The Siemens 5SJ4302-7HG42 is a 3-pole miniature circuit breaker from the SENTRON 5SJ4 series, rated 2 A at 400 V AC with a C tripping characteristic. At 30 °C and 40 °C it holds the full 2 A; derate to 1.9 A at 45 °C and 50 °C, and 1.8 A at 55 °C and 60 °C, which matters if the breaker sits inside a warm enclosure. It snaps onto a standard mounting rail in any position, so panel layout is flexible.
Mounts on a standard mounting rail (DIN rail) — fastening method is snap-on, no tools needed for the rail. IP20 with connected conductors, IP40 in the handle range; suitable for enclosed panels, not for washdown environments.