SIRIUS circuit breaker for system protection
The Siemens SIRIUS 3RV2021-1EA10-0DA0 is a circuit breaker designed for system protection in motor branch circuits and distribution panels. The Size S0 frame takes up 45 mm width on the rail, with 97 mm depth and height. For a panel OEM, that 45 mm per pole is the critical fill factor — three of these on a rail eat 135 mm before you add any auxiliary contact block or shunt trip.
Breaking capacity and voltage limits
The 100 kA rating at 240 V and 400 V AC holds across the 500 V level as well, then drops sharply to 4 kA at 690 V. The AC-3e maximum switching rate is 15 operations per hour — this is not a high-cycling application breaker; it is sized for motor starts and occasional fault interruption, not for frequent load switching. Rated operational voltage spans 20 to 690 V, covering most low-voltage industrial systems. The 0.8 kW motor rating at 230 V gives a rough sizing anchor for smaller loads; for 400 V systems, match the motor FLA to the breaker's thermal setting range (not listed here, but standard for the SIRIUS 3RV2 family).
Main circuit terminals are screw-type, accepting 2x 1 to 2.5 mm² or 2x 2.5 to 10 mm² solid or stranded copper. The screwdriver shaft diameter is 5 to 6 mm, tip Pozidriv size 2. Main contact terminal thread is M4. Clearance: 50 mm upwards and downwards, 30 mm at the sides, zero forwards and backwards (–). That zero forwards/backwards clearance means the breaker can be butted directly against the back panel and adjacent devices on the same DIN rail — no breathing gap needed.