The Siemens SIRIUS 3RV2411-0AA15 is a circuit breaker designed specifically for transformer protection, not general motor or feeder duty. That means its trip curve and thermal memory are tuned to handle the inrush and magnetizing current of a transformer without nuisance tripping, while still clearing a winding fault fast. Rated breaking capacity hits 100 kA at 400 V AC — that's the fault current it can safely interrupt without welding contacts or venting arc plasma into the panel. It carries a CLASS 10 trip characteristic, so it will open within 10 seconds at 600% of the thermal setting, which is standard for protecting transformers against sustained overloads.
Mounting and integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. The 45 mm width (three module spaces) and 97 mm depth fit a standard distribution board or control panel without overhang. Any mounting position is allowed, so you can orient it vertically or horizontally in a tight gland plate layout. Terminals accept 2x (0.5 to 1.5 mm²) solid or stranded, or 2x (0.75 to 2.5 mm²) — sized for the control transformer primary side wiring typical in MCC buckets.
Key ratings and what they mean
Phase failure detection is built in — if one phase drops out on the primary side, the breaker trips, preventing single-phasing damage to the transformer. The rated insulation voltage spans 20 to 690 V, covering most low-voltage distribution systems up to 690 V line-to-line. Ambient operating range is -20 to +60 °C, with storage from -50 to +80 °C, so it handles unheated warehouses and panel heat rise without derating.