Switch for light?

MarcusMaximus

I want to put up a light for illuminating a painting. There is an unused switch nearby that I was hoping to use. However whereas the light takes a standard live, neutral and earth, the switch is on a loop circuit with only one live wire going in, connected to the Common terminal, and another coming out that sends the power out again, depending on the position of the switch. Sorry if this is obvious.

I don’t know where the grey cable finally ends up as it doesn’t do anything but it was possibly to an old external light as the switch is beside the front door. Anyway, can I use this to power the light and if so, how do I connect it?

10-10-20

That's a (miswired) one-way switch.

https://flameport.com/electric/lighting_circuits/lighting_switchwires_oneway.cs4

The miswire part is where they used green (earth) cabling for the live or switched live.

You can't use that as it has no neutral or earth. 😕

blackbox

On older installations it was normal not to have an earth or neutral at the switch. The neutrals were connected at the ceiling rose and lights weren't normally earthed. It was safe enough when switches and light fittings were plastic, but there is a risk if these are metal.

I'm not sure when the rules changed.

However using a green wire for live was never normal.

Cerco

https://www.boards.ie/discussion/comment/123920662#Comment_123920662

I think using a different colour wire was permissible, and maybe still is, if there was an indicator that the wire was live. For example a piece of red or brown sleeving slid over the end of the wire. Obviously that was not done here.

I am open to correction.

10-10-20

https://www.boards.ie/discussion/comment/123920776#Comment_123920776

That's right - see the examples in the link I provided, but I'm not sure that it applies to earth coloured wiring!

MarcusMaximus

https://www.boards.ie/discussion/comment/123920617#Comment_123920617

Yes that's what I thought, though I'd hoped I could maybe use the live for the supply and then 'hijack' a neutral and earth from somewhere nearby.. 🤔 🫢

Thanks for the link, yes strange that they used a green wire without any warning that it is live! The more I go beneath the surface in this house between one job and another, the more hacks I discover. Like the huge cavity in the external wall in the bathroom where the sink and bath waste pipes exited. Looks like they literally smashed out a hole, stuck the pipes in and then called it a day. No wonder it has always felt cold in there!

Still the house is grand for the most part so I'm not complaining. 😏

10-10-20

https://www.boards.ie/discussion/comment/123921166#Comment_123921166

Taking the term 'builder's finish' to the extreme alright.