125 A, 4-pole B-curve MCB — what the ratings mean
The Siemens SENTRON 5SP4492-6 is a 4-pole miniature circuit breaker with a B tripping characteristic, rated 125 A at 400 V AC with a 10 kA breaking capacity per EN 60898. The B-curve means it trips between 3 and 5 times rated current — suited for resistive and general-purpose loads where inrush isn't severe. At 125 A per pole this covers heavy branch circuits like large lighting banks, distribution sub-feeds, or resistive heating loads. The 10 kA SCCR at 400 V AC tells you it safely interrupts a fault current up to that level without welding contacts or cascading upstream — critical for panel coordination studies.
Mounting and panel fit
Snaps onto DIN rail or accepts screw fixing, so it integrates into standard distribution boards or industrial enclosures. At 6 modular width units (108 mm wide) and 70 mm installation depth, it occupies the same footprint as other 4-pole 125 A SENTRON breakers — no surprise when swapping into an existing panel layout. Mounting position is unrestricted, which simplifies layout in tight cabinets.
Environmental and compliance notes
Halogen-free and silicon-free construction, rated for pollution degree 3 and overvoltage category III. IP20 with connected conductors; IP40 at the handle area with a distribution cover. The -40 °C to +75 °C operating range covers outdoor enclosures in cold climates. Sealable design allows lockout-tagout for isolation procedures.