What this MCCB carries
The Siemens 3VA1225-4EF32-0BA0 is a SENTRON molded case circuit breaker (MCCB) rated 250 A at 40 °C, with a 3-pole configuration and a TM240 thermal-magnetic release. Its interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 440 V — figures that govern selectivity and SCCR headroom in a distribution panel. An integrated undervoltage release (UVR) is fitted as the auxiliary release, so the breaker trips on loss of control voltage without an external shunt trip module.
Ratings and what they mean for fit
The 250 A continuous rating holds across 40 °C to 50 °C without derating; above that it steps down to 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. For a panel that runs warm — say a packed enclosure near a drive — the 70 °C figure (223 A) is the real limit, not the catalog 250 A. The TM240 release is a fixed thermal-magnetic unit, not an electronic trip; that means no adjustable long-time or short-time pickup, so coordination studies need to account for the fixed curve. Rated insulation voltage is 800 V, and the breaker is designed for line protection (not motor or generator protection).
Physical fit and panel integration
Dimensions are 105 mm wide, 158 mm high, and 70 mm deep. The 3-pole footprint matches the standard SENTRON 3VA mounting pattern — it bolts directly onto the mounting plate or into a compatible SENTRON distribution panel. No DIN-rail clip on this frame; it is screw-fixed.
Operating conditions and power loss
Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss at rated current is 59.5 W — that heat must be vented in a sealed enclosure, especially when multiple breakers are ganged. The breaker has no communication function, no trip indicator, and no voltage trigger; it is a straight thermal-magnetic device with undervoltage release only.