What this MCCB delivers
The Siemens 3VA2040-8HM36-0AA0 is a SENTRON 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. Three poles, line-protection version, fitted with the ETU330 electronic trip unit. Breaking capacity hits 440 kA at 240 V, 330 kA at 415/440 V, and still holds 53 kA at 690 V, so it handles high-fault utility feeds without cascading upstream.
Trip unit and selectivity
The ETU330 electronic release gives adjustable long-time delay (tr) from 0.5 s to 17 s, letting you coordinate downstream breakers for selective tripping — critical on a distribution panel where you want the branch breaker to clear before the main. Rated insulation voltage Ui is 800 V, so it's comfortable in 480/600 V systems with headroom.
Panel fit and environment
Dimensions: 181 mm tall, 105 mm wide, 86 mm deep — fits standard MCCB mounting footprints. Front face is IP40, suitable for enclosed panel mounting where the door provides the seal. Operating temperature spans -40 °C to 70 °C; storage range is the same on the low end, max 80 °C. Power loss is only 1.2 W maximum, so heat buildup in a dense cabinet is minimal. An optional motor drive can be added for remote tripping or re-closing.