It's for double insulation reasons, right?

[cjard]

a wire in a wall is technically double insulated with there being grey PVC then brown/blue PVC. Hopefully, the grey enters e.g a socket box and then the box provides the secondary insulative skin while the coloured cores are exposed so the idea of double insulation persists.

Ok, so I get how we have 2 insulations up to now. I'm looking at the lighting circuit and see my spark has done it power to ceiling style rather than power to switch. I have some Fibaro remote dimmers that I need to poke up into the ceiling too.. Which brings about the question of double insulating- I like wago connectors but the wagoboxes are too big to go in the spotlight hole. The lighting wagoboxes are a tad smaller and might fit, but if the primary function of such a box is to double insulate, do I have other options for double insulating using other means? Are there any other required functions performed by a wago box (like cable retention?)
Would heat shrinking the whole lot suffice, ensuring the grey PVC is inside the shrink (the heat shrink is the secondary insulator)? How about an offcut of plumbing pipe- 40mm waste for example- with a cable tie securing the cables? Is there some accreditation a wago box/choc box has to have? (not in a maintenance free sense as above light fitting us still accessible)

essentially I'm wondering what slimline boxing in products exist for a scenario where a remote dimmer (about the size of a matchbox, with ordinary screw terminals) plus a boatload of wiring can be tucked through a 50mm hole?

 

[EFLImpudence]

a wire in a wall is technically double insulated with there being grey PVC then brown/blue PVC.

Technically NOT DI - insulated and sheathed although arguably the same result.

Single insulated wires just have to be in an enclosure.

I like wago connectors but the wagoboxes are too big to go in the spotlight hole. The lighting wagoboxes are a tad smaller and might fit, but if the primary function of such a box is to double insulate, do I have other options for double insulating using other means? Are there any other required functions performed by a wago box (like cable retention?)

The box is not technically DI either; they are primarily for cable retention.
Try Ashley J501; they are designed for the downlight hole.
https://www.tlc-direct.co.uk/Products/ASJ501.html

Would heat shrinking the whole lot suffice, ensuring the grey PVC is inside the shrink (the heat shrink is the secondary insulator)? How about an offcut of plumbing pipe- 40mm waste for example- with a cable tie securing the cables?

I suppose you could.

Is there some accreditation a wago box/choc box has to have? (not in a maintenance free sense as above light fitting us still accessible)

Just an enclosure with cable retention.

essentially I'm wondering what slimline boxing in products exist for a scenario where a remote dimmer (about the size of a matchbox, with ordinary screw terminals) plus a boatload of wiring can be tucked through a 50mm hole?

If they have a cover over the terminals and cable restraint they would be ok.

 

[Iggifer]

Wago make a wago light box FYI that's about half as tall as a normal wago box

https://www.tlc-direct.co.uk/Products/WAGOBOXL.html

 

[cjard]

I've looked at the light ones, but have never bought either. The slight challenge I have is that the Ceiling rose area has quite a lot going on. Each room has wall lights and ceiling lights, so in any one spot hole there wI'll be:

Loop in
Loop out
Wall lights spur
Ceiling lights spur
Two Fibaro dimmers
4 core (3c+e) to switch

The Fibaro dimmers effectively have a L an N in and provide a dimmed/switched live based on user instruction from a push to make switch closing two other terminals.

I Figure It'll make my life easiest if I sit on the couch in the evening and make up the dimmers with tails for the L, N and dimmed lives (maybe) so I can just push into wagos on site, rather than buggering about up a ladder trying to screw multiple cables into minuscule junction boxes

Live would need 3 way (in, out, to dimmer pair)
Neutral would need a5 way (in, out, to dimmer pair, to wall lights, to ceiling lights)
The rest of the connections are single wires into a screw hole so not bad, but then I've got to fit all that junk (2x dimmers, 5 wires, 2 wagos) into a box and thru a hole. Dare say it'd be a lot easier if I could cable tie all the cables together, and heat shrink over the whole lot, but would it cause any pulled faces?

 

[cjard]

The Ashley looks good, but ive no idea how a box cited as 54mmx28mm can go through a 50 mm hole. Might have to look for some bigger down lights if the cable tie/heat shrink is a no no

 

[slup]

Are you sure your holes are 50mm - that's pretty small.

 

[EFLImpudence]

ive no idea how a box cited as 54mmx28mm can go through a 50 mm hole.

Ah, didn't actually look at the measurements. I've never come across a downlight hole they wouldn't go through.
Can you not 'pinch' 2mm. each side?

As slup asked...

 

[cjard]

They might be 53.. Sized based on LAP's 10 pack fire dated fixed down lights picked up in a screwfix clearance.. Noting though that the adjustable gimbal ones I'm finding on eBay are anything from 63 to 85 mm holes so maybe I should just buy some bigger down lighters and drill bigger holes. At least it's easier to upsize the 50 than go down

While I'm on the topic, question for you guys..
I note the downlighters with the sprung legs have a tendency to ruin the plasterboard edge if they're pulled out. While I can't think of many reasons why the lights would be in and out if the ceiling all the time I'm struck that if there was some kind of flexible metal or plastic U shaped channel available to go round the edge of the hole it'd save the plasterboard. Something like a big version of the PVC grommets one puts in metal back boxes , maybe supplied as a long straight strip that is "cut to size and bend to fit"?

 

[EFLImpudence]

Independent thought alert!

Never seen any:
http://www.litering.co.uk/styled-2/index.html

Or just glue a plastic ring to the top of the plasterboard.

 

[Iggifer]

Or if you have access from above, just some thin sheets of ply with appropriate holes cut out, as you would for a suspended ceiling.

 

[333rocky333]

in the commercial world, you get emergency lights, in what are known as "snake packs" they are like a fire proof tubular bag, all the contents, mains inverter, batteries etc slip inside, and it cable ties shut.
not sure where you can buy the bags on there own, but would go through a 50 mm hole easy
As others say, if your looking at mr16 style fittings, they would have to have a larger hole as the lamp is 50mm to start with and as you know, gimbals and eyeballs always a lot bigger due to the mechanism.

 

[cjard]

Just a final q on this.. If it's for cable retention, how come we don't have a cable grip on a socket back box? Especially as sockets get rived on all the time, light fittings are seldom touched. Seems an odd disparity

 

[333rocky333]

a socket box is usually plastered in or screwed to the wall and a light screwed to a wall or ceiling, once fitted the wires are usually not accesible to pull them.
old style j/bs with no restraint can still be used, where the cables clipped or externally restrained.
stuff pushed through a downlighter hole is likely to get pulled in and out by the wire, hence restraint is needed

 

[stillp]

sockets get rived on all the time

???