Siemens 3RV1421-1EA10 Motor Protection Circuit Breaker

Siemens 3RV1421-1EA10 is a three-pole motor protection circuit breaker (MPCB) from the SIRIUS family, sized for DIN-rail mounting and rated for up to 690 V AC. It provides adjustable overload protection with an A-release setting spanning 2.8 to 4 A, making it suitable for protecting small to mid-size motors in control panels. The device is IP20 protected on the front, with screw-terminal connections for straightforward wiring. Electrical ratings include insulation up to 690 V, impulse withstand of 6,000 V, and a continuous current rating of 4 A. Designed for motor protection, it combines thermal overload protection with magnetic short‑circuit protection in a compact 3‑pole package. The MPCB tolerates ambient operating temperatures from -20 to +70 C and installation elevations up to 2,000 m, with a mechanical operating life around 100,000 switching cycles and typical power loss of about 6 W. Its DIN-rail footprint and robust build make it a common choice for reliable motor protection in industrial automation panels.