Making a switch two way..

[corax]

Can someone help answer this for me?

I have a 2 gang switch in my garage. The switch on the left operates a motion detect led light outside the garage, the switch on the right operates two led strip lights on the garage ceiling.

If I enter the garage from the back door, I have to cross the garage in the dark or use a torch. I'm looking to add a switch next to the back door to operate the strip lights. On opening the existing switch I  was a bit confused as the neutrals all terminate in a connector block, and I couldn't understand why there was a wire linking the two at the commons.

What do I need to do to wire in a second switch for the strip lights?

here is a photo of the existing set up: https://photos.app.goo.gl/6N7GNMwCMWsJngUy5

 

[Sharpend]

The commons will be joined together as they are the permanent live supply to each switch. A switch generally only switches the live core this is why the neutrals are all joined together. 

It is possible to add an additional switch with a three core and earth cable. 

 

[corax]

Ah ok, that's great. I understand about the neutrals and the commons makes sense in hindsight.

How would I wire in the three core and earth? Do I need to cut the existing lives to the led strips?

 

[FLICKER]

No need to touch anything at the lights bud. Run a 3 core + earth from your existing switch over to your new switch. Isolate the circuit and then connect your existing feed (the one with the link) into a 3 port wago. From this take a cable to the common of the pir switch and to L1 of the strip light switch. Put the switch wire for your strip lights into terminal L2. Ok we are half way there lol. Now all you have to do with your new 3 core cable is join common to common, L1 to L1, L2 to L2 and connect the earth. So at the existing switch you end up with 1 cable in common and 2 cables in L1 & L2. 

 

[Sharpend]

Still don’t know why you need a Wago though, can’t say I’ve ever needed one on the thousands of two way I’ve done? 

You’ll just end up with three cables in L1? 

 

[FLICKER]

Still don’t know why you need a Wago though, can’t say I’ve ever needed one on the thousands of two way I’ve done? 

You’ll just end up with three cables in L1? 

That’s just me bud. I don’t like 3 cables in the same terminal on a switch, but yes you could have the 3 in L1 if that’s what floats your boat

 

[Sharpend]

Well you could always wire it differently to spread the number of cables in terminals? 

 

[FLICKER]

Yes you could do that bud. I was trying to make it as understandable as possible for Corax in a written explanation without knowing what side of the switch actually had the link in it. 

 

[Doc Hudson]

No need to touch anything at the lights bud. Run a 3 core + earth from your existing switch over to your new switch. Isolate the circuit and then connect your existing feed (the one with the link) into a 3 port wago. From this take a cable to the common of the pir switch and to L1 of the strip light switch. Put the switch wire for your strip lights into terminal L2. Ok we are half way there lol. Now all you have to do with your new 3 core cable is join common to common, L1 to L1, L2 to L2 and connect the earth. So at the existing switch you end up with 1 cable in common and 2 cables in L1 & L2. 

Not forgetting to allow for different makes of switch where some may be;  L1,L2,L3  and another C,L1,L2.  This is often an area of total confusion and mayhem for a DIY'er as;   C = L1,  L1 = L2  and  L2 = L3.   

Doc H.

 

[FLICKER]

Not forgetting to allow for different makes of switch where some may be;  L1,L2,L3  and another C,L1,L2.  This is often an area of total confusion and mayhem for a DIY'er as;   C = L1,  L1 = L2  and  L2 = L3.   

Doc H.

Good point bud. 

 

[Doc Hudson]

Good point bud. 

Generally worse when the two switches are not the same designations. Or swapping out one type for the other. Poor old DIY bob just copies, 'L1' to 'L1', 'L2' to 'L2' and just guesses that 'L3' must go to 'C'.

Doc H. 

 

[corax]

OK that's all great information - thanks everyone. I definitely have a solution now that even I'll be able to do!

 

[corax]

Ive got this working now which is great. Thanks for the help. One other question though, I now have 4 earth cables in this switch box, could I terminate them all in a wago, it's a bit of a fiddle to get all 4 in the earth block!

 

[roys]

Yes put them into a 4 or 5 way Wago, don’t forget to sleeve your earth wire.

 

[Sharpend]

Are these switches plastic or metal? 

If plastic it’s ok to put into a wago, if metal then you’ll need to put a fly lead into the switch earth point. The back box if metal will also need an earth, so you may not need a wago at all if you put the earths into the back box earth point and a fly lead over to switch.