Transformer protection circuit breaker — 1.6 A, 100 kA, CLASS 10
The Siemens SIRIUS 3RV1421-1AA10 is a 3-pole circuit breaker designed specifically for transformer protection, rated at 1.6 A continuous current with a 100 kA breaking capacity across the full voltage range up to 690 V AC. That 100 kA holds at 240 V, 400 V, 500 V, and 690 V — no derating as voltage climbs, which is unusual for a breaker this compact. The 45 mm width (3-module) footprint fits standard panel layouts. Screw-type terminals on both main and auxiliary circuits accept solid or stranded copper up to 6 mm² (2x 1–2.5 mm² or 2x 2.5–6 mm² per terminal).
Protection features and ratings
Ground fault detection is not included; that would require an external module. Power dissipation is 7.25 W total hot (2.4 W per pole), which is modest for a 1.6 A breaker — panel thermal budgeting is straightforward. The IP20 front protection and finger-safe touch protection (per the evidence) mean the front face is safe for operator access in a closed panel. Shock resistance is rated at 25g for 11 ms, and the operating temperature range is -20 to +60 °C, with storage/transport from -50 to +80 °C. The auxiliary switch extension option (product extension auxiliary switch = Yes) allows remote status indication.
The substance prohibitance date of 01.05.2012 indicates RoHS compliance. The SIRIUS series carries CE marking as standard for the European market.