Dimmer switch wiring problem

jdmorrisn · 11 Aug 2008

Hi all,

First let me brief you that I am fairly capable but things in simple language are better for me than abbreviations.

Basically I have a lounge switch and an outside light switch side by side and I wish to change the lounge light to a dimmer switch. I thought this would be easy since it is only a matter of replacing the wires in the old lounge switch to the same as they are in the dimmer, not so. As soon as I put the fuse back on - bang, the 1.5amp fuse in the dimmer blew. I have this diagram of how I have wired it according to how the old lounge switch was wired, any ideas?

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Can anyone help?

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breezer · 11 Aug 2008

why 3 of the same drawing?

if the dimmer wnt bang its either wired acrross the supply or wired wrong.

sorry but your drawings are too feint for these old eyes

plugwash · 12 Aug 2008

here is a more readable version of the picture, not that I can make any sense of it.

breezer · 12 Aug 2008

oh wire nut? I thought it said wire out

I wonder if the dimmer switch drawing internals are correct?, if not it would explain the Bang.

I am not saying it shouldnt, but i have not seen a neutral connected to a dimmer switch before.

If the dimmer is 2 way (that would account for the 3 terminals) it does not need a neutral

and i dont see why the neutral is switched at the switch (could be double pole though)

jdmorrisn · 12 Aug 2008

Hi again all (don't know why 3 pictures came up).

I wonder if the dimmer switch drawing internals are correct?, if not it would explain the Bang. - Not sure I understand you, why would the internal parts be incorrect to the drawing printed on the side of the dimmer?
I am not saying it shouldnt, but i have not seen a neutral connected to a dimmer switch before. - If this isn't neutral what is it?
If the dimmer is 2 way (that would account for the 3 terminals) it does not need a neutral - what do you mean two way (I told you I am not very good on the jargon).
and i dont see why the neutral is switched at the switch (could be double pole though) - double pole ??

Should I just wire all the neutrals together then and put only live and switched live to the dimmer, ignoring this N on the dimmer?

thanks again.

jdmorrisn · 12 Aug 2008

Hi Breezer,

also you mention that why is the neutral switched at the switch - is this not correct? They should all be just linked together by a wire nut for example in the back box? And only the live and switched live connected to the switch?

It's just that these switches all have a red tab (position 1) and a blue tab (postion 3) at the top and two white ones at the bottom (position 2 and 4).

This switch is different in that it has a light on the switch itself so that you can see in the dark when the light is off but when you switch the light off it goes out.

It has a wiring diagram printed on the side which shows position 1 to position 3 is the switch and position 2 to position 4 is the light - but what would be connected to position 2 and 4 in order for the bulb to work correctly?

breezer · 12 Aug 2008

is there anything else you would like to tell ?

are you sure?

The fact the dimmer went bang proves something is wired wrong.

I am not familair with the switch you have, hence my statement of perhpas its double pole.

change the dimmer to an ordainiry swithch and see what happens

jdmorrisn · 13 Aug 2008

Hi Breezer,

I give as much information as possible because I hope it helps.

As I mentioned before there was originally an ordinary switch here which worked fine. But I would hope the dimmer isn't wired wrong internally since it isn't cheap (about £50).

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This is the spec sheet with the dimmer if it helps.

My main concern is what wire should go where in the three terminals? Is this N - neutral or not, what is the symbol (circle with a cross in it, like a lamp symbol)? I tried with all the neutrals together and only live and switched live connected to these terminals but it didn't do anything when wired like this.

One other thing I checked the voltage with a voltmeter last night and it shows 298v, perhaps this is the problem, is this normal? And how can it be almost 300v when it is supposed to be 240v??

jdmorrisn · 14 Aug 2008

Does anybody have any ideas how to wire this?

The last one doesn't work after it went bang (even though it has 1.5amp fuse in to protect it) but I managed to get a replacement and before I do the same to this one I would appreciate some input on how anyone out there thinks this should be wired or can see by these spec sheets what wire should go where in the dimmer?

Help guys. What do i do?

breezer · 14 Aug 2008

last drawings you posted are also too small for these old eyes

jdmorrisn · 14 Aug 2008

Not sure how to make the pictures any bigger :s

I have tried again here on an A3 image jpeg, but it doesn't look that much different to me on screen.

How did plugwash manage to make the picture so big? When I preview and click on the picture it almost fills the screen - does it not do that on yours?

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I'm dieing here, sat looking at wires in the wall (not really there is an ordinary switch there at the moment) and a dimmer and neither are united..

It should be easy, I have earth wires all together in a wire nut, I have the neutral wires all together in a wire nut only left are live feed and switched live to the light, so where do they go on this damned dimmer?

jdmorrisn · 15 Aug 2008

Nobody has any solution - or ideas??

solair · 1 Sep 2008

To me it looks like the dimmer may be electronic and needs the neutral as it has to power electronics in the unit. It does not appear to be switching the neutral, otherwise you would have four terminals ... i.e. Live in, Neutral in on one side and Switched live and switched neutral on the other side.

jdmorrisn · 2 Sep 2008

It's ok, I found the solution on the UK electrics page. Basically live to the L terminal and switched live to the N terminal and all works nicely. The other terminal is for 2 way switching.

But thanks anyway.

Dimmer switch wiring problem

breezer

breezer

breezer

breezer

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