conventional multi-way switching OK ?

Yes, because in your 3+e cable you will have 2 strappers and N back from the lights. Which is the same as 2 strappers and Switched Live back to the lights

Except the light is a different place.

Owain

Surely he will need 4 cores plus earth between the first and last switch, if he has a 2 way switch circuit (intermediate third switch irrelevant), when the feed is one end of the 2 way, and the load is the other?

From the wiki, with a slight amendment to show the lamp

o---------------o o----------------o L1 / \ / L ----O X O--- LAMP-0 COM / \ / | o---------------o o----------------o | L2 | | N -------------------------------------------------------|

switch cable crossover sw cable switch lamp

That would be fine.

How would the cables normally be physically routed from one switch to the next? One wouldn't necessarily always be able to take a direct horizontal route, so then one would go vertically up, along above the ceiling, then down again, and so on [or possibly under floor instead of above ceiling].

Would you:

(A) Just route the 3+e cable as though the route were horizontal, which if the horizontal run is actually in the ceiling would mean that you have *two* 3+e cables going vertically from the ceiling to the middle switch (one coming from the previous switch, the other going to the next) [or in the case of the end switches this could be optimised to one 3+e plus one 2+e], or would you:

(B) Route 3+e between junction boxes in the ceiling and then just have a single 4+e cable going down to the middle switch [or a single 3+e in the case of the end switches]?

Yes.

Yes.

No. That way madness lies.

Keep it like the diagrams and do it the conventional way. Then whoever comes after you has got half a chance of working it out.

Besides, 4+e cable isn't to be found in most people's big-box-of- electrical-stuff-under-the-lounge-table.

Owain

I can't really think of any case where it would be easier to feed the live in one end of a two or multi-way circuit and take the switch return out of the other. Much more sanitary to run the two way circuit in triple and earth and treat one of the switches as an 'ordinary' one with the switch drop pair to it.

Indeed. Plus when first fixing you really do not want to be preparing a job that needs junction boxes. Junction boxes are usually only used for repairs and alterations to circuits.

Really? Would you not run (at least) the wall verticals in conduit (if not the ceiling horizontals as well, and is it not normal practice to have junction boxes where conduits meet?

Why? It's no more mad than the standard way of wiring up ceiling roses to a single on/off switch, where the cable from the switch has the effect of "bringing" the switch terminals closer to the rest of the circuit.

But it *is* like the diagram, at least schematically speaking. The physical layout variation is fairly minor. There's no real difference between the following two versions, except that V2 only has 5 cores running vertically, whereas V1 has eight (of which 2 are earths, so one is unnecessary, and 2 are neutral both of which are unnecessary).

Version 1: L1 ---------------------+ +------------- to next switch L2 ------------------+ | | +---------- E ----------------+ | | | | +------- N -------------+ | | | | | | +---- | | | | | | | | | | | | | | | | | | | o o | | | | | | \ / | | | | | | X | | | | | | / \ | | | | | +--o o--+ | | | | | | | +-------O-------+ | +---------------------+

Version 2: L1 ---------------------+ +------------- to next switch L2 ------------------+ | | +---------- E ----------------O--+--+---+--+---------- N ----------------+--+--+---+--+---------- | | | | | | | | | | | | o o | | | \ / | | | X | | | / \ | | +--o o--+ | +-------O

But 5-core cable is nonetheless a fairly standard product. It's just that because there's less call for it, one is less likely to happen to have some lying around.

I was thinking that it would make for a less crowded vertical conduit to have one 5-core than two 4-core cables in it.

I would only use conduit if the customer specified it. Normally I just clip the cables to the wall before it is plastered.

It is not a fairly standard product. We are talking flat cable not flex or fire rated cable.

And all that buggering about with a jucntion box is avoided.

It would work in the way you describe, but personally I would not do it as the OPs suggestion is quicker and easier.

I can. My case ! I intend to keep the area sanitary by working with the power turned off ! Simon.

you were obviously spying on my conversation last night

this sound exactly like a conversation someone had with me

except for the F, she got an f in everything

O------- A

-------O---->O------ B O------- C

JGH

Ceiling roses have always accessible terminals. A JB is likely to be hidden under floorboards, etc.

True. Although it seems always to be called 3-way. I agree it is wrong Simon.

Normally yes, but it's not too difficult to think of a situation where it would save a cable run.

Eg from the CU to a switch at the back door, up to a switch at the bedroom window on the floor above, up to the second floor bedroom if it's a tall house, then out to a floodlight under the soffit. Enables anyone at the back of the house to keep an eye on the garden, and saves quite a long run of cable.

Owain