New Dimmer Switch - All Blacks connected...Help!

[Bob26]

I'll try and keep the explanation simple in the hope that some one can simply explain...Thanks.

New house. Light switch in lounge being replaced with new dimmer. 2 switches on original plate - on/off, one for each ceiling light - two lights in total.

Puchased new dimmer switch - as I have done previously. Unscrewed the old plastic switch plate with an aim of using same connections in new dimmer.

BUT..when I see the wiring I am confused.

3 main cables coming in. But all 3 black wires miss the switch and are connected separately with a plastic connector?

Switch wiring looks like this:

Cable 1: Red to COM in 1st switch, with link wire to COM in 2nd switch
Cable 2: Red to L1 in 1st switch
Cable 3: Red to L1 in 2nd switch

(I'm pretty sure it was the above, but am writing from memory at work)

The main issue is what to do with the black wires, becsue when I wired up the new dimmer leaving them as they were...nothing worked?

Please help...what to do with the black wires???

 

[sparkybird]

Hi Bob

This arrangement is called an in line or feed through switch, where all the neutrals (black) are blocked off together. If the light's aren't working, I reckon you must have muddled up the lives (red). If you have voltage probes, you could switch the circuit off, take out all the lives, separate them, switch the circuit back on and then test which one is live (only one should be) . Pop this into the common and link across to the other common. Then pop the other two reds into the 2 L1 terminals and that should do the trick

Good luck

SB

 

[Bob26]

Many thanks, will give it a try tonight....so I can ignore the blacks and leave them as they are then?

 

[sparkybird]

Yes, and make sure they have a good connection together with some connector block. I also wrap them up in some insulation tape too!

SB

 

[RF Lighting]

I also wrap them up in some insulation tape too!

Why?

 

[Spark123]

So the next spark along has to contend with a horrible sticky mess

 

[Lectrician]

Insulation tape should be banned.

The only thing it should ever be used for is to help with pulling in cables etc...........and as a temporary plaster on a finger!

I hate seeing taped chocky blocks.









Sparkybird - I would call it 'looping through the switches'.......not sure on your names - although I knew what you meant

 

[securespark]

All blacks...why have you got a rugby team connected to your light?

 

[sparkybird]

I just followed what I'd seen done before - baaaaa - but I guess you don't have to wrap them up...

I think this method of wiring is called a few different things - glad you got my drift. BTW one of my old tutors at college tried to convince me that this way of wiring switches was 'against the regs' but when pressed he admitted that it was just that 'you wouldn't expect to see it normally' - god know how I managed to pass with him as a teacher!!

SB