Schneider Electric SOL40F3A320 is a 3-pole EasyPact Solar molded-case circuit breaker (MCCB) rated 320 A at 40 °C, built for distribution in solar and general low-voltage panels. The TM-D thermal-magnetic trip unit handles overload (thermal) and short-circuit (magnetic) protection — L and I curves. That's an F-performance class breaker, meaning it's sized for high-available-fault-current service like PV combiner boxes or main distribution boards. Rated operational voltage is 800 V AC 50/60 Hz — common for utility-scale solar where string voltages push past 600 V. Insulation voltage is 1250 V AC, giving headroom for system transients.
Fixed backplate mount, accepts front-front screw terminals on a 40 mm pole pitch. Dimensions: 205 mm high, 120 mm wide, 105 mm deep. Horizontal or vertical orientation — no derating for mounting position, but altitude derating applies above 2000 m. IP20 finger-safe on the front face, so it's panel-mount only; no washdown rating. Toggle handle for manual on/off and trip reset.
Durability and thermal profile
Mechanical endurance is 20,000 cycles; electrical endurance 4,000 cycles at rated current and voltage — typical for a distribution breaker, not a motor-switching duty class. Thermal memory is built into the TM-D trip unit, so it retains heat history after a trip and won't immediately reclose into an overloaded circuit. Power dissipation is 26 W per pole, so at full load the breaker dumps about 78 W into the enclosure — factor that into the panel cooling budget. Storage temperature range is -35 to 85 °C.