I'm remodelling a house, circa 1950, built when ceiling electric heat was subsidized by the power company. I expected to find some type of flex panel with heating coils between the joints.
Instead, I found one wire sandwiched between two layers of sheet rock on a portion of the ceiling that fell down. The wire is non-copper, probably nichrome or some other high resistance alloy. The insulation is labelled for Radiant heating and rated at 90oC. Each room has it's own thermostat and the system works well (where intact.)
I've not traced the wiring back to the circuit breakers. Is anyone familiar with this system? Can a single wire between joists truly be the only heat source? Does it run at 220 or 110 volts normally?
What little I've seen is 240v with copper or aluminum branch circuits to the thermostat. The heating wire is run to the ceiling and run back and forth on the wallboard and then coated with a plaster-like substance. Works fine until it doesn't. Usually due to someone putting a screw through the wire.