What the ratings mean for fit
The Siemens 3VA1125-4EF32-0JC0 is a 3-pole SENTRON molded case circuit breaker rated 25 A continuous at 40 °C, with full thermal current up to 50 °C before derating begins at 55 °C (24 A) and 65 °C (23 A). That means it holds its full rating across typical North American and European panel ambient conditions — no headroom lost until the enclosure runs hot. Interrupting capacity is 121 kA at 240 V, 75.6 kA at 415 V, and still 11.9 kA at 690 V. For a 25 A frame, those numbers are high — this breaker coordinates cleanly downstream of a larger upstream device without needing a current-limiting fuse ahead of it in most industrial distributions. Rated insulation voltage is 800 V, so it's rated for 690 V line-to-line systems common in European and Canadian industrial plants. The 70 mm depth and 76.2 mm width fit standard Siemens 3VA panel cutouts and DIN-rail adapters — no rework to drop it into an existing SENTRON lineup.
Line protection design — what it does and doesn't do
This breaker is designed for line protection — meaning it protects cables and busbars against overload and short circuit, not motors or generators. It ships with a shunt trip (STL) auxiliary release for remote tripping and two auxiliary switches (HQ) for status feedback to a PLC or indicator lamp. No undervoltage release, no ground-fault monitoring, no communication module — this is a straightforward thermal-magnetic MCCB for distribution panels where remote trip and contact status are the only extras needed.
Lifecycle and sourcing reality
Maximum power loss is 8.5 W, so thermal management in a dense panel is straightforward — no forced cooling required for this single breaker.
Panel integration notes
Mounts on DIN rail or direct panel. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C. The 70 mm depth leaves clearance for standard 80 mm deep enclosures with wiring gutters. No trip indicator on the front face — status is read from the handle position or the auxiliary switches.