dimmer switch

[jim bob]

I am replacing a 2 gang light swich in the kitchen with a dimmer switch. When I opened the switch plate to replace it with the new one, I thought all I had to do was replace the existing wires into the new switch, but when I opened the switch thinking I would find 2 red wires and 2 black wires so I would know what was live and what was neutral, what I found was all 4 wires going into the switch was red, 2 into the top and 2 going into the bottom with a red wire connecting the bottom 2. I think the bottom connections must be the live do not want to do anything withouy advise. any comments on this would be helpfull. thanks in advance. jim bob

 

[delmel]

They are all live
Live feed and switch live. There are no neutrals connected to a switch or dimmer.

 

[breezer]

change it like for like, and yes there are no neutrals, also note my signature

 

[ban-all-sheds]

I am replacing a 2 gang light swich in the kitchen with a dimmer switch.

The lights are suitable for dimming, are they?

I opened the switch thinking I would find 2 red wires and 2 black wires

A reasonable expectation..

so I would know what was live and what was neutral

As the others have said, the black at a light switch is switched live, not neutral.

what I found was all 4 wires going into the switch was red,

Red/Red cable is sometimes used for switch drops in lighting circuits

I think the bottom connections must be the live

Probably - but this is one of those instances which show that when working on electrics a multimeter is as essential as a screwdriver...

 

[felix]

Somebody's got to ask this sooner or later ---

Jim bob, have you got any earth wires in there?

 

[jim bob]

Somebody's got to ask this sooner or later ---

Jim bob, have you got any earth wires in there?

 

[jim bob]

Yes felix, the earth wires are connected to the back box.
thanks for your reply.


yes the lights are gu 10s and are suitable for dimming, thank you for your advice.

jim bob

__________________________
moderator

please note 10a

 

[ban-all-sheds]

yes the lights are gu 10s and are suitable for dimming, thank you for your advice.

Sorry if this another "of course I have" question - have you checked what the rating of the dimmer is when it's used on halogens? A lot of them won't handle the full load that they can take with ordinary incandescents.

 

[jim bob]

Yes the switch is 2*250watts I am only using 1*200watts and 1*150watts.
thanks for your reply.
jim bob

 

[Damocles]

You have 200 watts and 150 Watts respectively of halogens? The point BAS was getting at is that many dimmers require to be de-rated 50% if used with halogens. So your 250Watters would only be good for 125W each. (presuming you have not halved the rating already)

If you have a neon screwdriver it should tell you which is live and which not. They are not wholly reliable, but you should get a bright glow on the wire which is live and none on the others (which are shorted to N through the lamps)

 

[kendor]

You have 200 watts and 150 Watts respectively of halogens? The point BAS was getting at is that many dimmers require to be de-rated 50% if used with halogens. So your 250Watters would only be good for 125W each. (presuming you have not halved the rating already)

If you have a neon screwdriver it should tell you which is live and which not. They are not wholly reliable, but you should get a bright glow on the wire which is live and none on the others (which are shorted to N through the lamps)

it is the reliability of neon screwdrivers and their use in this context that should be questioned as they can totally mislead due to spurious lighting of the neon indicator and as such should not be used for tracing and identifying cable purposes.

 

[jim bob]

Hi Damocles, the dimmer switch is suitable for gls or halogen lamps at full rating and lv electronic transformers.
thanks for your comment.
jim bob