What this MCCB is and what the ratings mean for fit
The Siemens 3VA1125-6ED42-0AA0 is a 4-pole SENTRON molded case circuit breaker (MCCB) rated 25 A continuous at 40 °C, built for line protection in distribution panels and motor branch circuits. The TM210 thermal-magnetic trip unit gives fixed thermal and magnetic pickup — no adjustment dials, which simplifies spec-in for a standard feeder and removes a calibration variable on the line. Breaking capacity is the headline: 220 kA at 240 VAC, 154 kA at 415 V, 121 kA at 440 V, and still 17 kA at 690 V. That 220 kA at 240 V means this breaker handles extremely high available fault current — typical for transformer secondaries or large UPS outputs — without needing a current-limiting fuse upstream. At 690 V the 17 kA rating is still adequate for most industrial motor control centers. Current derating is published across the full operating range: full 25 A up to 50 °C, then 24 A at 55–60 °C, and 23 A at 65–70 °C. If the panel ambient runs hot — say a non-ventilated enclosure near a furnace line — factor that 2 A drop at 65 °C into the load calculation. The 70 mm depth and 101.6 mm width fit standard Siemens 3VA panel footprints and DIN-rail adapters.
Integration notes for the panel builder
Front IP40 protection means it is splash-resistant from the front but not sealed for washdown — install inside a panel with at least IP54 enclosure if the environment is wet. The 4-pole construction covers three-phase plus neutral switching, common for European-style distribution where the neutral is switched with the phases. No undervoltage release or shunt trip fitted on this variant; if remote tripping is needed, order the accessory version or add a separate UVR module. Power loss is 8.5 W maximum at rated load — negligible for thermal budgeting in a standard enclosure, but worth noting if the panel packs many breakers in a sealed box. Storage temperature range of -40 to 80 °C covers warehouse extremes; operating range is -25 to 70 °C.