Strange 2-way wiring

[telectrix]

potentially dangerous as when both switches are with common switched to L, the light is off, so Mr. layman would think it was safe to stick his sausage fingers in there.

 

[Judd]

The yanks call it a 'Carter 3-way'

 

[DjMadness]

Hi

This is a functional montage. Some electricians do it to save wires from common poles between the two SPDT switches. So instead of having two wires between each switch, a live wire to the lamp and a neutral, you need only two wires for the lamp support terminal. Bear in mind that there is a need to have L and N inside each surface mounted electrical box (pvc/...) to feed the switches. When this is not appropriate /possible they use the wiring you have in your head.


Dj

 

[Wilko]

Hmm, sounds like a grey area to me. By the letter of that reg as it's written the switching arrangement in the OP would be fine. If the reg said 'operate' instead of 'inserted' then it would apply but both live and neutral are 'inserted' so it could be argued it doesn't apply.

My thought is the intention of the reg is the N not be disconnected unless its coordinated with the L being disconnected, as per DP switching. Whereas the drawing allows N to be disconnected when L is continuous.

 

[ED17]

Are you sure it's a neutral at the switches and not just red and black used as strappers?

 

[Judd]

Are you sure it's a neutral at the switches and not just red and black used as strappers?

Yes I'm sure, why do you ask?

 

[ED17]

Yes I'm sure, why do you ask?

When I was an apprentice, (many, many moons ago) we used to run a twin red/black between switches, live down to one switch and switchwire to the other switch. Don't think my boss had heard of 3c & earth

 

[Charlie_]

That switching arrangement is very common in control circuits, relay logic, etc..