Borrowed Neutral???

[elementps]

Hi All,

I am looking for some help, could anyone out there please explain to me a borrowed netutral in very simple terms, as im struggling with getting my head around it?

Also test procedure to identify?

Solution to rectify when installing 17th ed dual RCD board?

Many thanks

 

[malcolmsanford]

The borrowed neutrals are as a result of the live in the “Down Lights” circuit feeding the live side of the stair head light. This light uses the neutral of the “UP Lights” circuit as its “return path” and as a result is not “electrically separate from that of every other final circuit”

Ideally you should wire the circuit properly which more than likely would mean changing the switching arrangements. Normally if a client is not prepared for the remedial then you just fit the lighting circuits on the same RCD and note on the EIC on existing installation section what you have done and why and advise that it should be changed.

 

[Sparky Ninja]

View attachment 6485
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[elementps]

Many thanks, this is much more clear than anything else I have found. Could you go into more depth on remedial works? And testing procedure?

 

[truckster]

To test for borrowed neutrals you need to IR between each neutral and the others, I disconnect one at a time and test between it and the neutral bar. As stated it's quite common to find it on stair well lighting. Remedial is generally a case of getting a live down from the upstair cct to the downstairs switch as there are usually just two strappers taken between the switches so replace the twin with a 3 core

 

[sparky1ste]

switch on both lights remove downstairs neutral out of board if landing light stays on its a borrowed neutral - plus down stairs switch will have a bridge over instead of a strapper cable - to fix it remove the borrowed neutral more than likely from the bathroom light and replace it with a neutral from downstairs light or from the c/u.

 

[SirKit Breaker]

Its an even bigger laugh when DIY charlie puts up some grotesque wall lights in his front room, and then works out that they need a neutral to work. So he quickly works out that the socket just above him in the bedroom will do, so he takes a live from the lights and a neutral from the sockets, and usually doesn't bother with an earth at all!:90:

Cheers..........Howard

 

[La Poste]

Ideally you should wire the circuit properly which more than likely would mean changing the switching arrangements.

How would you do this, change it I mean?
Edit, i should have read the whole thread before posting.