What Dimmer Switch will I need?

[zappastix]

Hi

Around 4 months ago my son removed a 3 way normal light switch from the sitting room because he was plastering.

I need to replace the switch with a dimmer switch, but I have a problem.

My son cannot remember how the wiring went, and I can't figure how it even worked in the first place.

This is what used to work on the 3 way switch;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Switch 1- made one ceiling light work

Switch 2 - made the second ceiling light work

Switch 3 - made 4 wall lights all work at the same time

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is the wiring I've got;

2 cables coming in - both twin & earth.

I want to get a 3 way ???? 400 watt per gang dimmer switch.

The new lighting I'm getting is;

4 wall lights (total 8 bulbs max 60 watt per bulb) but I'll have to fit 40 watt (8 x 40 = 320W) which is OK for the 400 watt gang.

2 ceiling lights - 3 x 60 watt each - total per gang 180 watt.

MY QUESTIONS;

Do I need a One Way or a Two Way Dimmer Switch?

How would I wire this up?

The black wires have no 'red' tape attached.

Twin & Earth: Black/Red/Earth

Any help would be appreciated as I cannot fathom how to split the power for 3 individual feeds.

Thanks in advance.

Stephen

 

[ban-all-sheds]

This is what used to work on the 3 way switch;

I take it that you mean it was a 3-gang switch, not a 3-way, i.e. there aren't two other locations where the same lights can be switched from?

I want to get a 3 way ???? 400 watt per gang dimmer switch.

I expect you want a 3-gang one.

Do I need a One Way or a Two Way Dimmer Switch?

You just said you wanted a 3-way...

Assuming that there's only this 1 location with switches, you want a 1-way, but a 2-way can always be used as 1-way if your chosen switch is only available as a 2-way.

Any help would be appreciated as I cannot fathom how to split the power for 3 individual feeds.

Almost certainly one core of one of the twin & earth cables (probably one of the reds) is the permanent live, and the other 3 cores take the 3 switched lives to the 3 sets of lights, and the original switch would have had all the COMs linked together with short pieces of wire.

You just need to identify which of the 4 cores is the permanent live, and by far and away the easiest way to do that is with a multimeter.


PS - you've had no lights for 4 months?

 

[sparkwright]

is there a back box flushed in the wall?

if so is it a 2-gang one (the type a double socket would use)?

and is it deep enough?

are any of the ends of the wires doubled over by any chance?
this would possibly help us identify which are the switch lives and which is the perm live.

 

[zappastix]

Thanks for your help.

We have been using table lamps - a lot of work has been going on, just getting to the point where I can fit the new lighting.

Yes there is a 'one double' metal pattress already in the wall (flush).

The old light switch was just like a regular double light switch, but it had three switches.

I have just tested the wires with one of the testers that light up when near power.

Both incoming T&E have power.

Am I on the right track;

I'll provide power to the 3rd light switch with a link of wire FROM a red wire.

Then run a link from the neutral.

Am I right in saying that I do not need to earth this LINKED connection because there are two earths already?

Thanks again.

 

[ban-all-sheds]

I have just tested the wires with one of the testers that light up when near power.

No - you need a multimeter. Those proximity testers are notoriously unreliable.

Both incoming T&E have power.

As I said - unreliable. You can't have a permanent live in both cables, as that would only leave 2 conductors available for switched lives, and you had 3.

Am I on the right track;

No.

I'll provide power to the 3rd light switch with a link of wire FROM a red wire.

You'll need strappers to the other 2 COMs, and your switched lives will be the other red and the two blacks.

Then run a link from the neutral.

There are no neutrals - you should spend a bit of time reading up on how lighting circuits work.

//www.diynot.com/wiki/electrics:lighting

Am I right in saying that I do not need to earth this LINKED connection because there are two earths already?

Don't try to earth a live conductor - that way lies sparks and bangs and blown fuses and damaged wires.