Wiring a dimmer switch - it can't be this difficult!!

I have replaced my two 2 bulb wall lights (4 x 40W) and also the dimmer switch. The wall lights I simply copied the wiring from the ones I took off. There were 2 blue wires twisted together and 2 brown wires twisted together, I put them in the neutral and live sockets. So I ASSUME these are ok!

NB: each of the two new lamps hold 2 x G9 halogen 40W bulbs.

The dimmer switch has terminals L1, L2 and a ~ with an arrow through it (no idea what this means!). I wired this the same as the replaced dimmer switch - red wire to L1, blue wire to '~ arrow'.

When I turned the power back on and tried the dimmer switch - it blew! The new lights didn't even flicker. And the 5amp main fuse blew. I took the dimmer switch out and took the plastic cover off and saw soot on the circuit board. This was a 250W dimmer switch, which I then swapped for a 400W version. Same effect - blew instantly.

I am obviously doing something wrong - please help if you can!! I confess I do not really understand wiring etc but I am not daft (and don't take risks) but I thought this was a straight replacement job!

Many thanks,
Martin.

sounds like you have a short on the cct

i wonder if you have crushed a wire behind new lights

oh and are there any other wires at switch

Are you absolutely sure you connected the new wall lights up the same way as the old ones? It sounds like there is a short circuit either between live-neutral or live-earth. How many cables are there and how have you connected them? How many cables behind the dimmer switch and how are they connected?

Thanks for your quick replies.

The left hand wall light socket has 2 black cables and 1 red. These are marked as neutral, earth and live. The right hand socket has 2 pairs of black cables and 1 pair of red cables.

The lights themselves have 1 pair blue, 1 pair brown and an earth. I have wired the pair of blue wires to the black neutral, the pair of brown to the red live. The green/yellow earth has gone the middle black wire(s) on the plastic connector thing.

I can't see any loose or crushed wires. The sinlge black earth wire has no sleeve as it goes into the thick jacket containing all 3 wires - but I think this doesn't matter?

The dimmer has a blue and red cable, wired to the ~ arrow symbol socket and the L1 socket respectively. The earth wire is screwed to the unit itself (metal case). There are a number of insulation taped bundles - but these were there previously and the lights worked ok then, with the previous dimmer switch.

But the dimmer unit itself blows up! Doesn't seem as though any electricity is getting through to the lights!

The earth wires should be sheathed with a piece of yellow/green stripe sleeving. You haven't screwed the new fitting through the cable have you? Secondly I have seen new fittings with short circuits on before, you could probably do with an electrician with an insulation resistance meter to check the wiring and the fittings.

the ~ is just the common L1 is your switch

deffo sounds as if you have a S.C. somewhere,

ELZ4742 said:

the ~ is just the common L1 is your switch

deffo sounds as if you have a S.C. somewhere,

Click to expand...

Yeah - it sounds like it. If the dimmer keeps blowing would the short be there or at the lights? The lights have never worked since I installed them.

Thanks.