2 gang 2 way switches

[robbie77]

Hi

I am wanting to install 2x 2way 2gang light switches(both lights can be operated from either side of the room).

Am I right in thinking that I am going to need 2x lengths of 3 core from each switch?
I have looked at the wiki at 2 way switching so I am assuming that the one switch plate is to be seen as 2 different switches?

Need to get my theory sorted!
Thanks

 

[electronicsuk]

Your assumption is correct. In addition to a pair of 3C+E between the switches, one switch plate will also need to have the switch drops run to it, assuming you have loop in/out at ceiling rose.

 

[robbie77]

Your assumption is correct. In addition to a pair of 3C+E between the switches, one switch plate will also need to have the switch drops run to it, assuming you have loop in/out at ceiling rose.

Thanks..

It's an old house with junction boxes for most of it I think.
Does that mean from one light will have three wires from it, the 2 3C+E and one to the light (normal 1.5 t&E)?

 

[electronicsuk]

Thanks..

It's an old house with junction boxes for most of it I think.
Does that mean from one light will have three wires from it, the 2 3C+E and one to the light (normal 1.5 t&E)?

Nope. Assuming you really do mean light, and not switch.

The pair of 3C+E cables only need to link between the two switches. For each gang, link L1 on the near switch to L1 on the remote, L2 to L2, and Com to Com. Your switch drop wires (probably twin+earth on the existing switches) should then go in L1 and L2 at one of the switch plates, although it makes no difference which one.

Hope that makes sense!

 

[robbie77]

Thanks..

It's an old house with junction boxes for most of it I think.
Does that mean from one light will have three wires from it, the 2 3C+E and one to the light (normal 1.5 t&E)?

Nope. Assuming you really do mean light, and not switch.

The pair of 3C+E cables only need to link between the two switches. For each gang, link L1 on the near switch to L1 on the remote, L2 to L2, and Com to Com. Your switch drop wires (probably twin+earth on the existing switches) should then go in L1 and L2 at one of the switch plates, although it makes no difference which one.

Hope that makes sense!

Not really.... If I have two lengths of 3C+E cable, one from one switch and one to another what am I going to use as a switch drop? Or is one light switch connected to another using the 3C+E cable and the 3C+E cable goes to the the/ one of the lights?
It's me being thick sorry..

 

[electronicsuk]

Not really.... If I have two lengths of 3C+E cable, one from one switch and one to another what am I going to use as a switch drop? Or is one light switch connected to another using the 3C+E cable and the 3C+E cable goes to the the/ one of the lights?
It's me being thick sorry..

As each switch is 2 gang, you will need two lengths of 3C+E between the switch plates, one per gang. As you appear to have some form of loop in/out at ceiling rose/J.B. wiring method, you will then need 2x lengths of T+E from the ceiling rose/J.B. down to ONE of the 2 gang switch plates. Again, one length of T+E per gang, and these are the switch drops.

This means that one switch plate will have 2x 3C+E cables entering it, the other will have the opposite end of those two 3C+E cables plus another pair of T+E.

If you wanted, you could substitute the pair of twin + earth cables for an additional 3C+E and share the permanent live between the two gangs, but it will require a common junction box for both lights, and that they both be on the same circuit. If it's for a landing light then this may not be possible/practical.

EDIT: Just to clarify, although difficult to explain in words (no doubt there are pictures in the WIKI), there really is nothing difficult about 2-way lighting circuits. The switch drops are completely standard even on a single way circuit, all you're doing is adding additional lengths of 3C+E and extra switches.

 

[robbie77]

Thanks for the clear explanation and the patience Mathew


I think I've got it. The 2 lengths of T&E are the switch drops from each light which wire into each respective switch!?

 

[electronicsuk]

Thanks for the clear explanation and the patience Mathew


I think I've got it. The 2 lengths of T&E are the switch drops from each light which wire into each respective switch!?

Correct. The switch drops are exactly the same as they would be on single way switching. Two gang, to switch drops. The only difference here is the additional pair of 3C+E from the first switch to the extra 2-gang switch plate, but that doesn't affect the wiring at the light itself, only the switch.

 

[ban-all-sheds]

//www.diynot.com/wiki/electrics:lighting

 

[robbie77]

//www.diynot.com/wiki/electrics:lighting

I have looked at the wiki at 2 way switching

It's me being thick sorry..

Another inspiring post ban-all-sheds.......

Maybe people need a little more explaining than others. We can't all be perfect !

 

[ban-all-sheds]

OK - given this initial exchange

I have looked at the wiki at 2 way switching so I am assuming that the one switch plate is to be seen as 2 different switches?

Your assumption is correct. In addition to a pair of 3C+E between the switches, one switch plate will also need to have the switch drops run to it, assuming you have loop in/out at ceiling rose.

if you then have to ask a question llike this:

If I have two lengths of 3C+E cable, one from one switch and one to another what am I going to use as a switch drop? Or is one light switch connected to another using the 3C+E cable and the 3C+E cable goes to the the/ one of the lights?
It's me being thick sorry..

having seen this drawing

which really could not be a clearer answer to your question then it isn't more explaining you need. I genuinely cannot see how you have looked at the Wiki properly.

Just what is it about that drawing which does not, with complete clarity, answer the question you asked?

If you really have studied it, and all of the others, e.g. this one:

and you really cannot see where the switch drop goes and where the 3C+E goes then maybe you were right:

It's me being thick sorry..

and maybe you need to realise that you are too thick to do electrical work.

 

[SUNRAY]

maybe you need to realise that you are too thick to do electrical work.

I can honestly say that on far too many occassions on this site I would like to make this comment

 

[ban-all-sheds]

It's not a judgement I reach very often - I used the term here because it was the OP's verdict on himself.

Is he actually thick? Probably not - more likely he's simply one of those people for whom electrics just doesn't click.

 

[robbie77]

Another inspiring post ban-all-sheds....... icon_rolleyes.gif

Maybe people need a little more explaining than others. We can't all be perfect !

 

[ban-all-sheds]

The point I'm trying to make Robbie is that if you can look at a perfectly clear drawing of two switches linked by 3C+E, with one of the switches having a twin & earth cable dropping down from the light, and been told in writing that your drop cables will be twin & earth still think that maybe the way to wire it is with "one light switch connected to another using the 3C+E cable and the 3C+E cable goes to the the/ one of the lights" then for whatever reason you just cannot get your head around electrical stuff, and therefore you should leave it alone.

Something this simple should not be a struggle . Something this simple should not need more explaining than those drawings provide. Something this simple should be "oh yeah - I see exactly how that hangs together, no problem".

I do not see it as this site's role to "inspire" you to do work on something you clearly cannot understand.