Fitting a timer switch to a 2-way circuit

[TR1CKY]

Hi Guys and Girls,

I'm not sure if anyone can help me but I've brought a 7 day electronic wall switch / timer with the intention of using it in place of the landing light switch upstairs.

Background;

You can switch the upstairs landing light on from downstairs, which is on a three switch arrangement (upstairs landing | hall | porch).

Into the downstairs landing switch it goes

Red - Common
Blue - L2
Yellow - L1

Upstairs, the single switch it goes

Black - Common
Blue - L1
Yellow - L2
x2 Red live wires separated out into a connection block.

Now, the instructions for a typical two way circuit (5 wires one end 3 the other) say;

Connect live wire to LIVE
Com from other switch to LOAD
L1 from other switch to 2 WAY
Switched LIVE wire to LOAD
L2 on the other switch has no connection and must be isolated by connection block etc.

On the rear of the timer there are three options, 2WAY, LOAD, LIVE.
I went with;

Two RED LIVE into LIVE
Black (com) into LOAD
Yellow into block
Blue into 2WAY

Needless to say, the reason I am here is that I can't get it working. I have managed to get it so that the upstairs single switch turns the landing light on and off, but can't get the downstairs hallway one to operate the landing light at all.

Any ideas please?

Thanks!

 

[SaladFingers]

What's the make and model?

Is it a Timeguard?

 

[TR1CKY]

It's a bog standard B&Q one - not branded.

 

[EFLImpudence]

Are you using compact fluorescent lamps?

Some timers won't work with these.

 

[TR1CKY]

No, they are standard 40w bulbs.

 

[EFLImpudence]

Two RED LIVE into LIVE
Black (com) into LOAD
Yellow into block
Blue into 2WAY

What do you mean by yellow into 'block'?

 

[ban-all-sheds]

OOI - what's supposed to happen when the timer turns the light on?

Can it still be turned off from the downstairs switch?

Anyway....

Now, the instructions for a typical two way circuit (5 wires one end 3 the other) say;

But you don't have a typical 2-way circuit. You may have 5 wires at one end, but only 3 of them are connected to the switch, and your switched live is in COM, not L1 or L2.

Draw it out and see how it works - you need to understand what's going on.

Com from other switch to LOAD

Compare what's connected to your COM with what would be connected in a typical 2-way circuit.

Two RED LIVE into LIVE

Which is not what the instructions say, is it. They don't tell you to put 2 wires into LIVE.

Black (com) into LOAD

But the instructions also tell you to put the COM from the other switch into LOAD, and you haven't done that.

As I said - draw it out.

You will be able to make it work with the wiring you have, and without changing the connections at the downstairs switch, but you will have to either change, or imagine changing, what's connected, or would be connected, at the landing switch (the original, not the timer). You need to end up with all 5 wires in the landing switch, or knowing where they would be in the landing switch in a typical 2-way circuit, i.e. the bottom left one of the first set of schematics here: //www.diynot.com/wiki/electrics:two-way-lighting

 

[TR1CKY]

What do you mean by yellow into 'block'?

As in "L2 on the other switch has no connection and must be isolated by connection block"

So I put the L2 (yellow) from the other switch into a connection block.

OOI - what's supposed to happen when the timer turns the light on?

Can it still be turned off from the downstairs switch?

Dunno! Good question. In theory though the house will be empty as you'd only use the timer when you're going on holiday etc. Well, I would anyway...if I ever get it working, I'll let you know!

I wouldn't have thought that I'd have to do anything with the downstairs switch?

There is another "Typical two way circuit (3 wires both ends)" section on the instructions.

Live wire to LIVE terminal
COM from the other switch to LOAD terminal
L1 from the other switch to 2WAY terminal
Switched LIVE to the other switch COM terminal
L2 must be separated into block

Does this make sense for my scenario?

 

[EFLImpudence]

As in "L2 on the other switch has no connection and must be isolated by connection block"

But the yellow is connected to it (or so you said and so it should be)

So I put the L2 (yellow) from the other switch into a connection block.

I am having trouble following your logic.

I wouldn't have thought that I'd have to do anything with the downstairs switch?

Better not.

There is another "Typical two way circuit (3 wires both ends)" section on the instructions.

Getting there.

Live wire to LIVE terminal
COM from the other switch to LOAD terminal
L1 from the other switch to 2WAY terminal
Switched LIVE to the other switch COM terminal
L2 must be separated into block

Not exactly.

You do have a three wire at each switch.
The confusing thing is that all of the wires start upstairs.

Would this help? -

Red..Common------------------------join----------
....................= Load....Black----------------------
Yellow........L1 = Live.....Yellow
Blue...........L2 = 2way...Blue

 

[EFLImpudence]

I would add that it could have been a five wire system upstairs with the old switch but I don't think the timer would work like that so you would have had to alter it.
I don't have any instructions.

Perhaps someone could confirm.

 

[ban-all-sheds]

I would add that it could have been a five wire system upstairs with the old switch but I don't think the timer would work like that so you would have had to alter it.

It could have been.

Right up until 2nd fix, it could have been.

But then whoever installed it decided to send the permanent live to COM in the downstairs switch in the red core of the 3C+E, wire the other 2 cores as L1 & L2 strappers, and take the switched live from COM in the upstairs switch.

I know not why. Ignorance, most likely.

 

[ban-all-sheds]

There is another "Typical two way circuit (3 wires both ends)" section on the instructions.

Live wire to LIVE terminal
.
.
.

I'd be a little dubious of that, because with that type of circuit you don't have a permanent live at both ends, yet the instructions seem not to recognise that.

But it doesn't matter - at the landing switch you have a switch drop cable and a 3-core & earth strapper running to the hall switch. Some numpty had it connected up in an odd way, but if you go back to first principles, look at how it would conventionally have been wired, and connect your timer according to the instructions but using the wires which would have been used in the conventional wiring then as long as the timer works as promised you'll be OK.

 

[ban-all-sheds]

As in "L2 on the other switch has no connection and must be isolated by connection block"

But the yellow is connected to it (or so you said and so it should be)

I think that means L2 in the remote switch ends up with no connection to the timer switch.

So I put the L2 (yellow) from the other switch into a connection block.

I am having trouble following your logic.

That's what the instructions say.

So if you regard the remote switch as a volt-free trigger to the electronics in the timer, you can see how it could work like that.

 

[TR1CKY]

So if you regard the remote switch as a volt-free trigger to the electronics in the timer, you can see how it could work like that.

Thank you B-A-S - drawing it out has made the penny drop. The logic above worked a treat and it's now fully operational which means a happy Mrs, which is priceless

When you have it on a timed "on" period, it seems to disable/override the 2 way element of the switch until it's "off" again.

Thanks again

 

[EFLImpudence]

Interesting.

So, I shouldn't speculate without the instructions.


However, I'm a bit puzzled why/how, in the OP, you wrote this - which is wrong - but is in fact the wiring for the timer which has now been done.

Now, the instructions for a typical two way circuit (5 wires one end 3 the other) say;

Connect live wire to LIVE
Com from other switch to LOAD
L1 from other switch to 2 WAY
Switched LIVE wire to LOAD
L2 on the other switch has no connection and must be isolated by connection block etc.