What it is and what it does
The Siemens 3RV1011-1KA10-ZX95 is a SIRIUS motor protection circuit breaker, designed specifically for protecting three-phase induction motors against overload, short-circuit, and phase failure. A CLASS 10 trip characteristic means it will disconnect within 10 seconds at 7.2× the thermal setting, matching the startup profile of standard squirrel-cage rotors — no nuisance tripping on inrush, but fast enough to keep the winding from cooking on a locked rotor. Phase failure detection is built in, so a lost leg on a conveyor or crusher motor won't run single-phase and burn the winding before the overload curve catches it.
Where it fits — panel and pit
Mounts via screw and snap-on onto 35 mm standard mounting rail per DIN EN 60715. The 45 mm width is a single modular unit — it occupies one 45 mm slot on the rail, leaving the adjacent space for contactors or auxiliaries. Depth of 75 mm and height of 90 mm keep it within standard 200 mm deep enclosures. Any mounting position is allowed, so you can lay it sideways in a shallow gland plate if needed. Clearance requirements: 20 mm upward and downward, 9 mm to the side, zero forward and backward. The screw-type terminals for the main current circuit accept 2x (0.5... 1.5 mm²) solid or stranded, or 2x (0.75... 2.5 mm²) — M3 screws for the main contacts.
Breaking capacity — what it can interrupt
Short-circuit breaking capacity varies with line voltage, and this breaker is rated for the full range: 100 kA at 240 V, 13 kA at 400 V, 3 kA at 500 V, and 2 kA at 690 V. That 100 kA at 240 V means it can sit downstream of a transformer with very high fault current without needing a current-limiting fuse upstream — useful in plant distribution where the available fault current at the panel is high. The backup fuse ratings for gL/gG fuses are 80 A at 240 V and 400 V, stepping down to 50 A at 500 V and 690 V.