Trip Class 10 and motor protection
The 3RV2021-4EA20 is a Class 10 motor protection circuit breaker — it trips within 10 seconds at 7.2× the thermal setting, matching the startup profile of standard AC induction motors without nuisance tripping on inrush. This is the difference between a breaker that protects the motor and one that just clears a fault. Rated for motor protection, not just cable protection — the thermal-magnetic curve is shaped for the motor's overload region, not the feeder's short-circuit withstand.
At 400 V, the 3RV2021-4EA20 interrupts 25 kA. At 690 V, that drops to 2 kA — the arc extinction voltage limits the high-voltage performance. For 480 V systems, the rated short-circuit breaking capacity is 32 A, which is the continuous current at that voltage, not the interrupt rating. The backup fuse requirement at 400 V is gL/gG 63 A — the fuse clears faults above the breaker's interrupt limit, letting you size the breaker for the motor and the fuse for the fault energy. At 240 V, the breaking capacity is 100 kA — this is typical for the SIRIUS line, giving headroom on low-voltage distribution panels where the transformer fault current can be high.
Wiring and integration
Spring-loaded terminals accept 2x 1–10 mm² solid or stranded — no screw torque, no loose connections on a hot panel. The push-in entry works with ferruled wire; the spring cage holds the full cross-section. Mounting position any — vertical, horizontal, or inverted, the thermal trip curve does not shift.