Gas, electric, or (steam/hot water).
You're probably OK with any of them, the electric may cause some interference. "It would be good" if you could also provide some thermal shielding, like aluminum foil with an air gap, but as long as the heat is below the melting point fo the jacketing, you're "probably" ok.
As an extra measure, if you used "plenum" rated cabling, it is designed to be a bit more resistive to heat/melting (it's still toxic to burn, but has a higher termal range).
If you want to go to the max with it, there is also "Low Smoke Zero Halogen" (LSZH) rated cabling that is the least toxic in the event of combustion. It's overkill in most home settings, since there is already so much stuff that emits toxic fumes (burning or not).
Good Luck