"A K" wrote
| I have a house that is 1 year old. In the lounge I have 2 bog
| standard ceiling pendants. I have bought some new light fittings and
| got an electrician to come and fit them (yes I am a hopeless girlie
| when it comes to DIY!). When he unscrewed the pendants he had found
| that the hole had been filled completely with expandable foam
| together with all the wires. ...
| he told me that I should contact the builder and ask him to sort it
| out as this was not up to NHBC standard, apparently some unscrupulous
| builders get their electricians to do this to secure the fitting when
| there is not a joist present to screw the fitting to. He said that
| NHBC will make them lift the bedroom floor and put a joist in!

They should put a 'noggin' in between two existing joists to screw the
pendant into. It is absolutely shoddy workmanship though, and makes me
wonder what other little corners they've cut.

| Can anyone tell me if this is correct? I am concern if having the
| wiring coated and encapsulated in this stuff is a fire hazard.

It's probably not an immediate go-up-in-flames-tomorrow hazard[1], but it is
definately bad practice. Wiring should not be run through insulating foam
like that because it can derate the current-carrying capacity of the cable;
this is unlikely to be critical as lighting circuit cable is usually
generously-sized anyway. But if the foam has a chemical reaction with the
cable insulation that could be rather nasty longer term.

Owain


[1] But you will check your smoke detectors before going to bed tonight
won't you. All usual disclaimers apply.