Two way switching advise

[PaulNorris]

Hi

I've knocked two rooms into one and have a light switch either end which controls a single light. I want to wire up 2 way switching so I can turn each light on and off from each end of the room.

I've found various diagrams on how to do this, one way involves running a twin and earth between the two existing light switches and the other involves using a three core and earth. I'm confortable with how I do this and was going to use the two wire system (i.e. twin and earth between the switches) because I have plenty of twin and earth cable. However, I came across this article:

http://www.lightwiring.co.uk/two-way-switching-two-wire-control/

It mentions a lot of downside to using this approach. It says that you can create some kind of induction loop that can cause a problem with hearing aids (not good while granny is living with us). Is this something I need to worry about? would I be better off buying some three core and earth to do the job??

 

[bernardgreen]

You will note that there are three wires going to each switch. Therefore you will need to use one triple and earth cable or two twin and earth cables ( one core not used ) down to each switch.

Use the right materials chosen after the design.

 

[ban-all-sheds]

I would have thought that 3C+E would be less work, as you just have to run it between the existing switch location for a light and the new switch. If you use the 2-wire method you'll have to reroute the switched live for each light to come from the other switch. And unless you use conduit, that will mean either using T&E, or double-insulated cables.

So either

At each switch, retain existing drop cable, add 2 x 3C&E strappers, no changes at the lights.

or

At each switch, retain existing drop cable, add 1 x T&E for switched live for the other light, add 2 x T&E strappers, at each light obtain the switched live from a different switch, not the existing switch cable.

 

[securespark]

Yeah, the 3 core method seems easier, no?

Run a 3 core from the front room switch to the back and another from the back room switch to the front.

 

[ericmark]

The link you give is not the normal way to use two wire. If you look at standard wiring diagram.

You will note the line goes to both switches. This should be along the same route as the return wires to ensure a balanced circuit but what has been done many times is to borrow the second switches line from an adjacent switch which as with any two wire system can produce interference with radios, TV, phones and grans hearing aid.

There are radio control switches which save running cables but if running cables is not a problem I would even control each light independent with two x two way switches.

It is common to split lighting into two with 2/3 on one switch and 1/3 on other giving three levels of lighting.

 

[PaulNorris]

Cheers for the speedy responses everyone, very helpful

Using 2 x three core and earth between the two switches seems like the way to go.

Many thanks