What the AC-3 rating means for the panel
The Siemens SIRIUS 3RT2046-1AP04-3MA0 is a Size S3 power contactor rated for 96 A at 480 V in AC-3 duty — the standard category for starting and stopping squirrel-cage induction motors under load. That 96 A figure governs the motor full-load current it can switch, not the resistive heating current. For a 480 V three-phase motor, 96 A AC-3 corresponds to roughly 60–70 kW, depending on the motor's power factor and efficiency. The contactor is also rated for 20 hp at 230 V, confirming its fit for North American motor branch circuits at that voltage. The AC-3 switching frequency is 850 operations per hour maximum, with a mechanical life of 10 million operations typical. That means in a conveyor or shuttle application cycling every 30 seconds, the contactor stays well within its rated duty cycle for years before mechanical wear becomes a concern.
That 20 mm forward clearance is the critical dimension for arc chute venting and for screwdriver access to the main terminals. Main circuit terminals accept solid conductors from 2.5 to 16 mm² and stranded from 6 to 70 mm². The coil terminals are screw-type, accepting 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²). The 70 mm² stranded capacity on the main poles is generous for a Size S3 — it allows paralleling conductors for high-current runs without needing a terminal adapter. Physical dimensions: 70 mm wide, 140 mm high, 195 mm deep.