Electrical Sockets inside cabinets

[Jetset]

Hi all. I'm new to the forum but have been reading for several months. The info and links here are second to none.

I now have a question myself that I can't see an answer to:

I am making some alcove units soon and want to know if is it ok to mount the electrical sockets that would normally be in the wall, into the inside back or side walls of the cabinet?

I'm presuming it is, by using plastic drywall boxes -- the same backboxes that go into plasterboard walls. The trouble is, do the necessary cutouts weaken the cab? It will probably be made from 18mm MDF.

Any advice appreciated.

Incidentally, this is all part of a house refurb. If anyone's interested, I can post WIP pics. I know that I like viewing others.

Jim

 

[Jake]

No, you shouldn't do that. It is expressly deprecated in the wiring regs, I think. If not it is expressly deprecated in some guidance on the meaning of (one of) the regs. Either way, it is A Bad Thing.

The backboxes should be mounted on the building fabric, so you need to add appropriate spacers behind normal metal boxes and fix them to the wall.

 

[Jake]

Just re-read your post more carefully - it may depend on how your alcoves are constructed. If the MDF becomes the wall (building fabric) rather than part of fitted furniture (like a kitchen carcasse, which is the context in which the express deprecation is made if I recall properly) then it would be fine. There's obviously a grey line there.

I'd use metal boxes anyway, the end result is neater.

 

[NeilO]

Jetset, Welcome to the forum.
I woulld agree with Jake that if the stucture "becomes" the wall, it would be ok,
but if its a free standing unit theres always a danger of forgetting its electrically connected and if moved a chance of the live cable being pulled out of the socket :shock:

As for WIP piccies , do you need to ask :lol: only notch up a couple more posts before adding piccies, or you will be caught in the spamulator (memory serves me its 5)

 

[Jetset]

Thanks for the replies.

To make myself a little clearer, the cabinet would be built-in and permanently fixed to the wall, as opposed to free-standing. It would be a base cabinet plus shelf unit above which would also be built-in.

Therefore, sockets in the brick wall behind would be obscured and hence my need to have them inside the base cabinet. I suppose I could make the base unit without any sides or back -- and use the brick walls for that.

Jim

 

[Jake]

Fitted furniture, like kitchen cabinets are covered.

The proper way to do it (if you want sides and backs to the cabinet), as I tried inadequately to explain, is to cut out the holes for the sockets in the back of your cupboard, then mount the metal boxes to the wall behind so that they stick out the right amount to project through the cut out, just shy of the inside surface of the cupboard by a mm or two. Then the cabinet can be fixed into place, and the electrical socket fitting can go over the top of the box from the inside of the cabinet, covering the hole.

That's my understanding of the regs, anyway.

 

[Jetset]

Thanks for the excellent advice.

Fitted furniture, like kitchen cabinets are covered.

Do you mean covered by the regs?

Searching other posts, recommended reading seems to be the IEE On-Site Guide and elsewhere I've seen a book called The Electrician's Guide to the 16th Edition IEE Regulationsby John Whitfield recommended.

Jim

 

[andrewm]

I don't have the regs to hand but if the rear panel is close enough to the wall and permanent enough that putting the socket on the panel screwed into a metal box sunk into the wall behind is OK then would a surface mounted box be a better option?

Andrew

 

[Jetset]

Andrew

Thanks for the suggestion. I'll try to read up a bit before cutting in to anything!

Jim

 

[Jake]

I've found it. It is only guidance, not in the Regs, and, helpfully, it is in a bit which relates expressly to kitchens. It's in the IEE "Electrician's Guide to the Building Regulations" and states that wiring accessories
should be mounted on the building fabric and not on kitchen furniture.

As this isn't kitchen furniture, you can argue that it doesn't apply at all, and anyway the guidance isn't as authoritative as the IEE regs themselves, it is just a guide to good practice.

So I'll backtrack. You probably could use dry-lining boxes if you want. I still wouldn't.

Surface mount boxes are an alternative, but they are much more fragile than metal boxes, and they are sized so that the fitting is the same size as the back-box. With a metal box the fitting is bigger than the box so it overlaps and hides the backbox and any hole around it.

 

[Jake]

putting the socket on the panel screwed into a metal box sunk into the wall behind

I wasn't suggesting that the box be sunk into the wall - they can be mounted so that they are spaced off the wall by however much is needed with some plywood or whatever behind them.

 

[MoreFillerNeeded]

First, I have to say I have no electricians qualifications, so don't take what I say as 'gospel'. However, I've seen several professionally fitted kitchens with the currently in-vogue island units, and many of them have power sockets fitted.

A visit to any large department store will also show you many display cabinets etc on sale that have lighting fixtures.

I would take the approach that you build your unit/furniture as a self-contained item, with secured wiring and all mounting boxes F-rated for the material that you are mounting them on, then connect the whole unit to the electrical supply by way of a 13A plug and switched socket on the wall of the building (this counts as a double pole disconnect and makes it very easy to isolate wahtever you're doing if something goes pear shaped.

Are surface mount boxes F-rated for MDF or chipboard? I've used them in the side of a kitchen cabinet before, but many years ago, before all of this became such a sensitive issue!

 

[Jake]

First, I have to say I have no electricians qualifications, so don't take what I say as 'gospel'.

That goes for all of us to post so far!

This place lost its most well known and helpful electrician to the other forum.

 

[Anonymous]

Jetset

I don't have my IEE regs to hand (they are at work and I am at home this week), but I do not recall anything in the regulations that would prevent what you propose. You need to watch the height of the socket from the floor as I seem to recall the regs stipulate between 150 and 450mm for the floor.

As far as reading matter goes, get hold of the proper regulations (IEE Wiring Regulations BS7671), not a book about them as they contain a multitude of design tables and cover everything you might need to know

By the way, the 17th edition came into force and was made available for purchase on 1 January 2008.

PS the IEE changed its name to the IET last year and the IEEE is the American body, not the UK

 

[Jake]

The kitchen island is an interesting one. I guess an electrician can make a reasoned departure from that guidance.

Even the Regs themselves as I understand it aren't mandatory, they are just persuasive in the sense that it is the IEE's collective wisdom and if you are going to depart from them, you'd better have some well thought out reasoned argument to do so).

I'm doing some Part P supervised works at the moment, so I am acutely (perhaps almost too) conscious of the Regs, guidance, and anything else the inspector might throw at me, and taking a very precautionary approach to everything. Not a bad discipline, given that IANAE.

 

[Jake]

By the way, the 17th edition came into force and was made available for purchase on 1 January 2008.

Have you got a copy yet? I can't get hold of one.

It doesn't come fully into force until June, IIRC.

 

[Jake]

You need to watch the height of the socket from the floor as I seem to recall the regs stipulate between 150 and 450mm for the floor.

I think it may be Part M of the Building Regs that you are thinking of - accessibility for wheelchair users, etc? If so, Part M says sockets and switches should be between 450mm and 1200mm off the floor (which would be an awkward clash of guidance otherwise!). But, Part M doesn't apply except to dwellings except for newbuilds, apart from in extensions and material alterations you shouldn't make accessibility provision worse than it was before the work was carried out (so your sockets shouldn't be lower than they were before, etc).

 

[RogerS]

I bought a couple of 'sparky' books recently and can thoroughly recommend them as they address real 'day-to-day' issues for anyone, like myself, needing to know the best and most pragmatic way of doing electrics correctly.

They are :

snags and solutions - part 1 earthing and bonding

snags and solutions - part 2 wiring systems.

Excellent reading.

 

[andrewm]

Jetset
As far as reading matter goes, get hold of the proper regulations (IEE Wiring Regulations BS7671), not a book about them as they contain a multitude of design tables and cover everything you might need to know

For domestic use the On Site Guide is contains all the tables and formulae that I have needed. The full wiring regs is both large and expensive and includes a lot of stuff on industrial wiring and 3-phase work so is probably OTT for what we are talking about here.

Andrew

 

[andrewm]

Even the Regs themselves as I understand it aren't mandatory, they are just persuasive in the sense that it is the IEE's collective wisdom and if you are going to depart from them, you'd better have some well thought out reasoned argument to do so).

I think that they are now. You are right that they weren't but Part P basically says that to comply with Part P you must comply with IEE regs. Most of the actual Part P document deals just with the extra paperwork that is involved with compliance.

Andrew