The Siemens 3RV1021-0EA10-ZW96 is a SIRIUS motor protection circuit breaker rated at 0.4 A continuous current with Trip Class 10 thermal overload protection. It breaks up to 100 kA at 400 V AC, covering fault currents on motor branch circuits up to that level. Phase failure detection is built in, so a lost phase trips the breaker instead of cooking the motor on single-phase.
DIN rail fit and wiring
Snap-on mounting to 35 mm DIN rail per EN 50022, with screw-type terminals on both main and auxiliary circuits. The 45 mm wide body accepts solid or stranded conductors: 2x (1... 2.5 mm²) and 2x (2.5... 6 mm²) per terminal. Depth is 96 mm, height 97 mm — fits standard distribution boards without crowding the gland plate. Mounting position is any, so it works in vertical or horizontal panel layouts.
Breaking capacity and duty cycle
Rated short-circuit breaking capacity holds at 100 kA across the voltage range: 240 V, 400 V, 500 V, and 690 V AC. That's consistent fault clearance regardless of supply voltage within the rated range. Maximum operating frequency is 15 operations per hour at AC-3 duty — fine for motor starting, not for rapid cycling. Power dissipation is 5.5 W hot, 1.8 W per pole, so derating in a sealed enclosure is worth checking if you're packing multiple units.