Adding 5 double plug sockets to garage

Joshw1024 · Aug 18, 2021

Hi,

I am looking for some advice on the best way to install 5 double plug sockets into my garage, all of which will be running multiple computers.

My CU is located in the garage.

Would it be best to install the sockets onto their own ring main, or to add them onto the existing garage circuit?

Any advice is appreciated.

Thanks,
Josh.

EDIT: I am only installing the sockets, I will consult an electrician to connect them to the CU if required.

buzzlightyear · Aug 18, 2021

before we can give you the answer, what kind of consumer unit is installed and if so how is the wiring going to be installed.

James · Aug 18, 2021

How many computers? You say 5 twin sockets, each with multiple computers.
the sockets will need to be protected by an rcd and this could be a problem if you are running more than 10 computers.

I think you should get an electrician to come and specify this because of the possibility of large earth leakage currents.
if your house has a single rcd that protects it, you may well be in darkness regularly.

Joshw1024 · Aug 18, 2021

buzzlightyear said:
before we can give you the answer, what kind of consumer unit is installed and if so how is the wiring going to be installed.

i'm not sure exactly what CU is installed, see attached image.
The sockets will be on the opposite side of the garage from the CU, so was hoping i'd be able to run 2.5 cable in conduit across the garage ceiling to the CU, and wired into one of the empty slots.

Joshw1024 · Aug 18, 2021

James said:
How many computers? You say 5 twin sockets, each with multiple computers.
the sockets will need to be protected by an rcd and this could be a problem if you are running more than 10 computers.

I think you should get an electrician to come and specify this because of the possibility of large earth leakage currents.
if your house has a single rcd that protects it, you may well be in darkness regularly.

Currently there are 6 computers, on sockets wired into the upstairs circuit ring main and I have no problems.
I'm moving them into the garage for various reasons.

See image in my previous reply for the CU.

catdog1121 · Aug 18, 2021

Joshw1024 said:
Currently there are 6 computers, on sockets wired into the upstairs circuit ring main and I have no problems.
I'm moving them into the garage for various reasons.

See image in my previous reply for the CU.

There are lots of variables here, what size cable is feeding your garage? What type of cable is the feed to the garage? What size is the circuit breaker? Is there any RCD protection, if so where is that protection?

There are also computers then there are computers, do you know what sort of current draw they have?

A lot of garages are fed by a small supply cable as most people just want to plug in say a lawn mower and have lights in the garage, you may need to increase the size of the supply cable.

Having just 6 computers you should be ok on the earth leakage just about but if you ever want to add more it might be worth thinking about a separate circuit for future expansion. If you do need to increase the supply cable think about also if you would ever want to put a car charger on the garage wall. What about any possible heaters in the garage?

I know it just seems like you add some more sockets but it really depends on the load requirement and what is currently in place, nobody on a forum can really tell you that so you need an electrician.

richy3333 · Aug 18, 2021

You're not mining crypto currency are you?!

buzzlightyear · Aug 18, 2021

richy3333 said:
You're not mining crypto currency are you

do you need a pick & shovel for them.lol.

pc1966 · Aug 18, 2021

If you can, I would suggesting running some SWA cable from your house CU to the garage CU and feeding it off a non-RCD MCB at the house. That allows you the option to have 2 or more radial circuits in the garage, each on separate 20A RCBOs if you do encounter problems of high leakage tripping things.

On a hard fault you won't get selectivity, as the "instant" trip of the supply MCB will easily be reached by such a fault before the down-stream MCB/RCBO has any chance to clear it, but that might be an acceptable situation for you. If not it means a slightly more expensive job to have a fused-switch feed the SWA from the supply before the house CU (i.e. independant of the house CU).

Newer computers are not too bad, typically they are only 0.5-1mA or so and 6 double sockets will be passable off one 30mA RCD (recommendation is you design for no more than 10mA leakage on any circuit normally), but start adding UPS and extension blocks for odd extras and the future is murky...

Where you might see it trip is if there are any voltage disturbances so you get a high dV/dt on the supply and all that capacitance pushes things over the edge.

pc1966 · Aug 18, 2021

Also to add, you might want to consider lights in the garage with battery back up in case power does go off and you are plunged in to darkness. You can get LED batton lights with that built in for only £40 or so extra.

Strima · Aug 18, 2021

Some might want to reread the original post, the CU is located in the garage.

ruston · Aug 18, 2021

pc1966 said:
Also to add, you might want to consider lights in the garage with battery back up in case power does go off and you are plunged in to darkness. You can get LED batton lights with that built in for only £40 or so extra.

I used to put non maintained EM lights in garages and workshops that had , or likely to use rotary machines or the like.

pc1966 · Aug 18, 2021

Strima said:
Some might want to reread the original post, the CU is located in the garage.

Doh!

In that case are there RCBO available for that CU? If so then putting one or two in the free "non RCD" slots would be my way forward.

telectrix · Aug 18, 2021

and if it's a new circuit it's covered by the BC Gestapo, not that they could tell a new circuit from a new lettuce.

Joshw1024 · Aug 19, 2021

Strima said:
Some might want to reread the original post, the CU is located in the garage.

Just to clarify, the garage is attached to the house and the CU is located in the garage.

My apologies if it was worded badly. I will edit the original post to make it more clear