The Siemens 3RV1011-0KA20-ZX95 is a SIRIUS motor protection circuit breaker sized for a 0.37 kW motor at 400 V. It carries a 1.25 A continuous current rating and a Class 10 trip characteristic, meaning it will ride through normal motor startup but trip fast enough to protect the winding against a locked rotor. Breaking capacity is 100 kA at 400 V AC — that's full-rated fault interruption without needing an upstream fuse for most industrial service entrances.
Panel fit and mounting
Mounts on 35 mm DIN rail per EN 50022 via screw or snap-on. The 45 mm width and 90 mm height are standard for the SIRIUS 3RV1 frame, so it occupies one 45 mm slot in a panel layout. Depth is 81 mm from the rail face — check gland plate clearance if the enclosure is shallow. Spring-loaded terminals on the main circuit accept 2x (0.25... 2.5 mm²) solid or 2x (0.25... 1.5 mm²) finely stranded with ferrule. No backwards or side clearance needed; IP20 on the front.
Protection and auxiliary features
Phase failure detection is built in — the breaker will trip on loss of any phase, preventing single-phasing damage. Ground fault detection is not included. An auxiliary switch is present (1 NO/NC set typically), which can report trip status back to a PLC or annunciator. Mechanical endurance is 100,000 operations on the main contacts. Maximum switching rate in AC-3 duty is 15 operations per hour.
Environmental and electrical ratings
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. Altitude limit is 2,000 m without derating. Shock resistance is 25 g for 11 ms. Surge voltage withstand is 6 kV. Power dissipation at rated current in hot state is 5.5 W total, 1.8 W per pole.