The Schneider Electric GV3P321 is a 3-pole motor circuit breaker from the TeSys Deca range, rated at 32 A continuous current with a thermal protection adjustment range of 23...32 A. This is a thermal-magnetic trip unit with phase failure sensitivity per IEC 60947-4-1 — if one phase drops, the bimetallic element in the other phases sees elevated current and trips faster than a standard three-pole breaker would. The utilisation category is AC-3 for motor switching, and it is rated for uninterrupted duty, so it can stay closed continuously carrying the motor's full-load current.
At 55 mm wide, it occupies a standard three-module footprint on the rail. The rotary handle provides manual on/off control and a clear visual indication of contact position — useful for lockout/tagout procedures on the line. Operating altitude is rated to 3000 m without derating, and the enclosure carries IP20 protection (touch-safe terminals) plus IK09 mechanical impact rating for panel environments. Mounting position is horizontal or vertical, so it fits in tight enclosures where you need to rotate the rail. The screw-clamp terminals accept up to the listed tightening torque of 5 N·m — worth confirming your ferrule size matches the terminal opening if you're re-terminating in the field. Climatic withstand conforms to IACS, so it handles the humidity and salt-spray conditions typical of marine or coastal installations.
Key ratings in context
Motor power capability: 15 kW at 400/415 V AC, 18.5 kW at 500 V AC, 22 kW at 690 V AC — all at 50/60 Hz. These are the numbers you match to your motor nameplate. The rated insulation voltage (Ui) and operational voltage (Ue) both go to 690 V AC, so the breaker is not the limiting factor in a 480 V or 600 V system. Electrical durability is 50,000 cycles under AC-3 at 415 V at full rated current — that's the motor-switching life, not the mechanical life (also 50,000 cycles). For a motor start every two minutes, that works out to about 70 days of continuous cycling; in most industrial applications with a few starts per hour, it will outlast the motor. The mechanical robustness specs (15 Gn shock contactor open, 30 Gn closed, 4 Gn vibration 5-300 Hz) mean it holds calibration under the vibration from adjacent contactors or conveyors.