The IEE regs is not prescriptive enough to cover specifics a lot of the time.
Flex jointed with crimps in a ceiling void and protected with heatshrink on the cores plus adhesive lined heatshrink over the whole joint - OK, or not?
I have a number of GX53 surface mount fittings a bit like these for bay window ceiling lighting
The bay ceilings do not have enough space for a full recessed lamp and I need something slim as the ceiling is about 6.5ft high at that point.
I know everyone is happy with crimped and heatshrink protected joints in plaster. But how about in a ceiling void?
These things come with 2 core flex (Class II fitting). I have a small hole (1.5cm dia) already drilled with some conduit terminated 10cm or so up into the very small void, leading to the attic space.
The idea is to drop a bit of heavy 3 core flex down the conduit,
fish through,
cut the supplied fitting flex back to 5cm,
joint that to the heavier flex with crimps and 2 layers of heatshrink
(cores, and one overall, adhesive lined)
Back in the attic at the other end:
joint the flex to T+E in a BESA box on the end of the conduit (or on the end of a flexible bit of conduit joined to the conduit drop, depending on access.
Those joints will be done with lever-clip Wagos.
Needless to say the supplied flex on the fittings is too short to pull through to the attic and there's no space in the bay ceiling to be making large holes and lobbing Hager-Ashley junction boxes up there (lost of timberwork)
I would drop 3 core flex down and terminate the CPC in case future fittings required an earth. I had considered dropping T=E down, but I think its lack of flexibility would be a problem - possibly causing undue strain on the fitting flex once pushed home.
You can see I've given this a fair bit of thought - but it's not a terribly standard arrangement, so I usually like to air such madcap plans first!
Cheers
Tim