Line protection with ETU850 — what the ratings mean for panel fit
The 3VA2040-8KP46-0AA0 is a Siemens SENTRON molded case circuit breaker (MCCB) rated for 40 A continuous at 40 °C, with no derating needed up to 70 °C — the full 40 A holds across the operating range. That makes it a straight drop-in for a 40 A feeder or branch circuit without recalculating ambient temperature margins. The interrupting ratings are the headline: 440 kA at 240 V, 330 kA at 415 V and 440 V, 220 kA at 500 V, and 52.5 kA at 690 V. For a 480 V panel (common in North American industrial), the 220 kA at 500 V figure applies — that is well above typical available fault current in most distribution switchboards, so it gives headroom for high-fault locations like substation mains or large motor control centers. It uses the ETU850 electronic trip unit, which means adjustable long-time, short-time, instantaneous, and ground-fault protection curves — not a fixed thermal-magnetic. That lets the specifying engineer coordinate selectively with downstream breakers, which is the main reason to pick this over a cheaper thermal-magnetic MCCB. Four poles, so it switches all three phases plus neutral. The front face carries IP40 protection — fine for a dry indoor panel, but not for washdown areas.
Panel integration — dimensions and mounting
Dimensions are 86 mm depth, 140 mm width, 181 mm height. That 140 mm width is the standard 4-pole MCCB footprint for the SENTRON 3VA2 frame — it fits the same panel cutout and busbar spacing as other 3VA2 four-pole units. Rated insulation voltage is 800 V, with a maximum operating temperature of 70 °C and storage range from -40 °C to 80 °C. Power loss is 1.2 W maximum — negligible for panel thermal calculations.