Transformer-protection breaker, Trip Class 10
The Siemens SIRIUS 3RV2411-1FA20 is a circuit breaker designed specifically for transformer protection, with a Trip Class 10 thermal-magnetic characteristic that clears overloads within 10 seconds at 7.2× rated current — a tight curve that keeps inrush from nuisance-tripping while still protecting the transformer winding from sustained overloads. It mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715, in any orientation, and uses spring-loaded terminals on the main current circuit — 2× (0.5 to 4 mm²) solid or stranded — so panel wiring is tool-less and vibration-resistant. The 45 mm width (3 TE) and 97 mm depth fit standard distribution boards and motor starter combos; the 106 mm height leaves clearance under typical 200 mm enclosure depths.
Rated breaking capacity hits 100 kA at 240 V, 400 V, and 500 V, dropping to 4 kA at 690 V — this is a high-fault-rated device for industrial panels where upstream transformers can deliver substantial short-circuit current. Backup fuse coordination is specified: gL/gG 32 A at 400 V and 500 V, stepping down to gL/gG 25 A at 690 V. That means the breaker and fuse share the fault energy predictably — no cascade failures downstream.