The Siemens 5SY7125-8 is a 1-pole SENTRON miniature circuit breaker from the 5SY7 design, rated 25 A with a D tripping characteristic. It breaks fault currents up to 15 kA per EN 60898 and 25 kA per IEC 60947-2 at 400 V AC, with a DC rating of 15 kA per IEC 60947-2 at 72 V DC. The D curve means it tolerates high inrush currents — typical for motor, transformer, or welding loads where the start-up spike would nuisance-trip a B or C curve. For UL-marked panels, it carries a 5 kA interrupting rating per UL 1077 and CSA C22.2 No.235.
Integration & mounting
Snaps onto DIN rail via the quick assembly system; occupies 1 width unit (18 mm). Mounting position is any, so it fits horizontal busbar layouts or vertical sub-distribution boards without derating. Installation depth is 70 mm, overall depth 76 mm — leaves clearance for a standard 80 mm deep enclosure backplate. Terminals accept solid or stranded conductors from 0.75 up to 35 mm², with combined top and bottom terminals for daisy-chaining or feed-through wiring. IP20 with connected conductors; touch protection is built in.
Sourcing posture
This is an active, in-production line item. Sourced and quoted to order against an RFQ through independent distribution channels; availability and current pricing confirmed at quote time. No last-time-buy or phase-out notice applies.