2 switches to the lights

[Vass]

I think I have found a work around but am curious if my first idea was valid? I have a staircase that was moved. 2 switches top and bottom, but no light at the bottom. I want to install one, but the circuit runs in the loft. I can pick up the Live feed from the two switches easitly enough, but to bring the neutral down would mean chopping out. My theory was to pick up a Neutral from the downstairs light circuit. I've not done this because it would confuse the 2 trips on the CU, but would it have been possible? In the end I took the light feed from the upstairs light and took another cable inside a bedroom cupboard to get to the downstairs. TIA oh and MC HNY

[John]

I think that if you look inside the CU then you will find all the neutrals are fixed to a common terminal bus bar.

[Vass]

So I'd have ben ok to do it?

[fred]

In article , Vass writes

I'd consider it bad practice to cross connect the neutrals from different MCB circuits at any point other than the CU, it would upset testing and fault finding at least but I am not an electrician.

It's also bad practice to create loops between live and neutral, it can lead to electromagnetic interference problems, the loop acts as a large aerial.

[Andrew Gabriel]

You are not permitted to mix neutrals on different circuits. It can result in electrocution of someone working on a circuit which they think is isolated, but which is being backfed by a cross-connected neutral which is still live.

If either of the circuits are RCD protected, it won't work either.

[Dave Plowman (News)]

Never seen a split load unit?

But it's not the point. 'Neutral borrowing' can be dangerous at worst and is very bad practice at best.

[John]

I appreciate the clarification to my point that all neutrals are connected to one bus at the CU.

Thanks

[<me9]

The original wiring of this house (by a nic/eic registered installer) had the landing light off the downstairs live via 2 way switching and the upstairs neutral. I found this out the hard way.

DO NOT MIX NEUTRALS ON TWO DIFFERENT CIRCUITS!

[Dave Plowman (News)]

You're wrong.