OT - Light switch help

[Pford75]

Have finally fitted one of my wall lights, but it doesn't work...

Prepare for some idiot questions....

Do I have to fit all 4 before I can test or should 1 work in isolation?

There have never been wall lights there before, just wires hanging out of the wall...the wall light itself is basic...just L/N/E connections in a connection block. Haven't fitted to wall yet, so I know that nothing has come loose.

Was wondering if the light switch may be the problem. But this is where I really confused myself..... I have a 2 gang switch (ceiling light and wall lights). The ceiling light works fine. I have 3 cables coming into the switch

1. Switched live (Black w brwn sheath), live (brwn), switched neutral (grey w blue sheath)
2. Live (brwn), neutral (blue)
3. Live (brwn), neutral (blue)

The earths are all connected to the back of the box.

There is also a short connector.

The switch is L1,L2,L3.....can someone explain what connects to where so that I can eliminate the switch connections as the problem?

 

[robgil]

Have you tested for live?
do you know which kind of light ring you have, there are two different kinds? this might be of help,

http://www.diydata.com/planning/electric_lights/electric_lights.php

 

[Pford75]

Have PM'd you

 

[Lime]

Speaking as an old electrician..... you know what I'm going to say.... if you don't understand a circuit you don't know if it may be dangerous and you don't know what you are doing.
New wiring or not, bad installations can kill.
What tests have been done?

 

[Pford75]

Fair point Lime.

This is a brand new installation and was fully tested and signed off for Part P only 2 yrs ago.

We just haven't had the wall lights until now...so have had terminated cables in the walls....only today have I fitted the wall lights.

 

[Flyfisher]

Daft question, perhaps, but have you checked the fuse box? I'm wondering if a professional electrician leave unconnected live cabling in the walls?

Otherwise, do be careful (you know that of course!) and don't make assumptions - or rather, make assumptions if you must but verify them. Sometimes easier said than done, especially without the right test equipment (and I always prefer a proper digital meter to those neon screwdriver thingies).

Otherwise, as the installation is new and certified, a call to the electrician who did the work might be in order!

 

[Pford75]

Thanks FF - Have checked the consumer unit - the ceiling light works fine...so obviously not that.

Loathe to call an electrician out for such a small job...was hoping to be able to sort it (have managed all our other wall lights without problems)

 

[Pford75]

Photo of back of switch - the 'top' switch is working fine as this controls the ceiling lights fine.

 

[MdB]

The black wire should have some brown sleeving wrapped around it. Where is the earth wire?

I'm afraid I'm with Lime on this one, if you don't understand it, you shouldn't be doing it.

Myself, I would never leave unterminated live wires in the wall so would have left them disconnected where they terminate. You will have to find that point.

 

[Pford75]

Earths are connected to the back of the box.

Yes, there is a brown sheath on the black wire out of shot.

The cables were terminated in a chock block

 

[Lime]

Looking at the pictures it is possible that the black and brown wire on switch 1 have been transposed. i.e. the black is the live (line) and the brown the switched live.
Have you tried the wall light with the ceiling light switched on?
Have you checked the voltage on all the cables in relation to earth?
have you checked that the live cross-over wire (brown L1 to L1) has been stripped of insulation at both ends?

 

[Pford75]

I think i've diagnosed the problem.

The wall light points are cabled in pairs...each pair has one point with a single L/N/E cable and the other with 2 cables.

The wall light I am testing is connected to a single cable...with the 2 cables at the other point in the pair unconnected....hence there is no loop.

Assume I need to connect another wall light to this pair before testing further

 

[robgil]

have you checked your bulbs are working?

 

[Lime]

Or use a choc block to connect the two cables together.

 

[MdB]

Earths are connected to the back of the box.

Yes, there is a brown sheath on the black wire out of shot.

The cables were terminated in a chock block

I can see something that looks like it is an earth terminal on the back of the front face. This should be connected to the back of the box as well (with yellow and green sleeving).

I would guess the left hand side of the switches (as shown) is the live connection and the right hand side (black wire and 2 x brown) are the switched live.

The wall light points are cabled in pairs...each pair has one point with a single L/N/E cable and the other with 2 cables.

The wall light I am testing is connected to a single cable...with the 2 cables at the other point in the pair unconnected....hence there is no loop.

Assume I need to connect another wall light to this pair before testing further

I'm a bit worried about what you mean by loop here. Can you draw a diagram of what you think you have? It is probably just terminology but if you want a second opinion, a diagram would help.

 

[Pford75]

Problem solved.

Having connected the other wall light point in the pair with a chock block, all is working fine.

Will crack on and photos soon..

Thanks for the help

 

[FamilyWiggs]

Pf - you need a sleeved earth connection between your backbox and the metal faceplate of the switch. There is a screw connector just visible on the faceplate. You should do this for each switch if not already done.

Do not rely on the screws between the faceplate and the backbox to maintain the earth.

No idea if this is covered in Part P (suspect it is) but am surprised your spark didn't do this...

 

[Pford75]

FW- I do have one connected, I just changed switches hence had not connected....but thx for your concern.