Problem Replacing dimmer with standard

[paul_f]

Hi,

I'm trying to replace a dimmer switch with a standard switch. The dimmer made a loud humming noise, and the lights (halogen) flickered badly. However i can not get the new switch to work with this fitting (i have tested it works on others).

I think it's down to my wiring, so please help if you can.

There is only a single light, although there has always been 2 switches on the fitting. There are 3 red wires and a black wire (it has an extension plug on it and not currently connected). Basically I can't get any combination of the three red wires to work, although the dimmer switch does operate as described.

The switch has 2 fittings L1, L2 and common on both.

 

[Spark123]

I am confused to what you are doing and where all the wires are, I take it you are replacing a 2gang dimmer switch? Or do you mean 2way? I don't follow what you mean by extension plug? The new switch sounds like a 2gang, 2way switch. How were the wires connected to the old dimmer switch?

 

[paul_f]

So Basically,

I installed a new halogen light fitting, which in turn caused problems with the dimmer switch buzzing & light flickering. I thought i would try a normal on/off switch as the halogen may not be compatible with a dimmer(?).

Problem is i can't get the on/off switch to work in this socket, and think it's because of the way I wired it. I think once upon a time there were 2 light fittings which explains the number of wires in the box. I dont know which wires go where anymore, and need advice to get it running.

Just to confuse things more there was also a loose wire which joined the 2 gang's somehow.

Sorry for the poor quality (hard to take photo with lights off ) , but maybe these images will help:





p.s. Thanks

 

[Taylortwocities]

Looks like all of the black (neutrals) are joined together in a terminal block? Leave them like this.

One of the reds will be the live feed. You will need a test lamp.
Careful you'll need to do this with the juice switched on
TURN OFF THE POWER AT THE FUSEBOARD
Connect one end to the black leads and try each of the reds. TURN ON THE POWER EACH TIME When the test lamp comes on you have found the live feed. (You could also use one of those nasty neon screwdrivers...)

TURN OFF THE POWER AT THE FUSEBOARD

The red you have identified needs to go into the common (C) terminal on your switch and you'll need a short length of red wire to link fron one C terminal onto the second one.
You are now left with two red leads. These should feed your two ceiling lights. Connect one into L1 on one switch and the other to L1 on the other switch.

TURN ON THE POWER

Should now work

Let us know how u get on and next time please make a note of where wires go before you disconnect them.

 

[Spark123]

Was it a single dimmer switch originally? Were all 3 red wires connected? How many black wires are there?

 

[paul_f]

Thanks guys,

I will give it a go tomorrow. Yes, i most certainly learnt my lesson

 

[Spark123]

BTW, you need a grommet where the cable enters the back box. Can you pull the cable down a bit so the grey sleeve enters the box. I take it you had your camera on its side when you took the picture??

 

[paul_f]

Sorry guys, but I still need help with this.

So with my trusty neon screwdriver I found the live wire, and connected as described, but still without luck. (live to common + connecting wire to common remaining two wires to the L1's)

Using the same screwdriver I checked the when each switch was pressed, the L1 connections were also live. Interestingly the light works when the dimmer swith is connected in the same configuration.

However after about 5 mins use the light (and dimmer) buzzes, and oscillates bright and dark (wonder if the lighting filaments get warmed up and misbehave). The lights are 6 * 20w G4 capsules. They used to be 10w but I upgraded them in hope of reducing the dimmer buzz (which it does for 5 mins)

Like I said, I have tested the fitting with another light in the house, and it works fine. Also, not really clear why and where I need a grommet? Feel free to explain it as you would a 5yr old

Thanks
Paul

 

[Spark123]

You need a grommet here:

The grey sheath of the cable should also enter the metal backbox.
I'm not getting at you personally, but those neon screwdrivers should be banned.
Was the old dimmer switch a single gang one? How is it connected to make it work? Your new switch is two gang, i.e. two completely separate switches. Another thing to note is check the labelling on the switch, some new ones have C, L1 on at the top and L2 at the bottom or vice versa.

 

[paul_f]

I see .. presumably to protect the wires from the metal switch box.

The Dimmer switch is also a 2 gang, although the L1, L2 & C are in different positions, i checked they were all connected in the same order.

 

[fireman22]

paul, if you connects the reds together in a connector block, (all three) together in the block does the light work? doesn't seem to make sence what you are saying, "fitting works on another light", i guess you are referring to the switch. if it works elsewhere are you trying both sides of the switch, maybe 1 of the gangs isn't working? anyway if the light works with the dimmer putting all reds together should make it come on.

 

[securespark]

If the dimmer is buzzing, I can only suggest that it is the wrong kind of dimmer for the load.

 

[paul_f]

Ok guys,

I wired all 3 reds together and the light didn't come on. I If i put the dimmer switch back, then it works in the undesirable way described earlier.

Any other ideas what might be causing this, could it be those G4 capsules drawing too much power? Anything else I can check before removing the light fitting?

Cheers
Paul

 

[breezer]

read secure sparks post just above yours

 

[paul_f]

Thanks Guys,

I put the 10w G4's back into the light, and it works with the 2 way switch perfectly now

Now the missus has to find a new excuse to nag.

Thanks again
Paul