Author Topic: Re wiring a 3wire light switch  (Read 244 times)

velosam

  • '.....you used to be an apple on a stick.'
Re wiring a 3wire light switch
« on: January 06, 2019, 08:15:33 pm »
Can I wire a 3wire light switch into a two wire switch i.e don't wire the neutral?

My garage switch is broken and my spare switches are all 2 wire.

Thanks

Feanor

  • It's mostly downhill from here.
Re: Re wiring a 3wire light switch
« Reply #1 on: January 06, 2019, 08:23:15 pm »
3-wire light switches (if they are using all 3 terminals ) are wired for 2-way switching, and will need to be replaced like-for-like.
If only 2 of the terminals are used, and it's the only switch controlling this light, then yes, you can use a 2-wire switch.

There's not usually a Neutral at most light switches.
( There can be, but they will all be connected together in a chock-block at the back of the box, not to the switch itself. )

So usually, no.
Replace like-for-like unless you really know what you are doing.

Or post a clear photo of the existing wiring.


velosam

  • '.....you used to be an apple on a stick.'
Re: Re wiring a 3wire light switch
« Reply #2 on: January 06, 2019, 08:34:11 pm »
Thanks .  Will have to buy the same one.  It a metal switch in the garage and the neutral wire is connected to the metal faceplate with two wires connected to the switch.

I have some plastic switches which I thought could be a quick replacement as I am trying to avoid a trip to Wickes before the weekend!

Re: Re wiring a 3wire light switch
« Reply #3 on: January 06, 2019, 08:52:28 pm »
That doesn't sound like a 2-way switch, and only an earth wire should be connected to the body of a switch.

Feanor

  • It's mostly downhill from here.
Re: Re wiring a 3wire light switch
« Reply #4 on: January 06, 2019, 08:55:37 pm »
There will not be a Neutral wire connected to the faceplate.
That will be an Earth wire.
Usually, an un-insulated conductor running between the two insulated conductors in a Twin-and-Earth cable.
It should be sleeved in green-and-yellow sleeving in the back box.

It sounds like a 2 wire switch will be fine.

If your new switch don't have an earth connection, then terminate the earth wire at the terminal in the metal back box, or if there is none, then just terminate it in a single chock-block to keep it out of the way.



velosam

  • '.....you used to be an apple on a stick.'
Re: Re wiring a 3wire light switch
« Reply #5 on: January 06, 2019, 10:31:44 pm »
Thanks -  it is sheathed in yellow and green so will just terminate it in the metal casing box which sits on the wall

hulver

  • I am a mole and I live in a hole.
Re: Re wiring a 3wire light switch
« Reply #6 on: January 07, 2019, 10:28:34 am »
velosam,

If you don't know what an earth wire is, you really shouldn't be touching your house electricals.

Seriously, that stuff is dangerous.