The Siemens SIRIUS 3RV2011-0JA15-ZX95 is a motor protection circuit breaker — the part that sits between the contactor and the motor, sized to protect the windings from overload and short-circuit. It is a current-production part, still in the catalog as an active line item. Trip Class 10 means it will trip within 10 seconds at 7.2× the thermal setting — fast enough to protect standard induction motors during a locked-rotor event, but not so aggressive that it nuisance-trips on normal starting inrush. The 100 kA breaking capacity at 400 V (also at 240 V, 500 V, and 690 V) means this breaker can safely interrupt a bolted fault on a high-capacity distribution bus without welding its contacts or venting arc gas into the panel. Phase failure detection is built in — if one phase drops out, the breaker trips before the motor single-phases to a smoking stop. No ground-fault detection on this variant, so if you need GF protection, you add an external module or choose a different suffix.
Panel fit and mounting
Mounts via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width (3 module spaces) is standard for this current range. Depth is 97 mm, height 97 mm — it does not overhang a standard 100 mm deep enclosure backplate. Mounting position is any, so you can lay it sideways in a shallow gland-top panel if needed. Clearance: 50 mm above and below, 30 mm to the side for arc-chamber venting and heat dissipation. Zero clearance forward — the breaker face can sit flush against a door or cover.
Termination and wiring
Main circuit terminals are M3 screw-type. Wire capacity: 2× (0.5 to 1.5 mm²) or 2× (0.75 to 2.5 mm²) solid or stranded. That covers most panel-building practice for motor circuits up to this size — no need for ferrules on stranded if you strip clean, but ferruled ends seat better in the cage.
Operating conditions and ratings
Runs from -20 to +60 °C ambient; stores and ships from -50 to +80 °C. The voltage range across the main contacts is 20 to 690 V — covers everything from 24 V control transformers up to 690 V industrial mains. Auxiliary contact ratings: 1 A at 24 V, 0.5 A at 120/125/230 V, 0.15 A at 60 V. Maximum switching rate in AC-3 duty is 15 operations per hour. Rated motor power at 230 V is 0.2 kW — that is the smallest motor this breaker can protect on a 230 V line. The 100 kA SCCR at 400 V and 690 V means it is rated for installation on high-fault-current panels without requiring upstream current-limiting fuses.