The Siemens SENTRON 3VA1150-6EF36-0AA0 is a 3-pole molded case circuit breaker rated for 50 A at 40 °C, built for line protection duty. It carries a TM240 thermal-magnetic overcurrent release — the thermal element handles sustained overloads, the magnetic element clears short-circuit faults fast. The 220 kA breaking capacity at 240 V is the headline number, but the real-world fit depends on the voltage on your bus: at 415 V it's 154 kA, at 440 V it's 121 kA, and at 500 V or 690 V it's 17 kA. That means on a 480 V panel this breaker still holds a solid 121 kA SCCR — plenty for most industrial distribution boards.
Ratings and what they mean for fit
Rated current holds at 50 A from 40 °C up to 50 °C, then derates gradually: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, 45 A at 70 °C. If your panel runs hot — say a packed enclosure with drives — the 45 A at 70 °C figure is the one to size against, not the 50 A nameplate. Insulation voltage is rated 800 V, so the breaker is comfortable on 480 V and 600 V class systems. Maximum power loss is 14.6 W, which matters for thermal budgeting in a sealed enclosure. Operating temperature range is -25 °C to 70 °C; storage range goes from -40 °C to 80 °C. Front protection is IP40 — that means protected against tools and wires over 1 mm, but not sealed against dust ingress. Fine for a clean indoor panel; not for washdown or outdoor exposure. The breaker has no undervoltage release, no ground-fault monitoring, no communication function, and no trip indicator. It's a straight line-protection MCCB: install it, feed a bus, and rely on the TM240 release to do its job without extras.
Physical fit and panel integration
Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. That 70 mm depth is the body depth behind the panel face — important when you're routing conductors in a shallow enclosure. The 76.2 mm width is a 3-inch footprint, standard for a 3-pole MCCB this size. Mounts on a DIN rail or bolts directly to a backplate; the SENTRON family shares a consistent cutout pattern, so swapping within the series doesn't mean re-drilling the panel.