Replacing sockets and switches

Viper_7

weekendwarrior wrote: »

The black wires in the terminal block in the picture are the neutrals.

How do you know from looking at a picture?

The previous owner could have bodged the job and not used the correct colored sheaths - or not placed a red sheath on it, if it's actually live when used in parallel with other switches.
Can't just assume it's neutral from a picture but it does look to be.

vipes

Sammz

weekendwarrior wrote: »

I really think that you don't need a sparks to change a light switch and if you do call a sparks to change a light switch he will either charge a fortune- call out fee etc or just won't bother turning up.

The black wires in the terminal block in the picture are the neutrals.



There is an earth wire in that picture already, if your new switch does not require an earth then it should be connected to the metal back box.

If your instructions say that you have to insulate the earth wire then they are clearly wrong. A metal back box with a plastic fronted switch still requires earthing.

I have more than one switch/socket, I have 11. The instructions are on the back of the packet of the light switch I bought in B&Q.

TimBuckTeeth

weekendwarrior wrote: »

........
There is an earth wire in that picture already, if your new switch does not require an earth then it should be connected to the metal back box.

If your instructions say that you have to insulate the earth wire then they are clearly wrong. A metal back box with a plastic fronted switch still requires earthing.

The incoming cable earth should be connected to the backbox earth terminal and the earths from the other cable(s) connected there also. I assume there is a short earth wire connected from the back box to the metal switch, if so it is not required for a plastic switch and can be insulated.

Incisor

weekendwarrior wrote: »

... The black wires in the terminal block in the picture are the neutrals.

WARNING: It is quite unusual for black wires in a switch to be neutrals [but not unheard of]

Exactly why people are warning against getting DIY advice on electrics from an internet forum

shown73

I've just done most of mine, but it can be a bit of a sod, some of the wires are very inflexible and awkward, and it would be very easy to make a mistake, for example when pushing the whole assembly back into its socket. If you have a number of switches/sockets to do and are not sure, why not just ring around and ask for a few quotes, at least then you would know what you were up against. Might not be as bad as you think. Don't take a chance, the life you save might not be your own......

weekendwarrior

Incisor wrote: »

WARNING: It is quite unusual for black wires in a switch to be neutrals [but not unheard of]

Exactly why people are warning against getting DIY advice on electrics from an internet forum

There are a couple of ways to wire a lighting circuit, one way is the loop in method where you run a cable from the consumer unit to the first ceiling rose and then make all the connections at the ceiling roses, so you have a neutral at the ceiling rose.



The other method, which is not as common is to take the circuit wire from the consumer unit to the switch and then connect the neutral wires together at the switch rather than at the ceiling rose. This is the arrangement that the original poster has on that particular light switch.

coolman_2

I think it a bit harsh saying that sparks are unreliable as some are reliable and very helpful at sorting out the job quickly and for a fair price and it is only a few who are lazy and dont turn up

andrew-b

Weekendwarrior, as has already been pointed out you can't possibly be 100% sure how the OP's switches are wired. Yes the 2nd method you refer to is most likely the method used (i have one switch like it) but there's no guarantee that standard practice has been followed. Different people may have worked on the same circuits at different times and might have wired things wrongly. Or seperate circuits on different fuses at the consumer unit linked together. A black crayon may be black, but a black wire isn't necessarily neutral! Electrics have to be treated with respect and you have to assume everything may be live.

How would you feel if you knew someone had died because of the advice you gave them? It really is no joke - please think really carefully what advice you give. You may well be right...but what if your not?

Fortunately it appears the OP is doing the sensible thing and getting someone in.
There are many electricians out there who likely cram in multiple jobs like this every day. Just because one electrician isn't interested doesnt mean none are!