I have a 1970s home with baseboard heaters. Years ago the 2 of the heaters were unhooked from a low voltage wall thermostat. SInce the house was installed with gas heat. The heaters are 220v and wires were pulled out of the breaker box and taped off. I decided this year to install thermostats directly on each base board heater for individual control. I reinstalled the 10-2 wires back in the breaker box on with white and black to a double pole 20amp. And installed the thermostat with the power in w&b to the red and black top thermostal leads then the bottom red and black thermostat leads to the two baseboard leads. Also grounded unit with bare wire. Checked voltage at 220v to heater. Turned thermostat on a "pop" breakers kicks. What's wrong with my wiring?