The Siemens 3RV1021-1FA15-ZX95 is a SIRIUS motor protection circuit breaker rated for 5 A continuous current with a Class 10 trip characteristic, designed to protect motors against overload and short-circuit in industrial control panels. It snaps onto a 35 mm DIN rail per EN 50022 and takes up 45 mm of panel width — a standard two-module footprint for this class of breaker. The 100 kA breaking capacity at 400 V AC means this breaker can safely interrupt a bolted fault at the motor terminals without requiring an upstream current-limiting fuse for most installations — the full rated SCCR is available at the load side.
Motor protection and trip behaviour
Class 10 trip ensures the breaker opens within 10 seconds at 7.2× the thermal setting, matching the standard protection curve for standard induction motors during a locked-rotor event. Phase failure detection is built in — if one phase drops out, the breaker trips faster than a standard three-pole thermal, preventing single-phasing damage on delta-connected motors. At 400 V the breaker is rated for a 1.5 kW motor; the same unit covers smaller loads down to the minimum setting of the adjustable thermal element.
Breaking capacity across the voltage range
Rated short-circuit breaking capacity holds at 100 kA up to 500 V AC, dropping to 6 kA at 690 V AC — the voltage-dependent derating is typical for air-break contactors and MCCBs in this frame size.
Termination and wiring
Screw-type terminals on the main circuit accept 2x (0.5…1.5 mm²) solid or 2x (1…2.5 mm²) stranded — common for panel wiring with ferrule or direct termination. Auxiliary contacts are transverse design; the breaker ships with an auxiliary switch block fitted (0 built-in auxiliary contacts on the base unit, so the switch is an add-on module).
Environmental limits and mounting
Rated for -20 to +60 °C operating ambient, storage down to -50 °C, with shock resistance of 25 g / 11 ms — suitable for machine-mounted panels on presses or conveyors. IP20 on the front face means finger-safe against accidental contact; the breaker is intended for installation inside an enclosure with a higher overall IP rating. Mountable in any position, with zero clearance required at the sides or rear — no derating needed for tight panel layouts.