Flex used in fixed wiring

Hi all

I Am currently first fixing a new build property and the heating designer has specified 0.75mm 4 core cable to the room stats. I normally use 1.5 mm 3 core and earth for this but as each room will have its own individual stat, there will be 14 in total, so if I could cut town on space with smaller cables, that would be a bonus. The only 0.75mm cable I can find is flex but I’m reluctant to use so much of it in a fixed wiring situation as I normally use standard t&e type cable. What is everyone’s thoughts on this?

Many thanks Peter

Parents
  • Flex, and especially for signal/control like this, is normally considered perfectly OK for fixed wiring, so long as the slightly higher mechanical damage risk is addressed - so it may need a bit of trunking if it goes up the wall or along the skirting surface wired or something rather than clip direct- though in new build I rather hope it has conduit or capping behind the plaster.

    I'd not blink - the regs certainly permit it. The 0.75mm may be a bit thin if that is the only CPC to something that needs one, depends on the fuse or breaker, but that is normal rules, and the thinner floppier stuff is probably a better match to the sort of terminals on small 'stats. - avoids  the 'tail wagging the dog' problem.

    Mike

Reply
  • Flex, and especially for signal/control like this, is normally considered perfectly OK for fixed wiring, so long as the slightly higher mechanical damage risk is addressed - so it may need a bit of trunking if it goes up the wall or along the skirting surface wired or something rather than clip direct- though in new build I rather hope it has conduit or capping behind the plaster.

    I'd not blink - the regs certainly permit it. The 0.75mm may be a bit thin if that is the only CPC to something that needs one, depends on the fuse or breaker, but that is normal rules, and the thinner floppier stuff is probably a better match to the sort of terminals on small 'stats. - avoids  the 'tail wagging the dog' problem.

    Mike

Children
  • Hi Mike

    Thanks for your reply. Yes most will be either in conduit in a plastered wall or concealed above a plasterboard ceiling so mechanical damage won’t be much of a concern. I just wanted to hear other people’s opinions before I carried on but I think I’ll go with the flex, should even make connecting into the heating manifolds a bit easier too

    thanks again

    Peter