm

 

[flameport]

He also got a 100m 16mm cable from a local scrap metal merchant for £50, which seems like a real bargin!

If that was copper cable, £50 is less than value of the scrap copper contained within, they clearly wanted rid of it. Meaning it was stolen.
Either that or it was made from copper plated steel or similar substandard stuff.

 

[ban-all-sheds]

But are you looking at the value if it were totally stripped out? Dunno what the delta is between clean copper and an armoured cable as is, but getting the copper out is not trivial, so if you have to consider the economics of paying someone to strip it, it may well be that the unstripped cable at £50 is the best you can do.

That said, if it came from a scrap merchant it probably was stolen.

 

[Iggifer]

I went a couple of months ago, and they were paying £2.85/kg for dry bright and 60p/kg for SWA (although I think 16mm² and 25mm² is a smidge higher).

I weighed in around 20m of 4c 25mm² SWA, stripped and around 100m of 16mm² singles stripped. That came to 53kg. Also a few 25mm² tails, but not many. Call it 15 metres.

100m of singles is 16.5kg unstripped and 25mm² 4c is 48.5kg. 15m of 25mm² tails is 4.71kg

Total Unstripped: 69.71kg x £0.60 = £41.83
Total Stripped: 53kg x £2.85 = £151

It's actually super easy to strip XPLE SWA down to the copper. It just leaves you with a lot of crap to get rid of after the deed is done.

 

[ban-all-sheds]

OK