SENTRON 3VM1 — 25 A MCCB with 320 A Frame, TM210 Trip
The Siemens 3VM1025-4ED32-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for line-protection duty, carrying a continuous current of 25 A at 40 °C ambient on a 320 A frame size — meaning the thermal-magnetic trip unit (TM210) governs the load current while the frame provides headroom for high-fault interruption without mechanical stress on the mechanism. Three-pole construction, rated insulation voltage of 800 V, and interrupting capacity that scales with system voltage: 121 kA at 240 V, 76 kA at 415 V, 40 kA at 440 V, and 12 kA at 500 V — a curve that tells you this breaker is sized for low-voltage distribution where the available fault current is highest at the transformer secondary and drops as you move downstream. The TM210 designation indicates a fixed thermal-magnetic trip with a 10× rated-current magnetic pickup, typical for feeder and branch-circuit protection in panelboards and motor control centers where coordination with downstream devices matters more than adjustable instantaneous settings.
Thermal Derating and Power Dissipation
Rated current holds flat at 25 A from 40 °C through 50 °C, then begins a gentle derating: 24 A at 55 °C and 60 °C, 23 A at 65 °C and 70 °C — a curve that matters when the breaker is packed into a high-density panel where internal ambient can push past 50 °C without forced ventilation. Maximum power loss is 9 W at rated load — a figure that feeds into the panel thermal budget, especially when multiple breakers share a common enclosure and the cumulative heat drives the derating calculation.
Width 76.2 mm (3 in), depth 70 mm (2.76 in), height 130 mm (5.12 in) — a 3-pole MCCB footprint that fits standard Siemens SENTRON mounting bases and busbar systems; the 70 mm depth is shallow enough for 200 mm deep enclosures without crowding the gland plate.