What this MCCB carries and where it fits
The Siemens 3VA1125-5EF36-0AH0 is a 3-pole SENTRON molded case circuit breaker rated for a continuous current Iu of 25 A, with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V — numbers that put it squarely in high-fault-duty distribution panels where a standard MCB would weld shut. The 800 V rated insulation voltage (Ui) tells you this breaker is built for 690 V line-to-line systems, not just 480 V panels. IP40 on the front means it keeps tools and fingers out but won't survive a washdown; mount it inside a glanded enclosure.
Thermal derating and the TM240 release
The TM240 release holds 25 A from 40 °C up to 50 °C with no derating. At 55 °C it drops to 24 A, at 60 °C to 23.5 A, at 65 °C to 23 A, and at 70 °C to 22.5 A. That's a flat curve through the first 10 °C above ambient — useful if the breaker sits in a crowded panel with other heat sources. The thermal adjustment (tr max.) is set at 1 s, which means short-circuit protection trips fast enough to protect downstream cable in a coordinated distribution scheme.
Auxiliary contacts and lifecycle
This breaker ships with 2 auxiliary switches plus 1 trip alarm switch (HQ version). No undervoltage release, no shunt trip, no ground-fault module, no communication function — it's a clean line-protection device for a feeder or a large motor branch circuit. The latching endurance is rated at 15 000 operations, which is typical for a molded-case breaker in a panel that sees occasional switching, not daily cycling. The operating temperature range (-25 °C to 70 °C) and storage range (-40 °C to 80 °C) mean it survives a nacelle winter or a desert substation equally well.