Re: Moving a Lightswitch - Cavity Wall

[Roger Mills]

Hi folks,

> > I've moved into a house where one of the bedrooms has been made > smaller via a cavity plasterboard partition. The chunk that has been > taken away is now an extended part of the hall. (The previous > occupants had to do this before selling the house, in order to get > retrospective planning permission for other alterations they had > made.) The only trouble is that the lightswitch for the bedroom is > located on what is now the opposite side of the hall! > > I want to move the lightswitch into the remaining part of the bedroom, > and while I'm quite competent with the wiring side of things, I'm > worried about what I'll do about wooden supports inside the cavity. > If I tried to drop a cable down from above, and it hit a joist higher > than where I wanted the lightswitch, how should I tackle this? It > must be a common problem and I'm hoping it's the kind of thing where > there's a simple solution that electricians use all the time! > > I've already considered: (a) cutting open the wall and replastering, > (b) installing a pull-cord from the ceiling instead, and (c) trunking > on the face of the wall, but none of these sounds very attractive. If > anybody here can suggest something else I'd be grateful for your > comments. > > Sorry if this has been covered before. The FAQ concentrates more on > how to find the cable inside the wall and pull it through the > lightswitch cut-out, and I've searched Google to no avail. > > With thanks. > > John

Most stud partitions which I have come across (or even built!) have horizontal noggins between the uprights at approx 1/3 and 2/3 of ceiling height. If yours is like this, you'll need to get through both the upper frame member (no problem from above the ceiling) *and* the noggin at 2/3 height. This is the fun bit! Unless you remove some of the plasterboard, you will need a very long, thin drill - well it can be 1/2" dia, but needs to be upwards of 3' long. The cutout for the switch is easy - and you can use a hollow-fixing box. It will help if your holes through the top frame and noggin are in line with the switch. You will then need a long piece of stiff wire, fed down through the holes, and retrieved through the switch cutout, to pull the cable through.

HTH, Roger

[Dave Liquorice]

I may have a similar problem when I come to move a bedroom light switch, well actually separate the bedroom light from the hall light but the problem of possible noggins in the stud wall is the same.

I'll go (a). No need to make a big hole. Work out where the noggin is and drill through the plasterboard at a shallow angle and continue through the noggin. A 1/2 to 3/4" hole is easy to fill with a bit of stiff polyfilla.

\ \\ \ +\ ----+ \\ \\ +---\\-+

[PoP]

Alternatively, whilst the drill bit is still inside the wall after drilling thru, tape some strong string to the end and pull the drill up. That way you don't have to fish around with wire trying to fit it thru holes which were previously drilled.

Then once you've got the string you can pull thru the cable from either end.

PoP

[Christian McArdle]

Use a stud detector to find the noggin. (These are the short horizontal members. There will be one or two in the wall). If you haven't got a stud detector, drill a hole near where you suspect it may be from tapping. Insert a piece of stiff earth wire bent at a 90 degree angle. Twist the wire and feel around until it hits the noggin and you can work out where it is.

Then make a hole (i.e. 4cm x 4cm) in the plasterboard just above the noggin. Drill through noggin with a large bit, easily large enough to take the cable.

To get the cable down there, use a piece of string with a plumb weight on it. Drill a hole large enough to take the weight in the top rail from the loft above. Drop the weight down inside until it hits the noggin, but keep the string taught. Poke around for the string through the hole you made next to the noggin with a piece of spare earth wire with a hooked end.

Once you have retrieved the weight, tie the cable to the string at the top and pull the cable through. Have someone feed at the top whilst you pull the string. Once you have retrieved the cable, feed it into the hole you drilled in the noggin.

Now cut the large hole for the light switch, remembering Part M heights if they apply to your building. Keep feeding the cable until it passes the hole, or you can reach round inside to get it. Install a dry lining box, install the switch and pull the cable back up to remove most of the slack. Fill the plasterboard hole around the noggin with plaster. Repaint.

Christian.

[John Prentice]

Thanks Christian, I think I'll go with this. And thanks to all other respondants, too. I'm grateful for the suggestions.

John