Timer light switch

[Pocster]

Hey all,

 

I have a hallway where I have a switch at the base of the stairs and a switch at the top that turn on jointly lights top and bottom of stairs.

They were the push mechanical ones which are now busted.

I bought a cheap (eBay!!!) one for the top stairs that seems to work (bit flakey).

The down stairs switch is dual gang (is that the correct terminology?) anyone recommend a non mechanical switch that would work here?

 

Cheers

 

 

[ProDave]

Regardless of the number of wires, only 2 terminals are in use, so that's just another single pole switch.

[Carrerahill]

Hang on, hold fire. I don't think this is as simple as replace with a normal switch. That is still known as a single gang switch, gangs in switches and sockets is how many independent circuits/sockets it has. 

 

I could do with a sketch here to show it but the circuit you have is a parallel switch arrangement. Typically used in corridors and stairs where pneumatic switches like the ones you had were fitted or now sensors. It is almost certainly not a two way switching arrangement. The way it works is that each switch simply closes the circuit at one end, light comes on, if you then hit the switch upstairs it closes it there too and the light comes on. When the switch(s) release there is open circuit in both areas and your light goes off.

 

If you were to put a normal switch here you would loose the ability to switch off from upstairs, once the switch at the bottom is on, regardless of what the other switch does it would be on - you would need to go back downstairs and switch it off. 

 

Very difficult to know looking at 1 picture with 4 wires - but one of the red wires into Com will be the live feed, the second red wire in Com will run to the second switch. On the other terminal you have red and black wire, one of them, probably the black will be the return from the other switch so would I be right in saying it only has a red and black wire going into it? The red in with the black will then go to the light. It looks like there is a neutral connection in the back box, that will be the feed direct to the light.

 

This means you probably only have 2 wires between the switches... so 2-way switching arrangements will not be possible. 

 

However, just in case:

 

If live and neutral exist in the same box and run out then you will need 3 wires between the switches. If however, live starts at one end and goes to a switched output at the opposite and neutral is at the rose then you MIGHT get away with 2 wires between the switches but from what I can spy I think not.

 

Best best, another pneumatic switch or a PIR face-plate assuming you do have a neutral.

 

 

 

 

 

 

 

 

[Nickfromwales]

9 minutes ago, Carrerahill said:

Hang on, hold fire.

Indeed lol. 

4 wires? Are we sure this isn't an old intermediate switch location that's been converted to run the percussion delay switches?

Firstly  we need to know how many more switches control these lights. 

If its 3 ( 2x landing 1x hall etc ) then we need to see inside those to, to ascertain what were dealing with BEFORE assuming anything. 

As alwsys, WITH THE POWER TURNED OFF . 

This is old wiring, older than the delay switches for sure, so let's see what's lurking before leaping. 

[Carrerahill]

20 minutes ago, Nickfromwales said:

Indeed lol. 

4 wires? Are we sure this isn't an old intermediate switch location that's been converted to run the percussion delay switches?

Firstly  we need to know how many more switches control these lights. 

If its 3 ( 2x landing 1x hall etc ) then we need to see inside those to, to ascertain what were dealing with BEFORE assuming anything. 

As alwsys, WITH THE POWER TURNED OFF . 

This is old wiring, older than the delay switches for sure, so let's see what's lurking before leaping. 

He does say he has a switch at the base and a switch at the top which made me write what I wrote - lets see what he says - if he forgot to mention a 3rd location then we can go back to the drawing board.

 

However, if it was an int. switch circuit then the pneumatic switch wouldn't work the circuit properly because the wires have been combined so all three switches would need to be on for light. If it was in a combination with a 2 way switch it would also not work as the pneumatic switch would need to be on for anything to happen and regardless of switch position the lights would be on as the 2 way switch wires are combined.

[Pocster]

Hey guys 

 

thanks for the help ; now I am confused !

there are only 2 switches and 2 lights . Either switch turns on both lights .

the upstairs light switch was the same mechanical type but just 2 brown (live) wires . I replaced that with a 1 pole timer touch switch which seems to work I.e turns on both lights .

so the downstairs one as in the photo is the issue . I *guess* if I bought the exact same mechanical switch I'd be ok ; though still not finding what I need online . A direct replacement makes this easy ; yeah ??

 

cheers

[Pocster]

Oops !

shoujd also mention ( may not be relevant ) there is battery backup emergency lighting . So when I flip the ' stairwell lighting ' trip off emergency lighting kicks in .

 

cheers

[Carrerahill]

30 minutes ago, pocster said:

Hey guys 

 

thanks for the help ; now I am confused !

there are only 2 switches and 2 lights . Either switch turns on both lights .

the upstairs light switch was the same mechanical type but just 2 brown (live) wires . I replaced that with a 1 pole timer touch switch which seems to work I.e turns on both lights .

so the downstairs one as in the photo is the issue . I *guess* if I bought the exact same mechanical switch I'd be ok ; though still not finding what I need online . A direct replacement makes this easy ; yeah ??

 

cheers

The emergency lighting is fine, we can essentially ignore it, it will have a live feed direct from the lighting circuit which is its permanent live to charge the batteries, there should be a little charge indicator LED. Just out of a matter of interest why do you have EM lighting in your home? It is very rare to see it in a domestic situation.

 

So, you have a parallel switched circuit then. So look at my original reply regarding how it works and look at the attached image, basically if you imagine a piece of wire sitting horizontally in front of you, this is the live. Then imagine sitting below it horizontally another piece of wire, this is the connection to the light.

 

Now if you want to switch it on you need to continue the circuit between the two, so you get another piece of wire and lay it across the two horizontal wires to bridge them - the power can flow from top wire to bottom wire and the circuit it closed. Now take another piece of wire and drop it across the two horizontal wires, nothing will happen, it just means there are two paths for electrons to flow. Now if you lift the first piece of bridge wire you put down the light will remain on unless someone lifts the second piece - your pneumatic switches work exactly the same way. 

 

The reason you have 2 wires at each terminal of the the switch is because that is the wire going on to the second switch to create your long horizontal wire in our explanation above. Look at the bottom diagram and you will see the red lives comes along, but another red live goes to the bottom switch. The white is the black in your case which goes back to the other side of the first switch it is paired up with a red which goes to the lights. 

 

Any pneumatic switch will work: http://www.screwfix.com/p/elkay-columbus-pneumatic-time-delay-switch/68088?kpid=68088&gclid=CM_gmKrnxNMCFQ0R0wodVGIE6A&gclsrc=aw.ds&dclid=CPTdp6rnxNMCFawB0wodjgYC-w

 

Edited April 27, 2017 by Carrerahill

[Pocster]

3 minutes ago, Carrerahill said:

The emergency lighting is fine, we can essentially ignore it, it will have a feed from the lighting circuit direct in as a permanent live to charge the batteries there should be a little charge indicator LED. Just out of a matter of interest why do you have EM lighting in your home? It is very rare to see it in a domestic situation.

 

You have a parallel switched circuit then. So look at my original reply regarding how it works and look at the attached image, basically if you imagine a piece of wire sitting horizontally in front of you, this is the live. Then imagine sitting below it horizontally another, this is the connection to the light.

 

Now if you want to switch it on you need a circuit between the two, so you get another piece of wire and lay it across the two horizontal wires - the power can flow from top wire to bottom wire and the circuit it closed. Now take another piece of wire and drop it across the two horizontal wires, nothing will happen, it just means there are two paths for electrons to flow. Now if you lift the first piece of wire you put down the light will remain on unless someone lifts the second piece - your pneumatic switches work exactly the same way. 

 

The reason you have 2 wires at the switch is because that is the wire going on to the second switch to create your long horizontal wire in our explanation above. Look at the bottom diagram and you will see the red lives comes along, but another red live goes to the bottom switch. The white is the black in your case which goes back to the other side of the first switch it is paired up with a red which goes to the lights. 

 

 

 

 

 

 

 

Brilliant explanation thank you !

the stairwell is the entrance way to 2 flats ; ground and first floor .

so do I purchase a normal pneumatic switch ?  - nothing special just bog standard ??

 

cheers again 

[Carrerahill]

3 minutes ago, pocster said:

Brilliant explanation thank you !

the stairwell is the entrance way to 2 flats ; ground and first floor .

so do I purchase a normal pneumatic switch ?  - nothing special just bog standard ??

 

cheers again 

Yes, they will all just have terminals for in and out - see edit in post above - I added a link.

 

Normally I would suggest if you are not sure to seek pro help, but to be honest it's a very simple 2 wires one side, 2 wires the other side connection. 

Edited April 27, 2017 by Carrerahill

[Pocster]

Thanks ! Very helpful ! - all of you !

will order one up ! ?