The Siemens 3RV2021-1EA10-ZW96 is a SIRIUS motor-protective circuit breaker designed to protect motors against overload and short-circuit. It carries a 100 kA breaking capacity at 400 V AC, which means it can safely interrupt fault currents up to that level without upstream fuses — a strong SCCR headroom for direct-on-line motor starters in industrial panels. The Class 10 trip characteristic matches the thermal time constant of standard induction motors, so it lets inrush pass but catches a locked-rotor condition before the winding insulation degrades.
Compared to the sibling 3RV2021-1FA15, the 3RV2021-1EA10-ZW96 shares the same 45 mm width and Class 10 trip class. The -ZW96 suffix indicates a special version.
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width takes up one standard module slot, leaving space for a contactor and overload relay in a motor starter group. Phase failure detection is built in — no separate phase-monitor relay needed. Screw-type terminals accept 2x 1…2.5 mm² or 2x 2.5…10 mm² solid/stranded, so common panel wire sizes land without lug adapters.