Switched Lighting

[Tucks2526]

Please can anyone assist, I am pulling my hair out. Our electrician (who I cannot get hold of anymore) wired up the kitchen lights on a 3 way switch. 2 of the switches work 2 sets of ceiling lights but the 3rd has been left for the cabinet lights which I have put in. Problem:
Cabinet lights = Live + Neutral.
3 way switch = 2 x (Live + Switched Live) for ceiling lights that work
+ 1 x Live + Switched live cables not connected.
If I connect the Live + Switched Live to the lighting switch (with the other end connected to the cabinet lights) and use a bridging cable from one of the other 2 working switches the cabinet lights do not work or both live and neutral become live. Complicated I know but is it due to a missing neutral connection? There is no neutral cables in the wall switch and I don't know what he did in the ceiling? He mentioned a GRID system????
Can anyone assist, Many thanks.

 

[jj4091]

I presume you mean a 3-gang switch, with only one switch controlling each set of lights & that it is made up of 3 separate switches in a frame(grid switches) as opposed to a moulded plate. It does indeed seem that you are short of a neutral for your cupboard lighting, but it is impossible to tell you where you will get it from with the info you give. Did the electrician not leave a junction box in a discreet position for you to connect them to? How are you picking up the switched live that is connected to the switch?

 

[Tucks2526]

Yes, it is a 3 gang switch with one switch for each set of lights. Not sure what you mean by grid switches but on the back of the 3 gang switch are 3 independant conectors, one for each switch, each with a conector at the top and 2 below (L1 & L2 I think). I presume the working lights which are conected Live + switched Live (to L1) are connected in the ceiling to a junction box which contains the earth, neutral and live, ie the 2 wires (per switch) are coming down the wall are just the live and switched live only. The electrician didn't leave a junction box (not that I know of) and I think the cable he left for the cabinet lights loose for me to connect just go to the 3g wall switch and are connected like the others (live + switched live). ie I think he has just left one piece of cable, loose at one end and connected to the wall switch at the other end. A small piece of wire has been used to bridge from the live on one of the working switches to the live on this 'un-working switch which obviously then makes it live.
Because there appears to be no available neutral to connect to in the wall switch, the only other option I was think of doing is connecting to an available 5amp socket I have under the units (FCU I think) which is off the ring main to pick up the neutral. One end would go to the cabinet lights and the other to the wall plate in order to make it switch.
Apologies as I'm sure this all sounds a bit confusing but your help is greatly appreciated. Many thanks.

 

[jj4091]

Do you have a meter or some other method of determining what the potential across switch 3 is? Borrowing another neutral from a different circuit is not a good idea & it is difficult to guess what you have when you say a 5A socket(FCU you think) as they are 2 distinctly different things. Can you post some pics? It sounds like the spare lead you mention is intended to be a switched live & neutral with the live linked from one of the other swiches, but you need to be certain that is the case before connecting anything.

 

[Tucks2526]

I'm not sure what you mean when you say 'the potential across switch 3' and unfortunately my didgi camera is broken. I have however done some tests and I don't think the wall cable is a straight run to what appears from under the floor. It must connect somewhere else or be put into another juction box but unfortunately the new kichen is down and new floor laid so I can't get under it to see.

When you use a bridge wire from one of the existing lives in the socket to switch 3, this makes the live and neutral at the other end of the cable both LIVE.

I have also put a plug on the end of the cable to see what happens in the wall switch and the 'switched live' (Blue with brown tap over it) becomes live when turned on - so must be the same cable. when the switch is flipped, both live and switched live become LIVE. If this cable was one straight run this would effecively (when the switch is pressed) link the live back up to the neutral in the plus and flip the circuit breaker but it didn't. I can only asume the the 'live' (brown cable) in the wall switch goes somewhere else.

Is it possible that this cable in the wall switch is split somewhere under the floor? The elecrician mentioned a 'grid' as we were going to have dimmers originaly but I'm not sure if this is the case.

Geting very confused, Many thanks