The Siemens 3RV1011-1FA10-ZW95 is a SIRIUS motor protection circuit breaker — the part that sits between the contactor and the motor in a standard starter assembly. It's sized for a 45 mm DIN-rail footprint and screws or snaps onto 35 mm rail per DIN EN 60715. The key number for the panel builder is the 100 kA SCCR at both 240 V and 400 V: that's the fault current this breaker can safely interrupt without welding its contacts or venting plasma into the enclosure. For a 480 V or 600 V line, the interrupting rating drops to 5 A — so this is a 400 V-class device, not a 600 V general-purpose breaker.
Trip curve and motor protection
Trip Class 10 disconnects within 10 seconds at the thermal setting. Phase failure detection is included. No ground fault detection. Rated voltage is 20 to 690 V; at 690 V the interrupting capacity is 2 kA.
Mounting and wiring
Mounts in any position — no derating for sideways or upside-down install, which helps in tight gland-plate layouts. Screw-type terminals on the main circuit accept 2×(0.5 to 1.5 mm²) or 2×(0.75 to 2.5 mm²) solid or stranded. The M3 terminal screws are standard for this frame size. Clearance: 20 mm upwards and downwards, 9 mm at the sides, zero forwards and backwards. That 20 mm top clearance is the one to watch — if the panel lid has a gland plate or busbar shroud, measure before you commit the layout.