What this MCCB carries
The Siemens SENTRON 3VA1225-6EF42-0AC0 is a 4-pole molded case circuit breaker (MCCB) rated 250 A at 40 °C, fitted with a TM240 thermal-magnetic overcurrent release. It is designed for line protection in distribution panels and switchgear assemblies. Breaking capacity runs 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V — that covers most industrial service-entrance and feeder applications where high fault current is expected. Insulation voltage is rated 800 V, and the unit dissipates 57 W at full load. Operating temperature range is -25 °C to +70 °C, with storage from -40 °C to +80 °C.
Current derating and thermal profile
Rated current holds at 250 A from 40 °C through 50 °C, then steps down: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. For a panel running warm — say 55 °C ambient inside the enclosure — the breaker still delivers 243 A continuous without nuisance tripping.
Auxiliary switching and accessories
The breaker ships with two HQ auxiliary switches fitted (design of the auxiliary switch: 2 auxiliary switches HQ). No undervoltage release, no ground-fault monitoring, no communication function — it is a straight thermal-magnetic line protection breaker. The supplied basic switch order code is 3VA12256EF420AA0.
Panel fit and dimensions
Footprint: 140 mm wide, 158 mm tall, 70 mm deep. That 140 mm width for a 4-pole frame is standard for SENTRON 3VA molded case breakers — it occupies the same mounting pattern as other 4-pole units in the series, so a panel laid out for a 3VA1110 4-pole will accept this 250 A frame without drilling new holes.