Outdoor socket from Garage

[infaddict]

Hi everyone, first post so be gentle

Firstly, I'm not an electrician and realise the work I require is covered by Part P and notifiable. I will therefore be getting a sparky in to do the actual work, but I like to research my requirements, understand the work and decide whether to buy the hardware myself if cheaper. So this is advice to help with that, not to complete the full job myself.

I have a 5 year old house with external garage. The garage came with power supplied, via a large SWA from the house, to a consumer unit on garage wall with 2 MCB's, one for lighting (single bulb) and one for sockets (1 double socket). I have photos of the house consumer board and garage consumer board attached for more info on fusing etc. In the house, the garage MCB is a B16 alongside a 80A RCD. In the garage itself, the lighting MCB is B6 ad socket MCB is B16, with a main switch (63A).

I want a double external socket fixed to outer wall of garage, conveniently the same wall as the garage consumer unit, only 2-3 metres away. There is a spare (blank plate) in the garage consumer unit which could be used. My question is around connecting a IP66 double socket (13A) to the outside of the garage wall, hopefully coming through the wall to inside the garage and up to the consumer unit.

My questions:

1) Is there enough capacity on the system (house and garage consumer units) to take an additional double socket?
2) What size MCB would be preferred in the garage consumer unit, to connect the double socket?
3) What size wiring would be preferred to run from garage MCB to outdoor socket?

House consumer unit picture: https://drive.google.com/file/d/1MjNVYs ... sp=sharing
Garage consumer unit picture: https://drive.google.com/file/d/1Fuf5bH ... sp=sharing

Thanks in advance!

[ericmark]

It is a lot easier if we can view pictures on the same site.There is nothing to stop you adding an outside socket.

However personally I would want an outside socket on a RCD which will not effect other circuits in the house, so I would move the garage supply to the non RCD protected side of house consumer unit and add a RCD to the garage consumer unit, so any water ingress will not effect other circuits in the house. But that is not required, just a good idea.

Why anyone fits a 16A MCB supplying a 16A and 6A MCB I don't know, seems pointless so the electrician may also change the MCB size once he has completed tests.

[Someone-Else]

so I would move the garage supply to the non RCD protected side of house consumer unit and add a RCD to the garage consumer unit,

Nice idea, one small problem.



House board has Two RCD's (so there is no NON RCD protected side of consumers unit.

[Someone-Else]

infaddict, ericmark is saying that if there is an "earth fault" in your garage (or anything you plug into your garage) then it will be the house that trips so you will lose the smoke alarm burglar alarm, some lights and some sockets. ericmark's way round it is to move the garage supply to the non-rcd side of your consumers unit...........but it hasn't got a non RCD protected side.

Also the sockets in the garage are protected by a 16A mcb, but the supply to the garage is also protected by a 16A mcb, its not ideal. I would mention all the above to the electrician who does your job.

It will no doubt be cheaper if you buy all the kit for the job, but here in lies the problem. If it fails you will blame the electrician as he fitted it, but its YOU who supplied it so its your fault, not his. Also if you buy some "cheap rubbish" and it fails you will want the electrician to fix / repair it FOC, but he won't as it was YOU who supplied it, best let him get all the right kit for the job.

[infaddict]

Thanks for all the helpful replies guys. Gives me some useful info to talk to the electrician about.

[ericmark]

Sorry missed the second RCD, there are ways around it, I did not work in domestic so the consumer unit type tested board was not used much by me, however some will take RBCO's and some there is not enough room, using RCBO's one RCD could be removed so you could have it so fault in garage does not trip house, but more expensive.

The get electrician to do all is good advice. I was in one job on the other end of this, the auto electrical place I worked in both sold to trade and general public, an alternator trade price at that time was around £18, the retail price around £25, we would fit customers alternators if they wished, so they could go to trade counter, buy an alternator for £18 then walk to garage section and pay £5 to have it fitted. Or they could simply say fit me a new alternator. So cost £23 or £30 for same job.

However if it went wrong, for £30 we would replace the alternator FOC, but for £23 we would charge £5 for replacing it, they were still getting it for less than the £30 however the amount of arguments over the £5 charge was unbelievable.

In your case worse, you buy stuff and it goes wrong, likely you did not get trade discount to start with, and you will need to pay for it to be replaced, and likely when you take it back the outlet will claim it was damaged by the electrician.

The electrician has more clout in the whole sale outlet, they want to sell him more stuff, so unless rather clear it was electricians fault, they will change it.

Offer to drill holes, dig trenches, and make good after he has finished to reduce costs, but not buying the gear.

I know my son was very wary of the customer helping after being caught out. He marked walls for chases and where holes should be drilled, and it was agreed all would be done by Thursday, however on Thursday it was not done, so either my son did it himself or he would loose a days work, so instead of 8 hours he was there 12 hours, but the guy did not want to pay extra, so son vowed never again. I think most electricians have been caught out like this, so many will allow you to make good, but not prepare for them.

[OnlyMe]

You can always supply the outside socket via a double pole switch inside the garage. If the switch is left off when you go on holiday etc then even if water gets into the socket the RCD will not trip and the contents of your freezer will be fine.

A 16A MCB feeding a 16A MCB is not important in this case.