Unusual Two-Way Wiring

John Turner · May 19, 2019

I'm in need of some help in moving a ceiling light. I'm not a qualified house electrician, but I am a retired electronics engineer, so I understand the precautions.

I thought it would be a simple enough job to disconnect the old fitting and extend the wiring to the new position. However on examination it looks like a non-standard wiring installation. In this two-way lighting circuit with just one light fitting there is no ceiling rose either on the ceiling or in the loft. The single bulb light fitting has two 'neutral wires' to one terminal and one 'live' to the other and a single earth wire. This is all original wiring from the time the house was built sometime in the ’60’s. There aren’t any safety issues with the house wiring, it's been tested and certified on numerous occasions in the recent past after work done by professionals. Can anyone please help understand this wiring arrangement?

[ElectriciansForums.net] Unusual Two-Way Wiring

Andy78 · May 19, 2019

Looks pretty straight forward to me. You just need to extend the cables in a suitable manner to the new position. I would verify the earth connection as they can often be discontinuous in older installations where alterations are evident.

John Turner · May 19, 2019

Thanks Andy. Extending the wiring doesn't present a problem for me. It's just that it's not what I was expecting. Not counting the earth, I seem to 3 wires short of a full set. The one 'live' must be the 'switch live'. And the two 'Neutrals' will be the 'pass through connections'. But were would the 'pass through live' and the 'return live' from the switch. Just very confusing.

Andy78 · May 19, 2019

John Turner said:
Thanks Andy. Extending the wiring doesn't present a problem for me. It's just that it's not what I was expecting. Not counting the earth, I seem to 3 wires short of a full set. The one 'live' must be the 'switch live'. And the two 'Neutrals' will be the 'pass through connections'. But were would the 'pass through live' and the 'return live' from the switch. Just very confusing.

It's wired in single cables not twin cables, so single conductors get taken directly to where they are needed. The neutrals will loop through the light fittings, and the line will loop through the switches with a single switch wire to each fitting. The cpc looks to be incorporated in the line conductor cable.

If you are just relocating the lighting point this should not present a problem as you shouldn't need a permanent line for anything.

As always, if you are not sure about anything, call a local electrician. If you are fine with working safely isolated and able to verify conductors through testing then crack on.

Yozza19 · May 19, 2019

Loop in at switch very ordinary in older installation s

westward10 · May 19, 2019

A system where the lives and neutrals assemble at the light fitting is known as three plate (essentially means three terminals at the plate of the fitting). The part of your circuit we can see does not have the lives passing through the fitting, these lives could be at concealed joint boxes or are linked around the switches. Your circuit is wired using 6181Y singles with the earth incorporated with the live conductor. As Andy above states you need to verify the system is still sound with regard to earth continuity.

Charlie_ · May 19, 2019

There will be a junction box somewhere or they will be part of the switch arrangements

John Turner · May 19, 2019

Thanks to Andy78, westward10 and Charlie, my mind is at rest and the body engaged

Charlie_ · May 19, 2019

Pleasure
Drop back in sometime, your electronic knowledge will come in useful for future contributions

John Turner · May 19, 2019

Thanks Charlie, I did have just one further question on this thread. Do have to extend the circuit using 6181Y or can use T&E?

telectrix · May 19, 2019

John Turner said:
Thanks Charlie, I did have just one further question on this thread. Do have to extend the circuit using 6181Y or can use T&E?

you can use T/E. or sheathed singles,

shaun1 · May 20, 2019

If you are intending to leave the joint in the ceiling void, it needs to be a maintenance free connection. Wago 773 connetors in a wagobox meet this requirement, there are also other options.

Also, the ceiling appears to be artex which could contain asbestos.

John Turner · May 20, 2019

shaun1 said:
If you are intending to leave the joint in the ceiling void, it needs to be a maintenance free connection. Wago 773 connetors in a wagobox meet this requirement, there are also other options.

Also, the ceiling appears to be artex which could contain asbestos.

Thanks Shaun, I think it would be tidier to put the jointing in the loft. Also makes it lot easier for future maintenance or changes to light fittings, especially if I leave a maintenance length of T/E in the loft. Got my full set of WAGO connectors and boxes, plenty of 1.5mm T/E, Earth sleeving, Cable Staples, Automatic Wire Strippers,Test meter, Insulation tester and always work with a dust mask with anything above my head or in the loft. With the help and advice of the other guys on this forum - think I'm good to go.

Jjc · May 25, 2019

John Turner said:
I'm in need of some help in moving a ceiling light. I'm not a qualified house electrician, but I am a retired electronics engineer, so I understand the precautions.

I thought it would be a simple enough job to disconnect the old fitting and extend the wiring to the new position. However on examination it looks like a non-standard wiring installation. In this two-way lighting circuit with just one light fitting there is no ceiling rose either on the ceiling or in the loft. The single bulb light fitting has two 'neutral wires' to one terminal and one 'live' to the other and a single earth wire. This is all original wiring from the time the house was built sometime in the ’60’s. There aren’t any safety issues with the house wiring, it's been tested and certified on numerous occasions in the recent past after work done by professionals. Can anyone please help understand this wiring arrangement?

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Frightening