UK Replacing standard switch to smart switch

AaronP · Sep 4, 2021

Hi,

I am looking to replace my bathroom switch in my flat for a smart switch.
The switch controls 4 downlighting and the extractor fan. The extractor is also controlled from a separate switch in the kitchen. I.e two ways

below is picture of the old switch wired up.
Supply side has 3 brown lives in L and another brown in N
Load side has a switched neutral in the N and another brown in the L
The rest of the neutrals and in an block in the back box.

The new switch has only 1 neutral, an L and a L1.

I cannot for the life of me figure it out.
Am I stupid or Will this new switch not work?

any help is massively appreciated. Thanks Aaron.

[ElectriciansForums.net] Replacing standard switch to smart switch

littlespark · Sep 4, 2021

The terminals marked N are not neutrals.. Its just a double pole switch.
The blue is sleeved in brown to indicate a switched live.

AaronP · Sep 4, 2021

littlespark said:
The terminals marked N are not neutrals.. Its just a double pole switch.
The blue is sleeved in brown to indicate a switched live.

Thanks for the reply, so Basically I need a double pole switch to replace it with?

littlespark · Sep 4, 2021

Im not understanding how your extractor fan works. If it was two-way, ie can be operated from either switch, there would be 3 cables coming from the switch just for the fan.
Do both switches (kitchen and bathroom) need to be on for the fan to work?

You may not get a double pole smart switch... but you could get a 2 gang. So each switch on that plate can be turned on individually. Light on or fan on, or both, depending how you program it

telectrix · Sep 4, 2021

as above. the neutrals are the blues in the choc block, not connected to the switch itself.

AaronP · Sep 4, 2021

littlespark said:
Im not understanding how your extractor fan works. If it was two-way, ie can be operated from either switch, there would be 3 cables coming from the switch just for the fan.
Do both switches (kitchen and bathroom) need to be on for the fan to work?

You may not get a double pole smart switch... but you could get a 2 gang. So each switch on that plate can be turned on individually. Light on or fan on, or both, depending how you program it

Yeah that’s what confusing me aswell.
Nope either switch can be on for it to work.

It’s a new build and I’ve noticed a lot of the wiring seems to be a bit unconventional…

That’s a good idea though, just get 2 gang version instead.

Avo Mk8 · Sep 4, 2021

AaronP said:
Nope either switch can be on for it to work.

That could be the case with two single way switches in parallel (bathroom and kitchen). Either can turn it on, but both need to be off for the fan to be off. Is that the case here?
It doesn't look like a two-way switch to me.

2-gang smart switches typically have a common live in, and give a switched live out for each gang from that common source.
Here we have a two gang switch, presumably for a reason (?) so need to be sure there's not two seperate circuits in play. Basically, for the 2 gang smart switch option to work, you need to be sure both the lighting and fan are, or can be, fed from the same circuit, ie from a common live.