Motor protection circuit breaker for 35 mm DIN rail
Rated operational voltage spans 20 to 690 V AC, with a maximum AC-3 switching frequency of 15 operations per hour.
The 3RV2021-4NA20-0BA0 carries a rated ultimate short-circuit breaking capacity (Icu) of 10 kA at 400 V AC, 5 kA at 500 V AC, and 2 kA at 690 V AC. For coordination with an upstream MCCB or fuse, the conditional short-circuit current (Ics) is higher: 25 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC — these are the values used when the breaker is backed by a gG 63 A fuse (the evidence lists gG 63 A at 400 V, 500 V, and 690 V). This means the breaker can be installed downstream of a 63 A gG fuse and still clear a fault up to 25 kA at 400 V without the fuse needing to open.
Clearance requirements: 50 mm upwards, 50 mm downwards, 30 mm to the side, and 0 mm forwards/backwards — so it can be panel-mounted flush against the backplane. The S0 frame size (45 mm width, 97 mm depth, 119 mm height) is the standard footprint for this class of Siemens motor-protective device.