I am installing a wood burner with a false chimney breast around a double skinned flue. The chimney breast will be metal stud (or do you only call it a stud if it's wood?) with fire board as per regs about distance between the flue and combustible material. I have several wires that I would like to run down the inside of the stud work, like you would for a normal dry wall. Is wiring combustible? If so is there a trunking that I can place it in? I could get metal trunking – this would stop it burning, but would it stop it melting!?
I've found quite a few other similar questions, however I wasn't sure in most of them if the fireplace was in use/if they were asking if they could use the old flue as a duct for wiring!!
Best Answer
I don't think it would be a good idea.
It would be vital you to know the possible ambient temperature of the space you are running you're conductors or cabling while the heater was running. Basic apprenticeship instruction teaches that heat has the greatest effect on the function of your circuitry.
NEC Table 310.15(B)(2) shows the multiplier you should use when calculating the current carrying conductors when your ambient temperature exceeds 104F or 40C. Even if you were using 90C insulation if you exceed 80C or 170F you should not use it at all. This would not melt the insulation and is certainly below combustible material levels, but it would effect your circuitry and its ability to carry current.
So if you have no other option but to run new circuits down this chase. You really need to be absolute on the ambient operating air temperature and the types of electrical methods and material you can use to make it safe.
If this sounds like a little much for yourself as an individual, you might need to consult a professional to make the necessary calculations and recommendations.
Good luck and stay safe.