changing one gang dimmer switch.

[alex30]

Need to change my dimmer switch in livingroom. It is the only switch that controls the livingroom lights. On taking out the old switch I see their are 3 wires which were connected to it. There was the common wire, going into common terminal, and then 2 other wires both intertwined and going into the L1 terminal.

My problem is that a modern dimmer switch will not allow 2 wires going into the L1 terminal as the terminal is not big enough. What is my BEST solution. Can I just connect any one of the two wires into the L1 terminal, and just simply cap off the unused wire. Or should I junction these 2 wires together and feed them into L1.?

If I am to junction the 2 wires whats the best device in Uk to do this??

Also how much clearance does the switch need when positioned inside the pattress socket box. My pattress box is 20mm and a standard switch about protrudes about about 18mm into it. Should this be fine.

Any advice at all would be greatly appreciated.

Alex.

 

[alex30]

To update I believe the reason the two wires were intertwined was that this switch was feeding another switch in another room. Now that I have separated the 2 wires, the light in my bedroom doesn't work. So how does this new information help. So I need to keep these 2 wires connected together and then feed them into L1. Whats the best way to do this, a modern L1 terminal will only accept a single wire?

 

[eveares]

Just use a 5 amp screw terminal block to join the two wires together as they were originally and then run a single wire from the terminal block into L1 on the switch.

 

[eddiewakey]

I've never seen a light switch you couldn't get two cables in?????

 

[securespark]

When you say "intertwined", do you mean twisted together?

If so, snip off the twisted bit and put the (now restripped and straight) conductors into the terminal side by side.

As an aside, if the feed to the next room goes when you split these wires, they should go to common and the switched feed to the light to L1.

It will still work the way it is, but the other way is standard practice.

 

[alex30]

Thanks for all your help. Securespark Yes intertwined meant I was meaning twisted together. I don,t follow your later point about when the feed to other room goes when I split these wires. What should happen to the 3 wires, which goes to common and which to L1.???

 

[securespark]

If the two wires that WERE twisted together caused the light in your bedroom to go out, then these wires should go to Common and the third wire that was on its own should go into L1.

 

[alex30]

Securespark. So your saying that the old switch was wired up in the opposite way it should have been. But the lights worked perfectly for many years.

 

[flameport]

But the lights worked perfectly for many years.

They will work either way.

With a single pole switch (2 terminals), it makes no difference which way round the wires are connected.
Some people like to put the supply in COM and the load in L1. However electrically it makes no difference to anything.

 

[bernardgreen]

I don,t follow your later point about when the feed to other room goes when I split these wires.

One of the two "twinned" wires brings power ( the supply ) to the switch, the other wire takes power further to another switch. The third wire, Switched Live, takes power to the lamp when the switch is on.

Some people like to put the supply in COM and the load in L1.

My preference on a single switch is to put supply to L1 and take the switched Live from COM. This way L2 ( if fitted ) does not become Live when the lamp is OFF

 

[securespark]

Securespark. So your saying that the old switch was wired up in the opposite way it should have been. But the lights worked perfectly for many years.

Did you miss my post?

As an aside, if the feed to the next room goes when you split these wires, they should go to common and the switched feed to the light to L1.

It will still work the way it is, but the other way is standard practice.