Filling deep holes round electrical sockets

[mdnorth]

Hello, I have had the kitchen sockets replaced (all part p marvellous) as part of installing a new kitchen. I have a double socket and a cooker point to tile round, fine no problem with that. However I have substantial holes around both, which would be impossible to cover with a tile without anything behind. I know expanding foam can effect wire insulation and my efforts with making 3d plasterboards shapes to fill the gaps; has come to naught. From previous work it looks like the old wires were plastered in with multifinnish plaster ? However is this OK ? I would imagine mixing thick plaster would require the power to be turned off as it will be moist ? Greatful for any response

 

[John D v2.0]

It's polystyrene that's a problem for PVC electric cables, expansion PU foam is no problem at all. Although if a cable is heavily loaded, the extra insulation would cause the cable to get warmer.

 

[EFLImpudence]

From previous work it looks like the old wires were plastered in with multifinnish plaster ? However is this OK ?

Yes, of course.

If the holes are big, then use cement and filling material.

 

[mdnorth]

Thats great assumed all foam was the same, do I have to worry about ingress into the metal socket boxes as well when I apply, ie would I tape up the holes on the metal back box, spray the foam cut away the excess and then tile over ?

 

[mdnorth]

If the holes are big, then use cement and filling material.

 

[SFK]

mdnorth
I would use Multifinish like you suggested at start (it is only going on the Gray cable isn't it, not any bare wires??) as spray foam can sometimes go everywhere when it is a small hole.
But if worried and hole is not that big get a tub of (expensive) "Deep Gap Filler" from your local shed/shop (there is even a picture of your issue on this one):
http://www.wilko.com/fillers-sealan...gclid=CIDWuoGE4NECFYsy0wod8TEJXw&gclsrc=aw.ds

http://www.screwfix.com/p/ronseal-big-hole-ready-mixed-wall-filler-grey-1-2ltr/95289

 

[mdnorth]

Sorry for the obvious question but is this cement, ie cement, sand and water, or would you use a ready mix interior cement ? I suppose same question is, while the filler is moist turn off the sockets at the consumer unit as well

 

[crystal ball]

I always found bonding good for big holes

 

[mdnorth]

Thats brilliant, deep gap filler, is exactly what I am looking for many many thanks

 

[SFK]

mdnorth,
My pleasure.
Also regarding turning the power off, you do not need to do this because of the damp/wet filler as this should not cause any issues, BUT your should/must turn it off anyway as you need to pull the socket off the wall a bit, to allow you room to make a flat surface of the filler between the wall surface and the metal back box.
sfk

 

[JohnD]

I like sand and cement mortar. Applied with a flat filling knife, you can usually push it over the top of the backbox and it will fall into the gap, then you can tamp it down. It is very cheap, and slow to set so you have plenty of working time.

I would definitely turn off the power and test for dead, and remove the faceplate.

A stiff, dry paintbrush will flick away any mortar or filler that falls into the box.

 

[securespark]

Wonder if they use that Polyfilla in breast implants? Sag resistant...

Well, at least you have something to think about while carrying out the boring task...

 

[securespark]

I always found bonding good for big holes

Yes, I always used to mix mine with a bit of PVA.

 

[sparkwright]

Another vote for bonding coat. Easy to apply, and sets firmly and quickly.

A lot of so-called ready mixed patching plasters are rubbish and don't seem to go off quickly or set very firmly.

 

[ban-all-sheds]

I have substantial holes around both, which would be impossible to cover with a tile without anything behind.

P...-poor work by your electrician, if you ask me.