Why would a 1 way circuit share L1 with a two way circuit on 2 gang switch

[gingemonster]

I have a 2 gang 2 way light switch with:

• The left hand side part of a 2 way circuit with another switch
• the right hand side a 1 way circuit (this the only switch) switching two lighting circuits in parallel (a bathroom light and mirror light)

What I didn't expect is for there to be a bridge between the L1 of each switch. Its like L1 is being used for the permanent live maybe?

What am I missing?

thanks
Brian

 

[oldbutnotdead]

It's one way of wiring 2 way lighting circuits. If you sketch out the connections you'll see how it works (used to be some useful examples in the wiki but can't find them now)

 

[gingemonster]

@oldbutnotdead Im still confused if thats the case then, as I mentioned the switch on the right is NOT a 2 way switch (this is the only switch that turns the lights connected to it on), only the switch on the left is part of a two way (2 switches controlling the same circuit)?

 

[bernardgreen]

 

[gingemonster]

Thanks @bernardgreen thats the diagram I'm expected so does that mean my assumption is correct and that in that photo the permanent live is actually wired into the L1 terminal on both switches? Its that point that is confusing me I think

 

[bernardgreen]

Yes. your assumption appears to be correct. the permanent Live is connected to the L1 terminals

 

[gingemonster]

great thanks all I just wanted to make sure I wasnt going mad (well mader)

 

[EFLImpudence]

It has not been explained very well.
The light circuit is looped at the switches; i.e. the supply comes in on one cable and continues to the next switch on another.
These two obviously have to be connected and both of your switches need the supply, so rather than put both wires in one switch with a third wire to the other switch (three wires in one and one wire in the other), they are shared so that two wires are connected to each switch.

BUT you appear to have three wires in the L1 terminals.

 

[EFLImpudence]

Apart from that, both of your switches appear to be wired in the same way - that is both for two-way switching.

 

[gingemonster]

thanks, even weirder then as the switch on the right has no other switch anywhere that turns on the same lights so maybe it was intended to be that way but never completed or it just looks that way but the one of the right is controlling two separate lighting circuits (it turns the ceiling lights on and a light above the mirror) hence the doubling up of wires in each terminal?

 

[EFLImpudence]

Could we have another picture so that it is 100% clear where each wire goes?

 

[gingemonster]

Ill try and get one, with some many wires in the back box it's hard to get a clear shot

 

[gingemonster]

A photo is never going to make it clear so here is my attempt at sketching it, colours are to match my photo for my own sanity

Just a reminder Switch1 is the two way switch connect to a switch elsewhere, Switch2 is a single switch but controlling 2 lights

 

[SUNRAY]

That's slightly unusual the way cable 5 is wired, is this for a bathroom with an automatic fan?

 

[EFLImpudence]

I would think so -