Lighting circuit conundrum... Help

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Okay. So I know this is a frequent question on here but I'm truly stumped. Can't realistically afford an electrician till after Xmas but if it has to wait... It will do. I thought I would give it one last go on here.

I have FOUR three core cables coming out on my ceiling right now which were going into the old fitting.

I have bundled the four earth to tidy it up in wago boxes. I bundled what I thought were the four lives. And bundled the three neutrals, separating the switch wire.

When I double checked all the wires I found that two of the neutral wires were actually showing as live with the above set-up. The third was the switch (as expected) and the fourth seemed like the true neutral (no current).

I separated all the wires again and went through one by one testing them. Individually only ONE of the live wires is hot. If I connect one of the dead lives to the wago it's obviously rendering the dead wire live but also the corresponding neutral live as well on two of the cables.

When I started I didn't realise that this circuit not only feeds:

The hallway (where I am replacing the light) which is a two light sequence with a two way switch set up (upstairs and downstairs).

BUT also:

The side bedroom which is a single light with a two way switch (it's ridiculous).

The back bedroom which is a single light with a single switch.

Unsurprisingly nothing is working. I can't feasibly track the wires back and being the smart ass that I am I didn't take a picture (yeah, I know) because I had a quick look and was fairly confident in the set-up.

Anyone got any suggestions? Everything is isolated with wago boxes but I know it's not ideal. I can't afford 90-odd pounds for a call-out this close to Xmas.
 
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One would expect that the four cables are feed in, connection to switch, and two feed outs.

Step one is work out which is feed in. Only one red should be line.

Step two is to find out which of the blacks is the switch wire. Clearly getting them mixed up is a short circuit which is not what you want, so I would connect the feed in to a large bulb, say 100 watt, old tungsten, and the return from the bulb to the other reds, so now you can test the wires, if correct the bulb may glow a little, if wrong lights bright, so you can slowly work through the options without causing a short circuit.

Does that help?
 
Pictures of the wires will help.

If it's not obvious, try and arrange the individual conductors so you can see which sheath they are coming from.

Please confirm this is the only light fitting you have removed and there are no other fittings or switches that you have removed or replaced.
 
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Can you afford a multimeter?


Better still, a "Low-Impedance" ANALOG multimeter
(https://www.amazon.co.uk/s?k=analog...ix=analog+multimeter,aps,351&ref=nb_sb_noss_1 )
to avoid chasing "Ghost" or "Phantom" voltages -
seen via a "High Impedance" Digital meter."
 
There are a million and one ways to wire such a circuit.

You could have a feed to each bedroom going off the landing light. Which would account for 3 pairs. But then one pair could leave the landing light to feed one bedroom and another pair could leave that bedroom for the next one. So that would account for two pairs.

When I say pairs, I am excluding the CPC or earth conductor.

Is there a bathroom?
 
When I double checked all the wires I found that two of the neutral wires were actually showing as live with the above set-up. The third was the switch (as expected) and the fourth seemed like the true neutral (no current).

I separated all the wires again and went through one by one testing them. Individually only ONE of the live wires is hot. If I connect one of the dead lives to the wago it's obviously rendering the dead wire live but also the corresponding neutral live as well on two of the cables.

What is probably happening here is that you are detecting an induced voltage.

When you liven the red cable up, and the black is not connected or floating, the black can show up as live. (when it's not actually an real live)

Alternatively, if the switches are ON in the bed rooms, the live can pass thru the switch and lamp, and make the floating black cable live.

If you are sure you knew what the switched wire is, (usually identified with red or brown tape or sleeve) then I would just continue and wire it up as you intended
 
Since I have a meter, I would take each cable in turn, with power off, and connect the meter ohm range with buzzer to the brown and blue wires and flick the switch for lights, so finding out which cable goes to the switch.

I would then put the remaining wires to a block connector to keep them safe, and use the meter to find the permanent line. Referenced to earth wire, or use neon screwdriver.

So you now know two of the four cables. Next is trial and error to work out where the remaining two goes.
 

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