How do you wire a firefighter's switch for a pool heater?

To wire a firefighter's switch for a pool heater, first ensure the power is turned off to the heater at the circuit breaker. Connect the incoming power supply to the switch terminals, ensuring to follow the manufacturer's wiring diagram, typically involving connecting the line and load wires correctly. The switch should be wired in series with the heater's power supply, allowing it to cut power to the heater in case of an emergency. Finally, secure all connections and enclose them in a junction box for safety before restoring power.