What it is and what it does
The Siemens SIRIUS 3RV1011-1FA15-0BA0 is a motor protection circuit breaker — a single device that combines a thermal overload relay and a magnetic short-circuit trip in one 45 mm wide package, sized for a 5 A continuous rated current and a 1.5 kW motor at 400 V. The thermal overload release follows a Class 10 trip curve, meaning it will trip within 10 seconds at 7.2× rated current — fast enough to protect standard induction motors during a stall or locked-rotor condition without nuisance tripping on normal starting inrush. The magnetic short-circuit trip (instantaneous) handles fault clearing, with a breaking capacity of 100 kA at 240 V AC and 400 V AC, dropping to 3 kA at 500 V and 2 kA at 690 V — that 100 kA figure means this breaker can interrupt a bolted fault on a high-capacity transformer secondary without upstream fuses needing to clear first, as long as the available fault current at its mounting point stays under that rating. Phase failure detection is built in — if one phase drops out on a three-phase motor, the thermal element sees the resulting current imbalance and trips the breaker, preventing single-phasing damage.
Mounting and wiring
Mounts on 35 mm DIN rail per EN 50022, either snapped on or screwed, in any orientation — no derating needed for side-by-side stacking (0 mm clearance required at the sides and rear). Dimensions are 45 mm wide × 90 mm tall × 81 mm deep — that 81 mm depth matters when you're laying out a shallow enclosure; it's the same depth as the standard SIRIUS contactor it pairs with, so the busbar links line up without a step. Main circuit terminals accept 2× (0.5…1.5 mm²) solid or 2× (0.75…2.5 mm²) stranded, or 2× (18…14 AWG) — screw-type terminals, not spring-cage, so factor in the screwdriver time if your panel shop is used to push-in connectors. Auxiliary and control circuit terminals are also screw-type; the auxiliary switch is a transverse design, which means the contact block mounts on the side of the breaker rather than the front, keeping the overall depth unchanged.
Environmental and compliance
Operating temperature range is -50 to +60 °C; storage and transport range is -50 to +80 °C — wide enough for unheated warehouses or outdoor cabinet installations in temperate climates. Shock rated at 25 g for 11 ms — suitable for mounting on machinery that sees vibration from conveyors or presses. Front-face protection is IP20 — finger-safe from the front but not sealed against dust or moisture; install inside a panel with a door.