What this MCCB is and what the ratings mean for your panel
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. The ETU350 electronic trip unit provides adjustable overload and short-circuit protection curves, giving you selectivity coordination downstream without nuisance tripping on motor inrush.
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. At 415 V, that 242 kA SCCR means this breaker can safely interrupt a fault up to 242 kA without welding contacts or cascading failure upstream — critical for high-fault panels near large transformers. The 3 kA rating at 690 V reflects the arc-extinction limits at elevated voltage; if your system runs 690 V, verify the available fault current stays under that ceiling.
Panel fit and environmental limits
Dimensions are 105 mm wide, 181 mm high, and 86 mm deep — standard footprint for a 3VA2 frame MCCB, mounts on a DIN rail or directly to a panel backplate via the screw terminals. IP40 on the front means tools and fingers are protected, but the breaker is not sealed against washdown; keep it inside a closed enclosure in wet areas. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. 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). No undervoltage release, no voltage trigger, no communication function, no trip indicator — this is a base-line-protection breaker for distribution feeder or branch circuits where remote signaling isn't required. Insulation voltage rated at 800 V, so it's suitable for 480/277 V and 600 V systems with margin.