Electrical sockets in lower ground floor - breaking the tanking

[legoqueen]

When we moved into our house 8 years ago & renovated the lgf to use as living space, we had the walls tanked as a precautionary measure. The house is on a hill & there were no damp problems but as we were stripping back etc it seemed a good idea. We are now changing the accommodation from this floor to create a swish open place kitchen/dining space with fitted units & integrated appliances. It seems we may have to break the tanking to have sockets installed behind the units for appliances - assume that is okay but are there any electric regulations issues & anyone know of an alternative other than channelling through granite work tops which my DH flatly refuses to consider?

isn't there drylining plasterboard on the room side of the tanking?

was it a plastic membrane, or a black "paint"?

is there a drain under the floor?

will the appliances be under a worktop? (in which the cables or mini-trunking can be surface-mounted because they will not show)

Hi PigletJohn, there is plasterboard, it is a plastic membrane, there is no drain. The appliances are below worktop level, but we think that the worktops are likely to be below the top of the tanking level & the cables will be coming down from the ceiling, otherwise the surface-mounting would be the way forward...

If you used a render or paint-on system then breaking through will be a weakpoint which effectively makes the system useless. If you drylined in board you would only lose a very small amount of space but avoid creating waterproofing issues.

How much did the tanking cost? Because to cut into it you might as well have chucked that money out the window if you break through it! Seems a bit of a waste....

I meant to say that dry-lining in-board would create a cavity for the cables concealed, keep the wall flat and safeguard the tanking/guarantees etc which you would be asked for when you sell but would otherwise have to explain why you waterproofed and then invalidated.

If you have a plastic membrane, I don't know if it could be patched enough to recover its integrity, and I don't know if you could pass cables through holes in it and seal them. Presumably there is a way, but it will be quite specialist.

I'd suggest running the cables down in a corner or to the side of the worktop, and concealing them in (earthed metal) trunking which you can paint to blend in, then run horizontally behind the units, surface-mounted mini-trunking.

If you run cable behind plasterboard, it needs to be in Safe Zones. One day somebody will drill a hole for a knife-rack or to hang a clock.

It sounds like this electrical work is being done in a kitchen, so it is Notifiable.

Thanks, electrician due today so useful to have some ideas to discuss. It would be a shame to lose it if there is another way.

It is a kitchen, does Notifiable mean that it needs to comply with part P? Would these suggestions comply? Thx!

We have the sockets installed into the cupboards next to those the appliances are in. It takes a little bit of the cupboard space but aesthetically it is a good solution and a cheap one. We're in an old cottage and needed to tank up the walls to window cill height and didn't want ugly sockets sticking out above the smooth worktops.

all electrical work in Dwelling Houses in England and Wale "has" to comply with building regulations, part "P" , however not all work is notifiable. Some work is exempt from notification (see table 1, page 8).

Much work in kitchens, bathrooms, saunas, swimming pools etc is notifiable; so is installing new circuits and consumer units.

Not being notifiable does not mean that it does not have to be safe, and an electrician or householder who carried out work that was non-compliant might find himself in a difficult position under some circumstances, even for non-notifiable work.

Thanks, this is quite technical...I am confident that the electrician can self-certify if the work is Notifiable, but is there a question over the prevention of moisture? Although we had the tanking done, this was purely precautionary & we have no reason to think there is excess moisture in the room.

MisForMumNotMaid thanks - not sure that would work as still wouldn't solve the problem of bringing the cables down from the ceiling?

There is a current fashion (though I am not keen on it) for having all the switches for kitchen appliances in a Grid in one place, perhaps near the door, and then running the cables to the individual outlets, many of which will be in the wall behind the appliances. There are extra complications regarding cable length leading to voltage drop, and bunching of cables leading to overheating, both of which can be overcome by calculating a larger cable size, but my biggest objection is that if the switch is not in clear sight adhacent to the appliance, it will not be immediately obvious how to disconnect it. This is tiresome when servicing, but could be much worse in an emergency.

To me, hiding switches in a cupboard and hiding them behind cans and bottles is as silly as putting skirts on piano legs.

I like to see switches naked and unashamed, like taps and cookers.

Just to update - we have ended up happily not having to break the tanking - but the sockets will be in cupboards (sorry PJ!)...relieved to have a solution & the necessary certificates. Thanks to all for the advice.