Siemens 3RV2021-4DA10 SIRIUS 3RV2 25A 55kA Motor Starter Protector Circuit Breaker Size S0

The Siemens 3RV2021-4DA10 is a SIRIUS 3RV2 series motor starter protector (circuit breaker) rated 20–25 A with a 55 kA breaking capacity in Size S0. It combines thermal overload and short-circuit protection in a single device, making it a direct fit for motor branch circuit protection in IEC control panel assemblies without a separate overload relay.

Technical Specifications

Certifications & Standards

• cULus
• UL

Applications & Use Cases

The 3RV2021-4DA10 is sized for three-phase motor loads up to 25 A — typically 7.5–11 kW at 400 V. The 55 kA breaking capacity at rated voltage covers the fault levels encountered in low-impedance industrial distribution systems without requiring upstream current-limiting fuses for coordination. Size S0 frames mount directly on standard DIN rails and accept the full range of SIRIUS 3RV2 accessories: auxiliary contacts, shunt trips, and undervoltage releases. Installations requiring UL 508 panel certification benefit from the cULus listing, which validates both the motor branch circuit and the motor controller application in North American markets.