Single & Earth

[dingbat]

Given that nobody manufactures either a back box or a switch designed to loop in twin & earth cable via switch positions, why does nobody appear to make single and earth cable any more?

Anybody know if such a cable is still available?

 

[sparkydude]

yes it is still available, not normally off the shelf though has to be ordered in , Bit like pyro these days , nowhere to be found

Nick

 

[RF Lighting]

Yeah we still use it.

At the risk of being flamed down, our local CEF has it on the shelf

 

[dingbat]

Is that the CEF on Gelderd Road?

I'm seriously thinking of going back to looping phase via switches and neutrals via lights - it makes so much sense when you know that replacement lights will be fitted as soon as your back is turned.

 

[bernardgreen]

Is that the CEF on Gelderd Road?

I'm seriously thinking of going back to looping phase via switches and neutrals via lights - it makes so much sense when you know that replacement lights will be fitted as soon as your back is turned.

Separating the live and neutral feeds will increase the amount of radiated 50Hz magnetic fields from the wiring. This can create "hum" in audio equipment

Looping live and neutral side by side in a single cable means two currents (live and neutral) oppose and cancel each other.

 

[ColJack]

i may be being a bit dumb, but i don't get wht you are saying in the original post..

they make backboxes up to 45mm deep, and switches can be double pole..
where's the problem?

stop being cheap and use a decent make of grid switch..

do people really not just loop live and neutral to lights and then switch drops anymore..?

the agrument of "hum" should not be issue here either since current flows down the live wire, and back up the switch wire..

 

[Adam_151]

Separating the live and neutral feeds will increase the amount of radiated 50Hz magnetic fields from the wiring. This can create "hum" in audio equipment

Looping live and neutral side by side in a single cable means two currents (live and neutral) oppose and cancel each other.

Was just about to say the same myself, I have been 'slightly' involved in ham radio in the past (have an M3 callsign) helps me to be a bit aware of things like this , want to some day get back into it, but not right at the moment

 

[securespark]

I have been 'slightly' involved in ham radio

Or should that be "hum" radio???

 

[plugwash]

do people really not just loop live and neutral to lights and then switch drops anymore..?

Some do but it makes fitting most fancy light fittings a bitch, they just don't tend to be designed with enough wiring space for 3 T&E cables and an extra joint.

 

[dingbat]

i may be being a bit dumb, but i don't get wht you are saying in the original post..

Three-plate wiring is great for the spark - piece of pish.

But 'designers' are [almost by definition, it seems] people unacquainted with how anything works, so they don't accommodate this practice.

Solution then, is to loop via the switches, which is great on a new-build, but can be problematic on rewires, where access is often tricky

they make backboxes up to 45mm deep, and switches can be double pole..
where's the problem?

For single switches, no problem, but try and be friendly to the future occupants and fit a three-gang switch with one of them the start of a two-way arrangement and you have a lot of wires to fit into that box, however deep .

stop being cheap and use a decent make of grid switch..

Quite often do, but it's not the answer.

the agrument of "hum" should not be issue here either since current flows down the live wire, and back up the switch wire.

The argument of hum wouldn't be an issue if you were rewiring like for like, either. (Or for almost every inhabitant of almost any house in the land, as it happens.)

 

[Adam_151]

I would suggest a circular drylining box in the ceiling, but that would be problematic if any one wanted to fit a big light, or one of those fans (was thinking that with these the base is normally bigger and would cover the box and screws would go outside of it, but then realised that it wouldn't work, because the circ box would have to be off-centre because of the joist, although you could perhaps fit it away from joists, and place a noggin over the top of it)

 

[ColJack]

with loop in wiring you then have 3 cables going to a single light switch..

live in, live out and switch.. fine if it's a stud wall but a PITA if it's a plastered wall..

metal capping should reduce "hum" if it's earthed..

i make it a point or putting a piece of 12 or 18mm ply behind every ceiling rose, about 12 inches wide fixed to blocks and screwed to the joists..

i guess that's because most of my work has been comercial / industrial and I'm used to putting 2' square boards behind the tiles of ceiling grids..

 

[dingbat]

I would suggest a circular drylining box in the ceiling, but that would be problematic if any one wanted to fit a big light,

It's also problematic for many small lights as well - some bases are miniscule. And what about when they decide to fit the dreaded downlights?

The problem remains that most modern lights will not accommodate more than one multicore cable and as soon as an untrained person gets their hands on those 'extra' cables non-compliances will follow; one 'solution' I encounter regularly is to choc-block the live conductors, shove 'em up into the void and forget about the CPCs altogether.. after all, as every builder knows, they don't do anything, do they? (As it happens I took down four such arrangements this afternoon... )

I still reckon single & earth is a good idea.

 

[dingbat]

metal capping should reduce "hum" if it's earthed...

Please don't re-introduce the ridiculous notion of earthing capping... we'll be here all week!

 

[Adam_151]

I personally like the looping at the switch, but if its too troublesome to get the cables there... chase in a deep enough box because of building layout... then why not loop at the light as normal, it makes it a bit more tricky, but most lights have enough room in the base to squeeze them in along with a slightly longer bit of choc block, might be fiddy but I think it can usually be done