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Electrical

Passing lighting feed cables through PIR insulation like Celotex

Anonymous user 9 March 2024 - 2.51 PM

Hi there. Appreciate any advice.... Im currently specifying to put low power LED 5w spot lights into a cold roof construction ... with air gap void of around 80mm to fit in the spots. But the lighting feed cables need to come from above the roof joists down through the 120mm celotex PIR insulation. My question is ... does NIC EIC regs state that the feed cable should be conduit-ed / truncked through the celotex or can it just be pierced through or wedged tightly between celtex and joist? surely if its tight then the heat buildup in the cable against the flammable PIR Celotex is surely a fire risk?? What does the regs say, and against that... what is normal practice? Update 1 Thanks for the clarification Deacon ES. Appreciated. If i could be so bold as to ask someone to send me the relevant wording or paragraph or section number,... i dont have a copy of the guide and I cant find the details online.

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2 Answers

DEACON ELECTRICAL SERVICES
Rating: 5 out of 55572 reviews
Grimsby
It's not the NICEIC regs, it's the IET Electrical Regulations. Look in the Regs book(or on site guide) for further reference. If you are specifying this you need to know the regulations applied to cables passing through or in contact with insulation.
Answered8 August 2017
1

Anonymous user

Generally speaking, of your lighting circuit is wired in 1.5mm twin and earth, on a 6amp MCB/rcbo, it will be fine. The cable is rated at up to 20 amps and should be derated by 50% if ran in more than 500mm of insulation. Still allowing for 10 amp current carrying capacity. Ample.
Answered11 August 2017
0