Thinking of wiring up a garage with existing equipment

[squidge]

I've built a garage recently, its now all waterproofed and I'm thinking of putting some electrics inside.

Just not sure exactly how I should run the electrics inside. I'm no qualified sparky and don't believe I know everything (far from it) but I consider myself competent on domestic installations (apart from stuff I've not seen before, but I only work on my own system so thats a moot point).

I've a spare 8 way CU that I thought about putting in the garage. Probably overkill but its free and in known good condition. I've always wired up sockets in a ring for the usual reasons, but I'm thinking now since I have so many spare circuits putting each of the 3 double sockets I intend to install in the gargage onto its own circuit and not bothering with a ring (since only one socket per circuit). I see no problems with this, anyone else?

Secondly, I wanted a dedicated double socket for outside tools such as lawn mowers and the like (but the socket itself located inside the garage). Normally I'd use a socket with built in RCD for this, but considering it has its own circuit and breaker in the (garage) CU, is this necessary? I've no problems putting one in if its going to be a little more sensitive when I slice the cable in half with a hedge trimmer, but I remember something about having too much RCD = bad, so I'd like to confirm this before proceeding with that part.

 

[Phil]

the installation will fall under the scope of part p so you will either need to inform building control before you start work and have them come out at various stages of the work or join a scheme for compliance with part p.

some bc`s charge upwards of £150 just to register the notice.

as for the advice to the wiring a bit more is needed to be honest ie what supply have you got? how long will the cable be run and how.

btw welcome to the forum

 

[FAA Greenie]

Hi. Couple of points, I'm assuming that you are taking a feed from the house CU, is this RCD protected?

If it is, you should a seperate circuit for the garage, from an RCD protected MCB with at least 4 or 6 mm cable if you think you might have heavy use. If not, any socket outlets that will be used for outside equipment MUST be RCD protected. To be honest, I would protect all your sockets, though strictly speaking, if they are clipped direct to the garage wall, (ie not hidden in plaster/behind plasterboard, you don't have to). Personally I would just run a 2.5mm ring through all your outlets unless you have a specific reason not to. If you run them individually to each socket though, remember to use a 20A MCB, not a 32 as you would a ring.

 

[malcolmsanford]

Hi. Couple of points, I'm assuming that you are taking a feed from the house CU, is this RCD protected?

If it is, you should a seperate circuit for the garage, from an RCD protected MCB with at least 4 or 6 mm cable if you think you might have heavy use. If not, any socket outlets that will be used for outside equipment MUST be RCD protected. To be honest, I would protect all your sockets, though strictly speaking, if they are clipped direct to the garage wall, (ie not hidden in plaster/behind plasterboard, you don't have to). Personally I would just run a 2.5mm ring through all your outlets unless you have a specific reason not to. If you run them individually to each socket though, remember to use a 20A MCB, not a 32 as you would a ring.

I'm normally would never be critical of people trying to help as they give it free and are genuinely trying to be helpful but please do not take too much notice of this advice.

Taking your feed from the RCD side of your house CU is not the best of ideas. If you have a fault in your shed then it will take all the house circuits that are on that RCD. The best way to do it is come off a Non RCD circuit, if you have it, and by running the cable in SWA the cable itself will not RCD protection, unless you have a TT system.

You can not just advise on a cable size without knowing length of run, loading, and therefore saying a 4mm/6mm is what you need, is not what you need, it maybe 10mm or even 16mm who knows only the designer would.

All socket outlets in a domestic situation, that are under 20amps NEED to be protected by an RCD, regardless of the possibility for mobile equipment under 32amp being used outdoors.

IMO it is a poor desgn to install 3 double sockets in a A1 ring, for such a small area and in a garage, unless your going to be using heaters, heavy duty machinery etc, then a A3 2.5mm 20amp Radial is more than adequate.

For your questions there are far too many imponderables to give you sound advice. As Phil said first off this work comes under the dreaded Part P notification and by the time you pay the LABC for this, it would be as cheap to get an electrician who is a scheme member to do it.

Even if you do decide to do the work yourself which your entitled to do, you will need to test and certifiacte the installation, which involves several complicated tests requiring expensive, calibrated test equipment, which in fairness you can hire, but can you use it after you hire it? and then complete the relevant certification

 

[mattmoo1974]

To be honest mate does nt sound like a big job(Unless feed for your CCU in the garage is going to be a nightmare) I just pay a sparky for the day if he uses your CCU(Condition Willing)
At least you get the paper work for this if you ever sell. By know means am i touting for work for some one, But i think the benifits of using a sparky will far out weight the cost.

 

[Deleted member 26818]

Ring Final Circuit, one RCBO, all socket-outlets protected.
As malcolm says, all socket-outlets for general use by ordinary persons must be protected by 30mA RCD.

 

[Paul.M]

As above, your not changing a plug socket here your running a main feed + installing a new (2nd hand?) C/u + installing 3 new sockets + most likely lights. This is not a project to have a go at yourself. A number of things need to be taken into consideration before the first bit of materials is bought or the first run of cable is laid. Only if you have had training or know the regs + formulas to carry out this work you should leave it to the experts on this occasion.

Get a couple of quotes and ask if you can help him running the cables. You'll get a much better job done by a pro, safe, certificated, guaranteed and cheaper than doing it yourself + the costs of notifying the local building controll.

 

[Octopus]

If you mention where you are I'm sure that there will be a sparky or two on here who could pop round and give you an estimate, with LABC notification included.

 

[Electricalserv]

Why do people complain about non sparks doing their own work and then tell them how to do it.....Really annoys me this lads...

He needs to contact building control and they can see if he is competent himself. He surely can't be because he's asking how to design and install it.

 

[Paul.M]

Why do people complain about non sparks doing their own work and then tell them how to do it.....Really annoys me this lads...

Where do we draw the line on giving advice? On this occasion the job is to big for a diyer. Yes he will be able to run the cables, fit the sockets etc but will it be safe to energize and use?

May be the members should be given some guild lines for giving advise to none electricians from the admin? I'm not talking about is the forum or a member liable if the wrong advise is given and it causes injury. We could post on each thread that asks for our help "get an electrician in". This could be a debate for another thread.

 

[Octopus]

Why do people complain about non sparks doing their own work and then tell them how to do it.....Really annoys me this lads...

He needs to contact building control and they can see if he is competent himself. He surely can't be because he's asking how to design and install it.

How sure are you that the local LBAC will be able to make an assessment of competance of an individual?

 

[Electricalserv]

How sure are you that the local LBAC will be able to make an assessment of competance of an individual?

Well I'd b suprised if they sent out someone who didn't know the regs....After all they are looking at Part P.

I just think that useing the website as a one stop shop fro advise is again helping the non qualified in their quests to take our work away from us!!

 

[Electricalserv]

Where do we draw the line on giving advice? On this occasion the job is to big for a diyer. Yes he will be able to run the cables, fit the sockets etc but will it be safe to energize and use?

May be the members should be given some guild lines for giving advise to none electricians from the admin? I'm not talking about is the forum or a member liable if the wrong advise is given and it causes injury. We could post on each thread that asks for our help "get an electrician in". This could be a debate for another thread.

Paul it's exactly this.... I mean telling a spark from a non spark is very hard over the net....But when someone blatently comes on and says their not a spark I think no-one should be giving advise.

 

[Paul.M]

I've started a thread in the Arms (to keep it away from public view) about this subject. If anyone has opinion on this matter send it to me on a pm and I'll copy and paste it over. The thread will be put in the open forum later this week (if the mods will do so?).

 

[SMB]

I think that this place is all about advice.

Its a difficult one. Im fully qualified, (some how I got the 2391 !?)..however, I need advice on a regular basis (because im actually a village idiot).

Im glad I can come here and ask for advice, and advice has been freely given, and gratefully received. The advice I have received is in safe hands because even though I am a village idiot I have 'half a clue'.

I do understand where you are coming from Electricalserv in regard to advice 'dished out'. A little knowledge can be dangerous. But, what do you do?

From my experience this is a HELP forum. People advise here. People can not change the way others are going to behave. If someone has got it in their minds that they are going to rewire their house then they will do so.

Part P doesn't even come into the equation behind locked doors.

Advice is good. Thats why people log on to this forum.