2-gang light switch - how to make one circuit switch on the other?

[john2k]

I have a 2-gang light switch on one plate, each gang controlling a separate lighting circuit:

1. Downlights
2. Ambient LEDs

Both circuits are separate, but I want it so that:

Ambient lights can be switched on by themselves
When I turn ON the downlights, the ambient circuit also turns ON if it isn’t already turned on.

What’s the correct way to achieve this?

 

[ETAF]

picture of the inside of the switch wiring - it maybe as simple as just adding a loop in the switch

do you have a multimeter and know how to use it - so you can identify the switch live and the live

the switch may already be using a common live for both lights

 

[SUNRAY]

Picture of the back of the switch showing wiring please

 

[SUNRAY]

Picture of the back of the switch showing wiring please

 

[SUNRAY]

Picture of the back of the switch showing wiring please

EDIT: Apologies forthe multiple posts, the site didn't appear to be working and ETAFs reply wasn't showing when I tried 3 times

 

[john2k]

picture of the inside of the switch wiring - it maybe as simple as just adding a loop in the switch

do you have a multimeter and know how to use it - so you can identify the switch live and the live

the switch may already be using a common live for both lights

I will try and get a picture later this evening. it's quite hard to picture as it's a very tight location but will try otherwise will try and draw the layout. I do have a multi-meter and know how to use it yes. Both of the light circuits are using the same live but they just have two different switched outputs

Picture of the back of the switch showing wiring please

EDIT: Apologies forthe multiple posts, the site didn't appear to be working and ETAFs reply wasn't showing when I tried 3 times

As above, will try and take a photo of it this evening.

 

[ericmark]

Looking at IFTTT, or if this then that, many smart switches allow the use of IFTTT, but hard-wired, it would need a relay, or use of DC, had the same problem with central heating, with one boiler serving both main house and flat, and stopping back feeds.

 

[john2k]

picture of the inside of the switch wiring - it maybe as simple as just adding a loop in the switch

do you have a multimeter and know how to use it - so you can identify the switch live and the live

the switch may already be using a common live for both lights

I’ve thought through the looping idea but I don’t think a simple loop will work for what I need.

The wiring is currently as follows on one plate:

• Permanent live into COM of the downlight switch
• COM of downlight switch looped to COM of ambient switch
• L1 of downlight switch to downlights
• L1 of ambient switch to ambient lights

If I also loop L1 to L1, then turning on the ambient switch would back-feed the downlight circuit and turn the downlights on, which I don’t want.

What I need is:

• Ambient can be switched on by itself
• When downlights are switched on, ambient is forced on
• Ambient switch must not be able to power the downlights

 

[EFLImpudence]

Just to point out:

"2-gang light switch - how to make one circuit switch on the other?"​

Both of the light circuits are using the same live but they just have two different switched outputs

That means they are both on the same circuit.

 

[ETAF]

i had started to answer , asking if 2 way switches as well - so an L2 with an actual screw connection , but i see @EFLImpudence has provided the drawing i was making for you

so long as 2 way switches

 

[john2k]

what about using a AC relay and putting the relay into a enclosure. something like below maybe

 

[john2k]

Just to point out:

"2-gang light switch - how to make one circuit switch on the other?"​

That means they are both on the same circuit.







View attachment 403731

I think I understand the diagram. This is what it does in practice:

• Ambient switch ON → Ambient and downlights come ON
• Downlight switch ON → Downlights and ambient come ON ✔
• Either switch OFF → Both go OFF

So it effectively makes both switches control the same combined circuit.

What I need instead is:

• Ambient ON by itself
• Downlights ON forces ambient ON
• Ambient ON must not turn downlights ON

 

[ETAF]

• Ambient ON by itself

which is how the diagram is drawn by

@EFLImpudence​

as far as i can see - both switches in ON position

- only ambient lights will be on​

if ambient lights switch to off and downligts OFF - then they will both will be off - providing the downlight switch is OFF
if the downlight switch is ON , then ambient lights are on

i think it works as you want

if downlight is switch is ON (downlight will be ON & the ambient lights will be ON), no matter if the ambient switch is ON or OFF ambient will be ON
if downlight is OFF (downlights will be OFF) , then the ambient switch will either switch OFF or ON the ambient lights

as mentioned a few posts ago post No 10 - you need 2 way switches - which you most likely have - BUT need to confirm they are not 2 gang single way

 

[endecotp]

I have a 2-gang light switch on one plate, each gang controlling a separate lighting circuit:

Stop saying “circuit”, it doesn’t mean what you think it means and it is confusing some of the other replies.

 

[endecotp]

I think I understand the diagram.

No, you don’t.

EFLI’s diagram does exactly what you want.