The Siemens SENTRON 5SJ6125-7 is a 1-pole miniature circuit breaker (MCB) from the 5SJ6 series, rated at 25 A with a C tripping characteristic. It breaks fault currents up to 6 kA per EN 60898 and IEC 60947-2, which is the standard interrupting rating for commercial and light industrial distribution boards — adequate for most sub-distribution panels where the upstream transformer impedance keeps prospective fault current below that level.
The 25 A rating at 240 V AC covers a single-phase branch circuit; the 6 kA breaking capacity means it can safely clear a short-circuit fault up to that level without welding contacts or venting arc gas into the enclosure. The 1-pole, 1-width-unit form factor snaps onto a standard DIN rail and occupies 18 mm of panel width — leaves room for adjacent breakers in a multi-pole assembly. Conductor termination accepts solid or stranded copper from 0.75 to 25 mm², which covers most branch-circuit wire sizes from 18 AWG up to 4 AWG. The IP20 rating is standard for enclosed panel-mount devices — touch-safe only when conductors are connected; not rated for wet or outdoor locations without an additional enclosure.
Deployment context
Installation depth is 70 mm, which fits typical 100 mm deep enclosures with clearance for wiring.