What it is and what it does
The Siemens SIRIUS 3RV2021-0JA10-ZX95 is a motor protection circuit breaker in the S0 frame size, designed to protect motors against overload and short-circuit faults. It carries Trip Class 10, meaning it will trip within 10 seconds at 7.2× the thermal setting — standard for general-purpose induction motors driving pumps, fans, and conveyors where a fast trip protects the winding without nuisance stops on startup inrush. The breaker offers a 100 kA breaking capacity at 400 V AC (and across the 240–690 V range), so it can safely interrupt high fault currents on a strong utility feed without needing an upstream current-limiting fuse. That rating covers most industrial panel secondary-side faults.
Mounting and panel fit
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The S0 frame is 45 mm wide, 97 mm deep, 97 mm tall — fits standard 45 mm module spacing on a DIN rail. Clearance requirements: 50 mm above and below, 30 mm to the side, zero forward or backward. Any mounting position is allowed. Main circuit terminals accept 2x 1–2.5 mm² or 2x 2.5–10 mm² solid or stranded, with M4 screws. Screwdriver shaft diameter 5–6 mm. The S0 frame is a common footprint across the 3RV2 series, so a panel laid out for a 3RV1011-0GA10 will accept this breaker without re-drilling the rail or re-terminating the bus — same 45 mm width, same terminal spacing.