Siemens SENTRON 3VA1225-5EF32-0CA0 — 250 A MCCB with TM240 release
The Siemens SENTRON 3VA1225-5EF32-0CA0 is a 3-pole molded case circuit breaker rated for 250 A continuous current (Iu) at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release. It carries a breaking capacity of 187 kA at 240 V AC and 121 kA at 415 V AC — figures that place it in the high-interrupting category for industrial distribution panels where fault currents exceed typical 50–65 kA ranges. The 70 mm depth and 105 mm width fit standard SENTRON mounting footprints, so it swaps into existing 3VA panel layouts without re-drilling the backplate. This is the line protection version, meaning it is configured for feeder and main breaker duty rather than motor branch-circuit protection. The TM240 release provides fixed thermal and magnetic trip settings — no interchangeable rating plugs — so the 250 A frame is the only continuous-current option for this order code. An undervoltage release (UVR) is integrated; the auxiliary trip accessory is order code 3VA9608-0BB24. There is no auxiliary contact, no communication module, and no ground-fault monitoring on this variant.
Breaking capacity and thermal derating
The interrupting ratings span four voltage levels: 187 kA at 240 V, 121 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V (–). At 415 V, 121 kA exceeds the typical 50–65 kA SCCR found in most North American panel schedules — this breaker is sized for high-fault installations such as transformer secondaries or large motor control centers where the available fault current is known to be above 100 kA. The rated insulation voltage (Ui) is 800 V, confirming the 690 V rating is within the device's insulation coordination. Thermal derating begins at 55 °C: the breaker carries the full 250 A up to 50 °C (–), then steps down to 243.3 A at 55 °C, 236.5 A at 60 °C, 229 A at 65 °C, and 223 A at 70 °C (–). The operating ambient range is -25 °C to +70 °C (–); storage range is -40 °C to +80 °C (–). For a panel that runs at 60 °C internal ambient, the usable current is 236.5 A — a 5.4 % reduction from the nameplate rating.
Panel integration and mechanical notes
The breaker measures 105 mm wide, 158 mm high, and 70 mm deep (–). It mounts on a DIN rail or directly to a backplate via the SENTRON mounting base. The front face carries an IP40 protection class, suitable for enclosed panel installation where no water spray is present. Latching endurance is rated at 15,000 cycles — sufficient for main breaker duty where switching events are infrequent. There is no trip indicator on the front, so a remote indication requires the auxiliary contact accessory (not included).