The MGP36500YP is a Square D PowerPact M unit mount circuit breaker — 500 A, three-pole, with an electronic trip unit. It interrupts fault currents up to 18 kA at 600 VAC, which covers most industrial panel secondary-fault scenarios below that threshold. The unit-mount form factor bolts directly into switchboard or panelboard buswork, not a DIN rail; the lugs-off-end termination suits line-side feed from bus bars or cable.
The 500 A frame and electronic trip give you adjustable long-time, short-time, and instantaneous pickup — the trip curve is field-configurable, not fixed like a thermal-magnetic. That matters when coordinating with downstream feeders or motor starters. Handle padlock provision is standard for lockout/tagout compliance without an accessory kit.