wiring a junction box with two switch circuits

[Dinsdaleyoung]

I'm replacing a light fixture which fell out of the wall. Unfortunately the wires were pulled out of the fixture so I couldn't see how it was wired. But I do know that all the available wires were attached into the back of the light fixture. The other (ceiling) light was part of the circuit and both lights were controlled independently by two switches at the wall. My query is how is it possible that the two lights were switched independently even though all the wires were connected together in the back of one light fixture?

 

[MalcofArabia]

Chances are there is a 3 core cable at your light switch. The chances are that this will be RED, YELLOW, BLUE with a bare copper cable.

The REd would be a live and that would go to the common of one switch and a link out of that to the common on the other side.

The YELLOW and BLUE would then go to the L1 of each switch respectively.

Somewhere in your circuit is more than likely one of these

http://www.neweysonline.co.uk/newle...6mm-20a/1000009505/ProductInformation.raction


In here would be all the terminations made to work the 2 lights off the double gang switch. Though without seeing the wiring it's just a guess

 

[ban-all-sheds]

It's possible because that's what lighting circuits do.

I expect you've got several other lights on the same circuit, and they're all switched independently, aren't they?

Have a read of all of the info here: //www.diynot.com/wiki/electrics:lighting

 

[ban-all-sheds]

Malc - you made the same assumption I originally did, but didn't correct yourself in time, like wot I did.

There's no reason to assume that the switch drops are shared. If he'd written

I'm replacing a light fixture which fell off the ceiling. Unfortunately the wires were pulled out of the fixture so I couldn't see how it was wired. But I do know that all the available wires were attached into the back of the light fixture. There's another ceiling light which is part of the circuit and both lights were controlled independently by two switches at the wall. My query is how is it possible that the two lights were switched independently even though all the wires were connected together in the back of one light fixture?

you'd not have assumed it was a shared switch drop, would you?

 

[MalcofArabia]

He did ask though BaS how could this be wired, I just gave an example of how it could be done.

There are numerous ways of doing it really that was just an example. I did say though it was a guess-timate without seeing the wiring.

I was wondering if by "all the cable there' he meant 3 conductors at the wall light which would be SWITCH LINE/ NEUTRAL/ EARTH. If that was the case then chances are it was done with a 3 core from switch to a JB

 

[ban-all-sheds]

Or done with a JB in the ceiling and 2 T/E drop cables to the switch.

Or the wall light has 4 terminals.

Or there were wires twisted together at the wall light (we already know it was put up by a t**t who didn't know how to use screws properly).

Or his circuit loops at the switches.

'tis best he learns how circuits work, looks at his, and works out what's going on rather than people guessing about what's likely, because if the guesses are wrong he'll just get even more confused.

 

[MalcofArabia]

Duly chastised