Wall uplights - for some there's a pair of red & pair of black wires from wall, but the other has only 1 red & 1 black?

[dringa]

They're all operated by the same single switch located elsewhere.

The fittings that have pairs coming from the wall, each pair goes into a plastic joiner. Then single red & black out to the bulb holder.

The fitting that has only single red & black from the wall, there's no joiner, just direct to the bulb holder. That lamp didn't have a bulb in, the others did.

Why would there be this difference in wiring when in every other respect they're identical?

I don't know if they're in serial or connected separately to the switch.

Total amateur so apologies if this is too simple obvious, haven't found this question.

 

[Vortigern]

It's the last light in a chain hence only one wire going in and none going out.

 

[dringa]

It's the last light in a chain hence only one wire going in and none going out.

Ty. i had thoughts along those lines but was wrongly recalling the pairs only went to the joiner. I'll delete this.

 

[dringa]

Hmm, don't know if anyone can advise based on this, i fitted a joiner to the wires for that last light in the chain, so i could extend the cables so i could get the uplight back on the wall connected. But after i turned the lights on (no bulb in that last one still but i did briefly test it worked with one the other day), after about two minutes the electric for the whole building went off. I turned my lights off at the fuse box (none of my fuses had blown) then wall switch (meh).

All the electric came back on after like half a minute. I think the building has that RCD protection. I don't think it's a coincidence but i can't think why extending the wires via a joiner could cause it, i read the wires are interchangeable with lamp holders.

 

[mattg4321]

In the nicest possible way, I think it might be time to call an electrician as it sounds like you are not really competent to do anything further.

 

[dringa]

In the nicest possible way, I think it might be time to call an electrician as it sounds like you are not really competent to do anything further.

I agree, will do ty.

Think i got desensitised by the last place i was in, a rental licensed by the council, a building which repeatedly had lights/alarms malfunctions due to leaks but the council/fbrigade never enforced anything and the LL just said it has RCD protection.

 

[dringa]

Ps only thing i can think, from reading that RCD can be tripped by live to earth transfer, and that wires don't have to be touching because of the electromagnetic field, is that i left too much wire crammed into the hole in the wall around where the earth wire metal was already sticking out of the cable, that could do it? Getting electrician to check & finish it anyway.