2-way switching and Neutral as well!

Jan 15, 2012 15 Replies

After asking about running Neutral to a switch I decided to put both lights on to 2-way. Looked for diagrams - although the circuits aren't complex, the colours seem to be variable. The only tip I had was from Adam re. using incoming grey as Neutral. Looked at several diagrams that I found and most of them, including the Wiki, are using the old colours. I also want to run the supply and both lights from one switch and almost all digrams show one light from each switch. Anyway, I've done a diagram in LibreOffice Draw (couldn't quickly find any Freeware for the purpose) and have put it up as a .png. I think that the wires aren't crossed and that the colours are OK, but...!



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Which wiki were you looking in? Ours uses new colours:

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I also want to run the supply and both lights from one switch and almost all

close to being a functional equal to:

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the exception you have shared a permanent live strapper...

But the circuit looks fine. It is unconventional as you would normally use two 3 core and earth cables between the switches, but that is not a rule. I have done similar installs where I was passing the cables through existing conduit that would not take 2 x 3 core and earth cables and there had to be no damage to the downstairs walls.

I have a query regarding lighting....

in my house, the hall light is powered from the downstairs lighting MCB at the CU. The landing light is powered from the Upstairs lighting MCB at the CU. I have at both the landing and the hall 2 gang 2 way switches, allowing me to control both lights from both locations.

Is that still allowed within the wiring regs as there is no physical separation between the two lighting circuits within the metal back boxes?

Regards,

Stephen.

The answer is a very simple "YES, it is allowed".

You will not be the first or last to ask that one:-)

well I am pleasantly surprised given that if you wish to work on the light switch, you have to de-energise *two* lighting circuits for safety reasons......

Stephen

I sometimes have to de-energise more than two circuits to change a lightswitch:-)

Just one of those things to be aware of if poking about in the back of switches.

one, as they show a light from each switch.

By using the strapper I can get the cables into the conduit - live is live (on single phase :-) )

At the cost of much effort and some skin from my hands I've put both of mine, including Neutrals, on the downstairs circuit. Although the upstairs circuit at the time had less load, I've since put 77W of CFLs in the loft (~150VA) and if I fit outside lights they'll be under the eaves so that they're aimed down and don't dazzle people in adjacent gardens.

That's the main reason - the cables! Been fun trying to get it all in the patress: 13 wires+sleeving+strap and, if I change the second fitting to one that needs an Earth...! I'm using patresses that are nominally 19mm; I've a 20mm but the base is thicker than usual. Dropped lucky by looking at MK plates, as the terminals are angled so no wires need to pass behind the switches themselves.

Only 13 wires including the earth!

The next time I go behind a 24 module grid switch will take a photo:-)

I know plumbers pee in loft tanks but really ...

Owain

Is that module in a 1-gang patress then? I was seriously tempted by a 25mm box, I must admit.

Perhaps he's a crap photographer!

photo:-)

It's OK Adam knows to switch off, isolate, dump and earth.

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