Transformer-protection circuit breaker, size S00
The Siemens SIRIUS 3RV2411-1HA20-0DA0 is a size S00 circuit breaker designed specifically for transformer protection. It carries a Trip Class 10, meaning it trips within 10 seconds at 7.2× the thermal setting — fast enough to limit transformer inrush stress without nuisance tripping on magnetizing current. Breaking capacity is 100 kA at 400 V AC, which covers most industrial secondary-side faults. The rated voltage range spans 20 to 690 V, so it can be used on 400 V, 500 V, or 690 V transformer primaries with appropriate gG fuse backup coordination. Mounting is via screw and snap-on onto 35 mm DIN rail per DIN EN 60715. The spring-loaded terminals on the main current circuit accept 2× (0.5 to 4 mm²) solid or stranded conductors. Clearance requirements: 50 mm upwards, 0 mm forwards, 0 mm backwards, 50 mm downwards, and 30 mm at the side. The 45 mm width and 97 mm depth fit standard S00 panel cutouts.
Breaking capacity and fuse coordination
The 3RV2411-1HA20-0DA0 delivers 100 kA at 240 V AC and 100 kA at 400 V AC. At 500 V AC it drops to 42 kA, and at 690 V AC to 4 kA. For transformer protection, the manufacturer specifies gG fuse backup values: 50 A at 400 V, 40 A at 500 V, and 35 A at 690 V. Those fuse ratings are the maximum upstream gG fuse that still allows the breaker to clear its rated fault current — coordination per IEC 60947-2.
Environmental and operating limits
Operating temperature range is -20 to +60 °C; storage and transport range is -50 to +80 °C. The maximum switching rate at AC-3 duty is 15 operations per hour, and the same limit applies for AC-3e. Mounting position is any. The screwdriver shaft diameter is 3 mm, tip size 3.0 × 0.5 mm.