Garage Wiring.....Electrician Advice required

Trust your sparks. Would go with 4mm as a min.

 

Having a workshop, think about 3 phase supply, best thing I did in my last workshop, picked up load of cheap 3 phase machinery.
My old arc welder runs either 415v,240v, using it now on 240v 16A radial & still occasionally throw the trip, so annoying.

 

You sound like you have a lot of machinery you plan on installing later,so If your planning on upgrading, do it once and get your sparks to run in some 10mm on say a small 5 way board with RCBO's ,I would put a type C in for the welders circuit and for 8 mts thats no wedge whatsoever.

It also guarantees a good supply and the next thing a water supply might go out there with a sink (washing hands after welding) so your ADS is up to scratch as well

 

Thats crazy asking for the DNO to run in TP+N for a domestic garage, £££££££

 

It cost me just under £300, about 5 years ago, well worth the expense in my case, I picked up a 400v large pillar drill for £20, to buy similar in 220v would several hundred pounds or more, still used ocassionally, motor now changed to 220v.

 

I would expect for a "normal" garage it's fine, perhaps a couple of extra sockets would not have been unreasonable.
For what you are looking at, now and in future. I would say it may be a little more than a normal garage load for the majority.

 

It comes down to the current carrying capacity of the cable. 1.5mm is not suitable for sockets although technically if you did calcs and installed a suitable mcb nothing is stopping you from doing it. You would be limited though as a 6amp supply won't give you much to play with.
As a minimum a 2.5mm which will give you 16amps but 4mm would be better. It all comes down to what is going to be running in there. If it's occasional use of a drill and a couple of battery chargers 2.5 will be fine.
I

 

1.5mm SWA would be fine on a 16A breaker, possibly even 20A VD permitting.

 

Lights should be a radial not a ring.

As previously stated, 1.5mm is inadequate. Go with what your electrician says and tell him about your projected plans so he can size accodingly.

Kind regards

 

Are you sure it's a ring, or just a point on a radial?

 

Wernert, don't worry about having 'ringed' your lighting circuit. If you are confident you have done the work to the required standard, then it's fine.

A 1.5mmT&E supply cable is, tho', nuts. And the builder must be well chuffed with the £ew squid he saved with this astonishing cost-cutting exercise...

Yes it's fine for one 13A socket and a single, solitary bulb, but not for much more. He's a cheapskate.

If you see him, thump his once, solidly in the face.

And then kick him in t'nuts.

I doubt he was generous enough to lay the cable in a duct so's you can easily pull through a larger size? No, I didn't think so.

Kick him twice in the nuts.

You will need a much larger supply cable - you know that now, don't you?

So, the builder did nothing technically 'wrong' by using only 1.5mm cable 'cos he only fitted one socket, but what a complete git.

As said above, talk through with yer sparkie all your future plans, and he will give the best recommendation. If he says "I'd go for 6mm (or even10mm) to comfortably cover all future eventualities..." then nod and say "Cool."

Because you don't want to be changing that supply cable again.

 

I fear he can legitimately say 1.5mm is enough for a double socket plus light.

But what a cheapskate...

Yes, you'd want to run the new cable to its own MCB in the house's CU. And RCD it too, but I don't know where - probably in the garage's own CU.

Your sparky will sort all that for you.

 

A detached double garage is sold by a builder as just that. If the buyer wanted it wired as a workshop then the thicker cable , garage CU and multiple lights and sockets would be an extra to the normal specification at extra cost.

 

Fair point, Paul.

Usually you have the option to upgrade whilst the house is being built - don't know if this applied to Wern.

For an attached garage, I wouldn't expect more than the usual 2.5mm. But for a detached double garage around 8 metres away from t'house, using 1.5mm2 still deserves a thump and a kick in my books.

It's makes even my canny Skots meanness cringe.

(Not that I wish to promote violence in any way - my thumps and kicks are all metaphorical...)

 

1.5 on a sub main is tight and mean to say the least, might as well say heres a single socket and a jar of glow worms cause thats the most your gonna get out of that supply

10mm do it once, do not scrimp on the run of 8 mts, EVERY eventuality is then covered