2 way switching

[taycast]

Hi,

Trying to install a second switch for 2 way switching. My current switch has 2 reds in common, one red in L1 and the blacks connected behind the switch in a cable connector. How do I wire my 3 core and earth into this switch set up and into my new switch for 2 way switching? I have brand new 3 core and earth in the new colours..

Thanks

 

[Spark123]

Does this help?
//www.diynot.com/wiki/electrics:two-way-lighting

Make sure you keep the 2 red wires together as this is will be the loop out to the rest of the lighting circuit. Sleeve all 3 of the new cable colour cores in brown sleeving, you should also post a notice on the CU stating that cable colours to two versions of BS7671 in use, you can buy them from any electrical wholesalers.

 

[Steve]

Your present switch may not be 2-way! Does it have a functional L2 terminal? (Many have a hole there, but no terminal in there!)

 

[Taylortwocities]

You've got a bit of a hybrid. think it will work if you wire like this:

Keep blacks as they are

the two reds that are in com at the moment, they go, together in L2

The red that is in L1, leave it there

Your new 3 core. at both switches connect

Brown to COM
Black to L1
Grey to L2

Connect new earths to old earths

Sleeve the blacks and greys with brown sleeving.

Job done

 

[taycast]

Thanks guys for all your help. Got it working as per your ideas. My whole house lights are wired as I described with the common looping through each switch, negatives connected behind each switch in a connector. Is this unusual?? Hope not! Cheers again

 

[Taylortwocities]

Most newer houses are wired using what is called the loop-in system (see wiki for info).

Older ones have a large junction box in the loft (for upstairs lights) and hidden under a floor board for the downstairs. This isnt used now as you cannot usually access the connection box - assuming you can even find it!

Sometimes the spark takes the feeds into the switch box itself and then takes the switched feed out to the light fitting. Its not so common but its not wrong as the connections are accessible.

Glad its all working.