What this MCCB carries and where it fits
The Siemens SENTRON 3VM1040-3ED46-0AA2 is a 4-pole molded case circuit breaker rated 40 A continuous at 40 °C, with a TM210 thermal-magnetic overcurrent release (LI protective function). It's in the N switching capacity class, meaning it's sized for standard industrial distribution — not the high-breaking version, but still capable of 76 kA at 240 VAC and 53 kA at 415 VAC. That interrupting capacity covers most panelboard and motor control center fault duties up to those voltages without needing a current-limiting fuse upstream. Frame size is 100 A, so the breaker itself is physically larger than the 40 A trip unit suggests — the same frame can be re-rated up to 100 A if you swap the release later.
Ratings that decide the fit
The interrupting ratings drop fast as voltage climbs: 76 kA at 240 V, 53 kA at 415 V, 32 kA at 440 V, and 7.5 kA at 500 V. If your system runs 480 V wye, the 440 V figure is the closest published value — 32 kA — and that's the one to check against your available fault current. The thermal curve holds 40 A from 40 °C up to 50 °C, then derates to 39 A at 55–60 °C and 38 A at 65 °C, 37 A at 70 °C. That's a shallow derate; you don't lose much headroom in a warm enclosure. Rated insulation voltage is 690 V, max operational voltage 500 VAC 50/60 Hz. Box terminals on the front for main circuit connection — standard panel wiring, no special lug kit needed.
Panel integration notes
Front-connected box terminals accept copper or aluminum conductors — strip length and torque per the terminal marking on the breaker. The 4-pole unit occupies the same footprint as the 3-pole frame in the 3VM range; allow clearance for arc chute exhaust above and below. IP40 on the front face means it's protected against solid objects over 1 mm but not sealed against dust ingress — fine for a clean indoor panel, not for washdown areas. Storage range is -40 °C to 80 °C, operating -25 °C to 70 °C. Maximum power loss is 14 W at rated current — negligible for panel heat calc, but worth noting if you're packing a dozen of these in a small enclosure.