Junction Boxes in Lighting Circuits

[TheScullster]

Hi all

Some progress on the kitchen front! OK, so I believe "we" have an agreed layout, so I have started preliminary wiring/routing in readiness. The kitchen is single storey and concrete floor so is wired from the loft down. My question really relates to the use of junction boxes for terminating wiring, rather than at the fitting. There have been numerous complaints recently concerning lack of available space at the fitting itself to terminate switch wires, loop in power etc. and also I think comments about using choc blocks pushed into ceiling spaces and the like.

So my solution will be to create a "wiring centre" on the loft wall. This comprises 3 junction boxes for concealed lighting, main lighting and outside lighting mounted on the loft wall above the switch drops. Loop in and switch wires will be terminated in these junction boxes, with single supply feeds radiating to each fitting/location.

Are there any regs-related issues that would rule out this scheme?

TIA

Phil

[Tim Watts]

On Mon, 14 Jun 2010 10:54:07 +0100, "TheScullster" wibbled:

Hi Phil,

Only regs applicable is that the junction box is either accessible for checking the screw tightness, or is suitable for a non accessible location.

Which does yours fall under? Accessible I presume as you said "loft"?

Otherwise, it is an excellent idea.

[Roger Mills]

I don't think so. If you're using junction boxes with screw terminals (as opposed to crimping or soldering), they're supposed to be 'accessible'[1] - as yours presumably will be.

[1] I'm not totally sure what that means - I think probably not buried in plaster etc. I've got quite a lot under floor-boards - not sure whether that qualifies or not!

[ARWadsworth]

If there is a loft hatch then it an excellent idea. If the loft hatch is some distance from the wiring centre then it may be better to reposition the wiring centre onto a wooden board above any insulation that is closer to the hatch.

Adam

[Spamlet]

Reminds me of something I've been meaning to ask. Being of poor memory and limited brain power, whenever I have to use a junction box for a light and switch, I seem to find myself staring blankly at 4 connector poles in a square arrangement and wondering why on earth, in the ceiling fittings they give you a whole row of oodles of connectors that you can rarely squeeze the cable into, but in a junction box they leave you a complex topological puzzle as how to arrange everything in a square. I always end up drawing a circuit on paper first, as I find the square arrangement so counter intuitive and confusing. (Yes, I know you can get boxes with the poles in a row, but when I bought my last lot from Screwfix there was nowhere to specify this...)

So folks, why square and only four poles in a junction box, but oodles in a line in a ceiling fitting?

Cheers, S

[Tim Watts]

On Tue, 15 Jun 2010 00:43:39 +0100, "Spamlet" wibbled:

There are 6 pole round JBs (2 extra in the middle). Don't forget, you can also twist the earths loosely outside the box to get an extra pole[1]

[1] Nooo! But I have seen boxes where some cheapwad thought this was a good idea...

Anyway, you might like the Hager-Ashley JBs - 4 cable entries and 4 poles, arranged "on the flat". Lots of room and cable clamps too. Like a breath of fresh air.

[TheScullster]

"ARWadsworth" wrote

Nice idea Adam, but the question was a little retrospective, the JBs are already mounted and some cables pre-run. I was really just concerned that I hadn't done something that had been outlawed recently by the ever-changing regs.

The loft is fairly small with a good size hatch, so although the wiring centre isn't next to the hatch, it's only a hop and skip away.

Phil

[TheScullster]

"Tim Watts" wrote

If I'd been aware of those before I started, I would probably have been tempted. As it is, the JBs are mounted and trunking run and I simply don't have the energy for re-work.

Phil

[ARWadsworth]

That is fair enough. As long as they are not crammed away in a corner/eaves that you cannot get to then that is fine.

Adam