Borrowed neutral - again!

[KeenPensioner]

This is the crux of it: Economy. The 'downstairs line / upstairs neutral' configuration allowed the installer to run just a twin + earth strapper cable between the switches instead of 3C+E, thereby avoiding having to stock 3C+E or make two runs of T+E.

With 3C+E, any of the normal 2-way configurations is possible without any borrowing. For 'conventional' 2-way one permutation is to carry L1, L2 and PL through the strapper cable to the downstairs switch. But by picking up the PL from the other gang of the 2g, only L1 and L2 need to be run.

Thanks for the reply. All this time it was simply to avoid carrying a stock of 3 core. I have been trying to figure this out for ages. I can't believe it was that simple!!
Thanks to everyone who helped me on this.
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Thanks to everyone who helped me on this. All this time it was simply to avoid carrying (or not having) a stock of 3 core. I have been trying to figure this out for ages. I can't believe it was that simple!!

 

[captaincaveman]

Bit late reading this thread lol. But it just occured to me to use a kinetic switch to overcome this problem. I've found a good reliable one for £30 (a lot cheaper than a couple of years ago) which I've used in garden lighting a couple of times. I think I'll give it a go with a replacement ccu job I'm doing. That way I can still have the split lighting still and at not much extra cost

 

[EricMark]

The problem has now become worse, with the use of Smart relays, and having the switches switch extra low voltage.

I have found with my own house an intermittent fault with the light switches, the lamp is not easy to access, needs an access platform, so when the light switch failed, I did not jump in to fix it, next day was working again.

However since we rarely use the switches, it does not really matter, we have got use to saying hey google turn on or turn off, or use the phone.