The Siemens 5SJ4225-8HG41 is a SENTRON 5SJ4 miniature circuit breaker with a D tripping characteristic, rated 25 A at 30 °C and 40 °C, and 10 kA breaking capacity per EN 60898. The D-curve means it tolerates the high inrush currents typical of motor loads, transformers, and welding equipment — where the short-circuit trip threshold is 10 to 20 times rated current — without nuisance tripping on startup.
Thermal derating and ambient limits
Rated 25 A at 30 °C and 40 °C, the breaker derates to 24.3 A at 45 °C, 23.8 A at 50 °C, 23.1 A at 55 °C, and 22.5 A at 60 °C. If the panel ambient runs above 40 °C, size the branch circuit for the derated value, not the nameplate 25 A. The unit operates from -40 °C to 75 °C ambient, covering unheated enclosures and high-heat machine cabinets.
Sourcing posture
This 2-pole D-curve 25 A MCB is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time. For a BOM line or a line-down replacement, submit an RFQ with your target quantity and delivery window.