converting two one way switches to two way switching

[neilw]

Hello,
I'm converting two rooms into one (knocking down a partition) which means there will be two switches and two lights.

What I want is to have just one light. i.e. convert to two way switches.

Is there a way of achieving this without rewiring the switches to use three core and earth. It's not a big deal, but it would be nice if there was a simple way as I'm sure people have never always used three core...

Thanks.

 

[flameport]

What have you currently got at the switches?

Two way switches have 3 terminals, so require 3 live wires at each switch. They don't have to be part of the same cable (a twin+earth and a single+earth would do) but you still need 3 live wires. There is no other way.

 

[spark1]

First We need to know what wiring you have at your switches at present....is it one T&E at each....is it multiples of singles etc. Then what type of wiring have you got at the lights ..is it Loop in or singles....
More info needed , but you are probably going to have to run additional wiring to the switches.

 

[sparkyspike]

I'm sure people have never always used three core...

True. Singles were sometimes used for the extra core, or otherwise they would be wired in with a feed to one switch and a switched feed at the other switch with two-core in between for the 2 way strappers. Neutrals would then be stolen from somewhere else or run in single core.

 

[ban-all-sheds]

There are different systems for 2-way switching - see the Wiki.

They will all require you to add extra cabling.

 

[bernardgreen]

There are two ways to achieve it without adding a third core down to the switches but I would not recommend either of them for a DIY and domestic situation as they involve relays and / or diodes. Rewire is the best option

 

[ban-all-sheds]

Yes - I was discounting electronic systems.

If that's required there are purpose made wireless switches available.

 

[neilw]

ok, thanks. At the minute it is wired using standard 2 core/earth loop-in system.

I rewired the whole house myself so it isn't a big deal but I thought I could have saved some time with some magic wiring techniques I didn't know (I'm self-taught so only know the basics).

I guess given I have to put in an extra core it's probably just as easy pulling through a complete cable taped to the end of the existing cable that adding a single core.

btw, I know why it was done but am I alone in thinking the new colour coding (especially three core/earth) is pretty stupid compared to the old system (all blacks and greys compared to the easy to see red/brown/blue/yellow).

 

[holmslaw]

..

 

[Steve]

Convert both switches for instantaneous switches (look the same but switch springs back), and use these to control a latching relay. No extra wiring required to the switches.

Saw a system like this in France, the hallway had about 6 switches controlling 2 lights. If you held one of the switches in, you could hear the relay buzzing in the loft.

Unfortunately, there are so many relays and contactors its almost impossible to find what you'll need online.

 

[spark1]

Neil, You say your self taught yet you say you rewired your own house
and only know the basics !!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[ColJack]

Convert both switches for instantaneous switches (look the same but switch springs back), and use these to control a latching relay. No extra wiring required to the switches.

Saw a system like this in France, the hallway had about 6 switches controlling 2 lights. If you held one of the switches in, you could hear the relay buzzing in the loft.

Unfortunately, there are so many relays and contactors its almost impossible to find what you'll need online.

wouldn't work...

once the one button is pressed, and the relay latched, you can't switch it off again.. without an "off" button..

pressing either of the 2 switches will just apply power to the already powered coil..
it would involve the use of timers and time delay elements to get it to work as a "toggle" switch..

 

[Spark123]

Think he means a system where the buttons are monentary and the pulse from these switch a device causing it to switch on/off.
Bit more complicated than need be!

 

[ColJack]

I can do it with 2 relays and a timer..
View media item 13748
push a button, timer starts..
if you release the button within 1.5s, relay A energises and latches ON...
if you hold the button, after 1.5s the timer contacts close, relay B energises and opens it's contacts, removing the live to the latched relay A

 

[securespark]

I have an even better system.

I have a relay system with PTM switches as Steve describes. The relay reacts when the PTM switch is operated by turning the light on. The next PTM operation switches the light off. Simples!

Just needs a 24V tx & a relay that switches 240V but whose coil is driven by 24V (I wanted ptm switches by the bed for the kids so 24V for safety).

But how to make them accessible.....


Got them from here: http://www.willow.co.uk/html/relays.html