Siemens 3RV2021-4AA25 Motor Protection Circuit Breaker

Siemens 3RV2021-4AA25 is a three‑pole Sirius motor protection circuit breaker (size S0) designed for motor protection in 3‑phase circuits. It combines thermal overload protection (A‑release) with a short‑circuit release (N‑release) and provides a built‑in auxiliary contact pair (1 normally open + 1 normally closed) for signaling, with spring‑type terminals for both main and auxiliary circuits. The A‑release is adjustable from 10 to 16 A, while the N‑release is rated to 208 A, delivering robust protection against both overload and short circuits. It features standard switching capacity with transverse auxiliary switching, and its insulation rating extends to a maximum of 690 V, making it suitable for typical industrial motor circuits up to that voltage, with a short‑circuit breaking capacity cited up to 65 kA at 480 V. The unit is rated for ambient temperatures from −20 to 60 °C and is part of the Sirius 3RV2 family, commonly used in motor control panels where compact, code‑compliant motor protection and a visible disconnect are required.