The Square D MGP36450 is a PowerPact M unit mount circuit breaker, rated 450 A continuous at 80 % of the frame, with an ET 1.0 electronic trip unit. Three-pole, Category A utilisation, it's built for distribution duty — think main or feeder breaker in a panelboard or switchboard, not motor starting. The 65 kA AIR at 240 V AC (UL 489) means it can clear a bolted fault up to that level without rupturing; at 480 V AC that drops to 35 kA, and at 600 V AC to 18 kA. IEC 60947-2 Icu ratings run 50 kA at 240 V and 35 kA at 380/415 V. The ET 1.0 is a basic electronic trip — fixed magnetic pickup at 900 to 4500 A, no field-adjustable long-time or short-time bands. You get what the factory set, which keeps the BOM simple but limits coordination flexibility downstream.
Unit mount with lug terminations — line and load lugs accept 3 x AWG 3/0 up to 3 x 500 kcmil aluminium or copper. Tightening torque is 442.5 lbf·in (50 N·m) on the terminal nuts. The lug kit is AL800M23K. Stripping length is 1.0 in (25 mm). Operating altitude is 2000 m without derating, up to 4000 m with derating.
Current production — no end-of-life notice. UL 489, CSA, NEMA, NOM-003-SCFI-2000, and IEC 60947-2 approvals. CE marked. HACR rated. Auxiliary switch slot accepts two OF plug-in modules; one alarm switch SD plug-in; one voltage release MN or MX plug-in.