The disconnect switch satisfies National Electrical Code requirements for a safety disconnect between the solar array and the controller. During installation and maintenance, switch off the disconnect switch to prevent shock and arc burn hazard.

Overload protection (fuses or circuit breaker) is NOT required in the solar array circuit.

1. Short circuit current from the solar array can never reach the ampacity (maximum safe amps capacity) of the recommended wire.
2. The PS- controller has internal overload protection.

Loose connections are a comon cause offailure. Pull each connection to confirm.

If you are not using a low-water probe, connect a small wire between terminals 1 and 2.