The Siemens 3RV2811-1HD10 is a SIRIUS circuit breaker in frame size S00, designed specifically for transformer protection in accordance with UL 489 and CSA C22.2 No.5. The key spec that defines its real-world fit is the breaking capacity: 100 kA at 400 V AC (and at 240 V AC), 42 kA at 500 V AC, and 6 kA at 690 V AC.
Transformer protection design and coordination
This breaker is purpose-built for transformer protection, not general motor or feeder duty. The design per UL 489 means it handles the magnetizing inrush of a transformer without nuisance tripping, while still providing short-circuit and overload protection for the transformer and its secondary-side conductors. The rated operational voltage range is 20 to 690 V, covering most low-voltage transformer primaries. For selectivity and fuse coordination, the maximum permissible backup fuse ratings are specified per voltage: gG 50 A at 400 V, gG 40 A at 500 V, and gG 35 A at 690 V. This is critical for an engineer designing a coordinated protection scheme — the upstream fuse must not exceed these values to ensure the breaker clears a fault within its rated capacity.
Dimensions are 97 mm deep, 45 mm wide, and 144 mm tall. Clearance requirements: 70 mm upwards and downwards, 30 mm to the side, and zero forwards or backwards — so it can be mounted flush against a back panel or enclosure wall. The main contact screw is M4, requiring a Pozidriv size 2 screwdriver tip with a shaft diameter of 5 to 6 mm. These are standard panel-building details — no special tooling needed.