Lighting circuit puzzle

[Bannon]

I'm doing a renovation (aint we all!) and am rather puzzled by my lighting circuit. I have three red cables coming from the fuse (box) which feed the downstairs lights. I expected to see just the one red cable but three? Whichever one I disconnect, all downstairs lights cease to function.

Any ideas guys before I rip the lot out and start again?

 

[Spark123]

Do you mean all the downstairs lights cease to function when one wire is removed, or a few of them for each wire - it may be that it has been wired so there are in effect 3 radials from one fuse, not wrong btw.

 

[Bannon]

Thanks for your reply.

Removing any of the three causes all the downstairs lights to stop working. I had thought that two would be radial as you say but three?

Just a thought though , it might something to do with two of the switches working in tandem (you know the thing - either one or the other switches off the same light. What do you think?

Cheers.

 

[wingcoax]

If you are talking about two way switching, that should have no effect on the loss of all lights. Do any of your upstairs lights go out?

 

[ban-all-sheds]

I think I can't begin to think WTH is going on.

Let's treat the entire G/F lighting system as a "black box" - i.e. it does whatever it does with its lights and switches, but that's irrelevant - it is a self contained system supplied from the CU.

And if you wanted to make it exhibit what yours does, I can see how you could do that with a couple of contactors in series, or some logic circuitry, but why?

I guess what I'm saying is that I can't conceive of any mistakes someone could have made that could bring this about by accident, only deliberate ways to make it do what it's doing.

Can you identify the neutrals? Are there 3? Does the same thing happen if you disconnect any of them?

 

[shadyspark]

are you sure removing any 1 red stops all lights? a lot of the times i see that its usually lights, alarm and doorbell circuits on the one fuse

 

[ban-all-sheds]

are you sure removing any 1 red stops all lights?

He seems pretty sure of that.

Whichever one I disconnect, all downstairs lights cease to function.

Do you mean all the downstairs lights cease to function when one wire is removed, or a few of them for each wire

Removing any of the three causes all the downstairs lights to stop working.

 

[Bannon]

Thanks for all your replies guys.

I used to work as a TV engineer before retirement so I know things are not always as they seem - and I'm also a convert to all aspects of Murphys Law (or Dumkoffs Law if your name is Murphy!)

Yes, any one of the reds disconnected in turn and all downstairs light go out with upstairs being unaffected. Half the problem is that most of the existing cables run through areas where I cannot get to which is a real bugger. Seems I'll just have to get back up into my very small loft, rummage around in the fibre glass, and trace back each cable. Tried doing continuity checks but that gets me scratching my old head even more.

The property was used as a light industrial unit/cottage showroom making hand made paper so a lot of the existing wiring which I've now taken out was used for things like spotlights and power for workbenches.

Anyway, thanks again guys.

 

[jj4091]

I'm doing a renovation (aint we all!) and am rather puzzled by my lighting circuit. I have three red cables coming from the fuse (box) which feed the downstairs lights. I expected to see just the one red cable but three? Whichever one I disconnect, all downstairs lights cease to function.

Any ideas guys before I rip the lot out and start again?

Can you just confirm that all 3 reds are connected together in the same fuse outlet, rather than them going to different places in the consumer unit. Also why would you need to go into the loft for your downstairs lights( the plot thickens )

 

[sparkwright]

Is the cabling in twin and earth cable, or singles/singles in conduit?
Any junction boxes?
Do you have the same number of neutrals at the board?

And you're certain disconnecting any of the lives at the board cuts off the SAME lights every time?

This situation defies all logic.

Any pictures you can take of the board and random switches, roses, etc may prove helpful.

 

[Bannon]

It's all twin and earth so not quite out of the ark sparkwright, can only guess at junction boxes so probably on that score, and yes, same number of neutrals on the cu. The same number of lights go off I'm sure - but I'll re-check that. The three reds are all connected to the same fuse.

It is crazy I know.

Ah yes the loft. The house is split level with the lower loft running out to a kitchen and bathroom on the same level as the rest of the ground floor under and extended roof slope.

 

[ColJack]

do some of the lights come back on if you isolate the wire you've removed and turn the breaker back on

 

[shadyspark]

without using any powered swithgear can anyone tell us how its possible to wire a circuit where removing any off the 3 legs eliminates power to the lighting points completely?

 

[ColJack]

we need pictures of these wires exiting the fuse.. and th fuse itself..

it IS a fuse isn't it and not a 3 phase breaker ( well he did mention light industrial unit.. )..