Two baseboard heaters connected to one thermostat.
Wiring Diagram For 240 Volt Baseboard Heater
Wiring Diagram For 220 Volt Baseboard Heater
How Does an Electric Baseboard Heater Work? For 120 volts Black heater wires are connected to one of the heaters.
This will cause the wire to short out.
Additional heaters allow the room to maintain desired temperature during the colder days, as opposed to having the minimum heat or baseline installed.