I bought a themostat for a new 220V baseboard heater. The thermostat is from Honeywell as is the heater, and noted "110V or 220V." I am curious how it breaks only one hot leg, and not both. (thus, single-pole)
Doesn't this leave one hot, unswitched wire at the appliance? Why wouldn't the heater work with the one hot, unswitched leg?
And yes, you can get shocked if you open the heater connection box without turning off the breaker. One leg will always be hot at the heater.
A 240 volt appliance needs both wires to complete the circuit. The thermostat only opens one wire. It is due to the manufacturer that made the T-Stat. It's much cheaper to build with one contact than with two.