Two way lighting, two wires?

[phonebook]

Hi , I have just taken off an old double light switch, replacing with new , and yes wires do no match the new c L1 L2 c L1 L2config.

Downstairs hallway.

Has the 2 gang switch.it has two grey sheathed cables cable 1 and cable 2.One is for a one way switch to hall light using cable 1.
Red common, black to L2, and earth to casing buttress.(this works fine)

The second switch,on the same gang, has to be two way going upstairs to the landing single switch .Cable 2 , entering the two way switch downstairs,has red , black and earth the switch only appears to be red, black and earth.

Upstairs single switch, has red black and earth also.

Could you advise on how to wire the switches please , previous postings show different situations as I understand them .

Many thanks

 

[Lectrician]

take a look at the other topics, particularly the landing one a couple lines down. This should sort you.

 

[BigHammo]

How many coloured cables do you have in the switch upstairs? Is it three? If so you must have junction box under the floor boards.

And did you say that the hall light, and down stairs light are on the same gang? If so when you turn the upstairs switch of does the hall light stay on?

If they are not on the same gang is there a small piece of cable that runs from the hall switch (1st gang) to the 2nd gang switch (upstairs switch, must be the Common).

What I suspect is that the live from the hall light connects to the common, and the l1 & l2 connect to l1 & l2 on the upstairs switch. The common on the upstairs switch should then have a cable going to the light.

This is an alternative way of wiring switches, although not todays practice. I have tried show this below.

l1_________________l1
live________C C____________light

l2_________________l2

 

[BigHammo]

How many coloured cables do you have in the switch upstairs? Is it three? If so you must have junction box under the floor boards.

And did you say that the hall light, and down stairs light are on the same gang? If so when you turn the upstairs switch of does the hall light stay on?

If they are not on the same gang is there a small piece of cable that runs from the hall switch (1st gang) to the 2nd gang switch (upstairs switch, must be the Common).

What I suspect is that the live from the hall light connects to the common, and the l1 & l2 connect to l1 & l2 on the upstairs switch. The common on the upstairs switch should then have a cable going to the light.

This is an alternative way of wiring switches, although not todays practice.

 

[phonebook]

The link below was great but, the diagram showing the upstairs light switch ,confues me.It shows red and black from downstairs plus a further red? I only have a single red/black and earth entering the switch. or am I reading it wrong?

//www.diynot.com/forums/viewtopic.php?t=13213

 

[Lectrician]

Is the upstairs switch deffinantly for operating the landing light 2 way?? Did it always work?? A third core is needed for 2 way operation.

 

[phonebook]

Ok, my notes on the switches wire was wrong upstairs.. Yes the upstairs two way single switch has its own sheathed red wire, together with , red black and earth.

I have wire it according to the diagram instructions... and now I get is the landing light working, only one way(instead of two way) from downstairs, and the downstairs light on the one way not working at all.

Any suggestions?

 

[MANDATE]

I think your two way system is a old version. This has a 'live' wire going to 'com' on switch No 1. Followed by two wires linking switch No 1 to switch No 2. ie L1 to L1 and L2 to L2. Followed by a 'switched live' wire from 'com' on switch No 2 to the ceiling rose.
You appear to have the 3 wires at switch No 2 but you only mention two wires at switch No 1.
What has probablely happened is there would be no point in providing a separate live wire to the 'com' terminal when there is already one going to the adjacent switch which is operating in a one way mode. All that is needed is a short wire to link 'com' to 'com'.which provides the required live
I suspect there was a link there which was not noticed when it was dismantled.
I think your red and black wires link the switches, the second red upstairs goes to celing rose. Downstairs the other red goes to 'com' with a link to the adjacent 'com' and the black goes to L1 (or L2 if you wish)