The Siemens SIRIUS 3RV2021-4BA10-ZX95 is a motor-protection circuit breaker with Trip Class 10. It mounts on a 35 mm DIN rail per EN 60715, fits a 45 mm wide slot, and includes phase failure detection.
Short-circuit ratings and selectivity
The interrupting capacity varies with line voltage: 100 kA at 240 V, 25 kA at 400 V, 5 kA at 500 V, and 2 kA at 690 V. At 400 V the gL/gG fuse backup rating is 63 A; at 500 V and 690 V it drops to 50 A. These figures govern the upstream fuse or breaker selection for selective coordination — the 25 kA at 400 V covers most industrial distribution panels, but the 2 kA at 690 V means the breaker alone cannot clear a high-fault bolted short on a 690 V bus without an upstream current-limiting device.
Mounting and clearances
The breaker measures 97 mm deep by 45 mm wide by 97 mm tall. Required free space around the enclosure: 50 mm above and below, 30 mm to the sides, and zero forward or backward clearance — so it can be stacked tight against the back panel or a rear busbar. The screw-type terminals accept 2×(1…2.5 mm²) or 2×(2.5…10 mm²) solid or stranded copper; the main contact screws are M4. Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C.