Junction boxes in a cavity

[cpvh]

Our builder tucked some live junction boxes into a cavity wall and has plastered over them.

How much of a problem is this likely to be (if at all) and in what time frame?

[Dave Plowman (News)]

If the connections within that JB have been correctly made and the circuits not overloaded, it shouldn't be a problem.

[John Rumm]

What kind of JBs?

If they contained maintenance free terminals, then nothing to worry about.

If they were the screw terminal kind, and the circuit is lightly loaded

- then not to the wiring regs, but probably nothing to worry about.

If screw terminals, and a circuit subject to intermittent high load, then more of a concern.

The reality is there are countless examples out there installed and causing no serious problem. However if you have concerns then discuss with the builder.

[newshound]

+1, but also is it *really* a cavity wall? Is it insulated? If so, this *might* increase the overheating risk. If not, then at least there is no real fire risk if it does go t*ts up.

[Brian Gaff]

Problem will be if any of the screws work loose and need to be tightened. Brian

[Dave Plowman (News)]

Wonder how many JBs are in a floor void with expensive floor covering that can't be lifted without damage?

Properly tightened screws don't work loose.

[cpvh]

Thanks all,

They were screw type afaik, circuits don?t get a lot of use.

I?ll put exposing them and swapping them for no maintenance ones on my round tuit list.

Builder is long gone (thank goodness!!)

[Andrew]

They need to be properly crimped and shrink-sealed if they are no longer accessible.

[Andrew]

How did he tuck them 'inside the cavity' ?.

The cavity should be inaccessible from inside or outside if it has been built correctly. Only if holes were left would this be possible and it sounds like piss poor construction detail.

Or, do you mean transformers or junctions boxes for ceiling downlighters, being pushed up into the ceiling void above the plasterboard ?.

[Stephen]

I've seen *far* worse....

The previous houseowner of my house wanted to convert one of the two integral garages to an extra reception room.

Example no 1:

There was just one double socket in this room. So he proceeded to remove the existing double socket which was on a 32A ring main. No problem , they then wired in two brown round 32A 3 termninal JBs to extend the ring main around the garage conversion in order to fit extra double sockets.

Trouble was, the 2 JB's were in the location of the old double socket. So they got a cold chisel out, chopped a chunk out of the thermalite wall, got two tesco carrier bags, wrapped the JBs in these tesco carrier bags and pushed them into the thermalite wall and plastered over it all.

Example no 2.

There was a garage up and over door at the front and a door at the back which went into the kitchen. Obviuously there were 2 way light switches at both ends of the garage, A new doorway was created from the hallway, the back door and the up and over door was then bricked up. So a cable was run from one of the two existing light switches to the new doorway where a new light switch was put. The two original light switches wehere then plastered over!

Example no 3.

There was a consumer unit halfway up the wall at elbow hieght. They decided to move the consumer unit up to ceiling level. The meter cuboard was on the other side of the wall. So they bought in some new 100A meter tail cables to replace the existing meter tail cables so that the CU could go up higher. The meter cables came from the meter cupboard, through the wall into the garage and then clipped up the wall internally. This was then covered over with PLASTIC capping and then plastered over.

Just imagine someone hammering a picture nail into the wall. ALl there would be to protect them from the national grid would be a 100A cut out fuse!. ALl have been sorted out by myself. :-)