The Siemens SENTRON 3VA2040-7HN32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. The 480 A frame means the internal components are sized for a 480 A maximum bus, so the breaker runs cool at 40 A and leaves headroom for future upsizing by swapping the trip unit.
Breaking capacity — the number that decides fault clearance
Rated breaking capacity hits 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3 kA at 690 V.
Maximum power loss is 1.2 W — negligible for thermal budgeting inside a crowded cabinet.
Trip unit and protection features
The ETU350 electronic overcurrent release is a microprocessor-based trip unit with adjustable long-time pickup, short-time pickup, instantaneous pickup, and ground-fault protection (though this specific variant ships without ground-fault monitoring).