2 light switch setup

[jks7492]

Moved into a new house and we have 2 switches in the dining room (one near each door at opposite ends of the room).

They don’t operate as id expect with 2 way switching where both switches can turn the light on and off.
One of the switches seems to act as a ‘master switch’ and has to be left in the on position for the other switch to work. If it’s turned off then the light can’t be switched back on with the other switch.

Have the switches been wired incorrectly or is this just how they should operate?

 

[ericmark]

Not counting earths I would expect 5 wires on master switch and 3 wires on slave, I can only see 4 on the master switch.

Also would only expect one wire in com on both switches, but I see two on the master.

However there are many ways to wire two way switches, in the main it needs three wires between the two switches, but I have seen a pair of dimming two way where only 2 between master and slave.

There are also kinetic switches which will work without wires between them. And smart switches which have battery in slave switches (remote controls) even with some batteries in the master, so it does not need a load, handy when switching outside lights with PIR.

But you will need some thing to test with, so what have you got?

 

[Taylortwocities]

Yes, I agree. Two reds in the COM doesn’t look right.
Needs some detective work, unlikely to be fixed via an Internet forum, IMO.

 

[blup]

Difficult to make out what goes where. If it's the conventional set up, identify which cable goes to the lamp holder, and put live in L2 and switched live/neutral in L1. For the strapper, which is three core and earth, the live goes in COM at the first switch, with each switched live at L1 and L2, making sure the other ends are in the same respective terminals, with the live in COM

 

[Taylortwocities]

It’s old wiring @blup. No 3-core and earth to be seen.

 

[EFLImpudence]

and switched live/neutral in L1.

Best not do that.

 

[SUNRAY]

It’s old wiring @blup. No 3-core and earth to be seen.

Ohh these youngsters

From what I see it is potentionally wired conventional 2 way:

Which should be quite straightforward to faultfind

However before offering any advice I'd like to know if there are any other wires at the switches and is there any test equipment available?

 

[jks7492]

Ohh these youngsters

From what I see it is potentionally wired conventional 2 way:
View attachment 329203Which should be quite straightforward to faultfind

However before offering any advice I'd like to know if there are any other wires at the switches and is there any test equipment available?

No other wires at the boxes other than what’s already connected to the switches in the photos.

A multimeter and an electric screwdriver…

 

[fixesthingssometimes]

I suspect in the second picture swapping red and the top right sleeved wire might fix it.

If its what Sunray said which is plausible, then in the second picture the red and the bottom right sleeved wire would be the travellers.

The way it is wired now, the master switch (assuming the left photo?) would liven up one of the travellers. The only way to make the light go on is for the red traveller to be live, and then the second switch to connect that red wire to the top right sleeved wire.

If you only have a multimeter, switch everything off and then confirm that the L1/L2 on the first switch are connected to the red and bottom right wire on the second photo. Simply disconnect the wires both ends, confirm with a resistance check from one end that there's no connection, then short the other end with a wago/terminal block/whatever, and then that the resistance is low. If that holds, try the experiment I said.

 

[blup]

Best not do that.

Alternative names, not two wires

 

[EFLImpudence]

Alternative names, not two wires

What?

You think 'switched live' and 'neutral' are just alternative names for the same wire?

and put live in L2 and switched live/neutral in L1.

 

[blup]

What?

You think 'switched live' and 'neutral' are just alternative names for the same wire?

Yep it’s coloured neutral and becomes switched live when sleeved and fitted. You have to remember the OP may not be not au fait with all the terms

 

[ericmark]

Ohh these youngsters

From what I see it is potentionally wired conventional 2 way:
View attachment 329203Which should be quite straightforward to faultfind

However before offering any advice I'd like to know if there are any other wires at the switches and is there any test equipment available?

There still needs to be in the main three core and earth, I know

is the more normal way as no block connector required in the lamp, but if switch back box used as the junction box instead of the ceiling rose, then there would also be neutrals in the back box.

I do agree however some test equipment is required to fault find.

 

[SUNRAY]

Yep it’s coloured neutral and becomes switched live when sleeved and fitted. You have to remember the OP may not be not au fait with all the terms

So it be better to not confuse OP with incorrect information.

Just to clarify NEUTRAL and SWITCHED LIVE are NEVER the same thing and can only change if an existing cable is reused for a different purpose.

The colour of the wire is BLACK and NOT neutral.

 

[SUNRAY]

View attachment 329261There still needs to be in the main three core and earth, I know View attachment 329262 is the more normal way as no block connector required in the lamp, but if switch back box used as the junction box instead of the ceiling rose, then there would also be neutrals in the back box.

I do agree however some test equipment is required to fault find.

In many (probably most) 2 way systems of yesteryear there would only be 2 strapper between switches and typically a red/black twin(and earth?)
In the left picture I think I see a varilite dimmer, 2* T&E but only one black from them and a single sheathed black, at the right switch I think I see one red and 2 blacks sleeved brown. I'd like confirmation and more detail of those ideally by pictures showing the cable sheathes or a good description of them at both switches. before I can answer further.

Thinking further I'm wondering if it's all wired in single&E sheathed cables

Oh silly me, this appears to be a dimmer, does the dimmer work?