replacing switch. 2 reds, 1 black?

[karl210]

Hi,
sorry this may be a stupidly obvious question but please bear with me. one of the bedrooms has 1 light with 3 bulbs and 1 switch, simple. ive just gone to replace the bulbs with led bulbs but as i took 2 bulbs out the remaining one came on. I wanted to fit a dimmer switch also so thought the switch may be wired wrong.
As ive taken the switch off there are 2 red wires and 1 black. 2 reds go to the same terminal and the black goes to one of the others.
How should i wire up the new light switch to avoid this issue where the light is getting a little bit of current.
thanks

 

[bernardgreen]

You have to wire the switch as it was wired before. One red will be bringing Live to the switch, the other red will be taking Live to supply another room. Hence they must remain connected together. The black is taking Switched Live up to the lamp.

Be aware that most dimmers have a minimum load and may not work with a small wattage of lamps.

If the LED lamp(s) are glowing when the switch is off then you will need to fit a snubber which is a capacitor and resistor in series across the lamp

A convenient source of the snubber is the contact supressor sold by Maplins

http://www.maplin.co.uk/p/contact-suppressor-rg22y

This has a 0.1uF capacitor which is a bit of an over kill but better too large than too small.

There are other suppliers.

 

[karl210]

brilliant thank you. we have the led's in another room with a dimmer and that works fine so should be ok there, yet that socket has the usual wiring. i will try the dimmer switch and see how that goes and if they still remain on inwill pop down to my local maplin and grab one of them capacitors. Would it just go on the black wire from the switch to the light?

 

[Alex123-4]

Hello
Just a word regarding fitting a dimmer to LEDs
A normal dimmer switch may cause flickering etc so its best to ask for a TRAILING EDGE DIMMER and that way you should avoid flickering and such like once you apply power. Maybe you know this already but in case you dont its worth noting.

Halogen bulbs are ok on a normal dimmer its just LEDs which may give you problems
Good luck sorting your lights out
Kind regards
Alex

 

[bernardgreen]

Would it just go on the black wire from the switch to the light?

It has to be connected to the lamp, one lead to the Neutral and the other lead to the Switched Live. You will need to get a bit of sleeving to cover the leads to prevent any shorting in the light fitting.