What it is and what it does
The Siemens 3RV1011-0FA25 is a SIRIUS motor protection circuit breaker rated for 0.5 A continuous current with a Class 10 trip characteristic, meaning it protects motor circuits against overload and short-circuit while allowing starting inrush up to about 10 seconds before tripping. It breaks up to 100 kA at 400 V AC, which covers most industrial panel fault levels without needing an upstream current-limiting fuse. Phase failure detection is built in — if one line drops, the breaker trips faster than a standard thermal overload, preventing single-phasing damage to the motor. It does not include ground fault detection, so if that's required, plan for a separate GF module or residual current device downstream.
Mounting and wiring — zero-clearance fit
Snaps onto 35 mm DIN rail per EN 50022, and the zero-clearance design (0 mm backwards, 0 mm at the side) means you can pack breakers tight on the rail without worrying about heat buildup from adjacent units. Mounting position is any orientation, which helps in tight enclosures where vertical rail space is limited. Both the main circuit and auxiliary/control connections use spring-loaded terminals accepting 0.25 to 2.5 mm² solid or 24 to 14 AWG stranded. No screw torque to verify — just strip 8–10 mm, push in, done. The auxiliary switch is transverse-mounted and can be extended with additional contact blocks if the built-in 1 A at 24 V or 0.5 A at 230 V contact ratings aren't enough for your PLC input draw.
Breaking capacity — what 100 kA really means
The 100 kA breaking capacity holds across the full voltage range from 240 V to 690 V AC. That's a rare flat curve — most breakers derate as voltage rises. Here, you get the same 100 kA at 690 V that you get at 240 V, so it handles high-fault industrial supplies without needing a coordination study for the upstream breaker. With a rated insulation voltage of 690 V and surge voltage resistance of 6 kV, the breaker is comfortable on 400 V and 480 V systems with margin. The AC-3 switching capacity is rated for motors up to 0.12 kW at 400 V, which aligns with the 0.5 A continuous setting — this is sized for small drives, pumps, or fan motors in that power band.