What this 3VA2 is and what it does
The Siemens SENTRON 3VA2440-7KP42-0AA0 is a 4-pole molded case circuit breaker rated for line protection, carrying a continuous current Iu of 400 A. It uses the ETU850 electronic trip unit. Breaking capacity is the headline number here: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 9 kA at 690 V. That 330 kA at 240 V is high — this breaker is sized for high-fault utility or transformer-secondaries where available fault current is extreme. The 9 kA at 690 V is a reminder that the same arc-extinction physics doesn't scale linearly; if your system is 690 V, this is not the high-interrupt choice. It also carries communication and other measurement functions onboard, meaning it can report status and metering data back to a controller — useful for a panel that needs load monitoring without a separate power meter. The N-conductor protection is adjustable from OFF to 20% up to 130%, so it handles 4-wire systems with neutral protection as needed.
Physical fit and panel integration
Dimensions: 248 mm high, 184 mm wide, 110 mm deep. That 184 mm width on a 4-pole frame is standard for this class — it occupies four 45 mm pole spaces on a DIN rail or panel-mount footprint. The IP40 rating on the front means it's protected against tools and wires >1 mm, but not against water ingress; keep it inside a sealed enclosure if washdown is nearby. Power loss is 63.3 W maximum at rated current. That's not trivial — if you're packing multiple breakers in a closed panel, factor that heat into your ventilation or derating calculation. The operating temperature range is -40 °C to 70 °C, storage from -40 °C to 80 °C.
Selectivity and coordination notes
Rated insulation voltage Ui is 800 V. The ETU850 trip unit allows fine-tuning of the long-time pickup, short-time pickup, and instantaneous settings.