3 gang switch

[granville]

I have recently changed my 2 gang switch which controls a downstairs 1 way and an upstairs 2 way, to a 3 gang to incorperate an outside security light.To achieve power i used a small strap of wire and ran it from the live of the centre light switch.It worked ok for about 6 months but has since stopped working. Asuming that the light was faulty i bought another one which has a pir detector.Wiring this to the existing 3 way i could not get it to work.I then tested the security light with a plug into a socket which worked.Assuming the switch was faulty i replaced it with another one,i got the up and down stairs light to work but still not the security light.I removed the switch and realised that i had it upside down so rewired it as before but right way up.On turning the power back on it sparked and tripped the safety fuse.Before the last resort of calling out an electrician i thought i'd search the web for advice.
I have tested the wires with an electrical screwdriver for live etc...and they are as follows;
1 core has a wire sleeved green which is earthed and a red (not testing live).
Another core has the same,both of these enter the box from the top.
Below this is a core with a red and a blue wire(which both test live)a green earth wire and another bare wire sleeved with green sleeving.
I then have the 3 core coming into the box from the security light outside.
I hope this all makes sense!

 

[ban-all-sheds]

Sorry - makes no sense to me, I'm afraid.

Firstly, turning a switch upside down but keeping the connections the same doesn't make any difference to how it works, so something else must have happened to blow the fuse. And if it was working for 6 months previously, you must have changed something when you started fiddling with it.

A 3-gang switch will have 3 sets of terminals labelled COM (or C) an L1, plus possibly L2 if it's a 2-way switch, and it's which wires go where that matters, not whether the cables enter the box at the top or the bottom.

Secondly, the cables you would normally have will be 3-core or 4-core (core refers to one of the conductors inside a cable, not the entire cable). Either Red, Black and bare earth (possibly sleeved in green or green/yellow) or Red, Yellow & Blue plus ditto bare earth.

What you've described is:

CABLE 1 - 2 cores: 1 Red, one bare

CABLE 2 - 2 cores: 1 Red, one bare

CABLE 3 - 4 cores: Red, Blue, Green and bare

so without a much better description of what these non-standard cables are, where they go, which cores are connected to which terminals on the switch and the light etc, it's going to be very hard for anyone to work out what you've done wrong.

 

[breezer]

Think i have the answer.

Granville, wher did you connect the light to? obviously a cable out side, but what about the other end of that cable where is it, and what is it connected to?

it looks like you have no neutral

 

[BR]

Granville, You appear to be missing a neutral, although if the light worked for 6mts you must have had one sometime. In order for the light you must have two things.
1. Switched live - this is the live wire which the switch turns on and off, you can find this by placing an "electrical screwdriver" up against the various conductors at the outside light and asking someone to flick the switch on and off. This wire should be connected to the live terminal on the light.

2. You need a neutral, in effect this can be taken from anywhere in the lighting circuit.

You should also ensure that an earth wire is present in the wiring for the outside light even if it does not require it (useful if someone were to replace the light)
Don’t rely on the colour coding of the cables. It may be incorrect.
Finally disconnect and remove any other cables you installed which are not needed. If you are left with cables in the outside light Junction box, which you do not need, or know what there are for, simply terminate them (insert them into) using a connector block

 

[breezer]

BR dont you ever read previous posts? i said over an hour before you posted that granville is missing a neutral

 

[BR]

My apologies breezer, my page was not up to date, I hadn't seen your post.

 

[breezer]