What this MCCB delivers for your panel
The Siemens SENTRON 3VA1040-3ED32-0JA0 is a 3-pole molded case circuit breaker rated 40 A continuously at 40 °C — that's the current it carries without derating in a standard 40 °C panel environment. The TM210 thermal-magnetic release handles overload and short-circuit protection in one package, so you don't need a separate relay for motor branch circuits or feeder protection. Breaking capacity hits 75.6 kA at 240 V AC, dropping to 52.5 kA at 415 V and 7.5 kA at 690 V. That 75.6 kA figure at 240 V means this breaker clears high-fault currents on 240 V distribution without upstream fuses — useful for service-entrance or sub-feed applications where available fault current is high. The built-in shunt trip (STL) allows remote tripping via a control signal — a standard requirement for emergency-stop circuits or remote disconnect in automated lines. No undervoltage release is fitted, so the breaker stays closed on control-power loss unless the shunt trip is explicitly triggered.
Mounting and integration
Dimensions are 70 mm deep, 76.2 mm wide, and 130 mm tall — a compact 3-pole footprint that fits standard SENTRON panelboard and distribution board cutouts. The 76.2 mm (3-inch) width is the typical 3-pole MCCB spacing; verify busbar or lug spacing before committing the BOM line. Line protection design means the breaker is configured for feeder and branch-circuit protection, not motor protection with adjustable overload curves. If your application needs adjustable thermal settings, the 3VA1 series offers electronic releases; this fixed TM210 is a straight thermal-magnetic for standard distribution.
Temperature derating — what the numbers mean
Rated current holds at 40 A from 40 °C up to 50 °C ambient. Above that, derating kicks in: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. If your panel runs hot (say 55 °C inside the enclosure), you lose 1.6 A of headroom — still fine for a 40 A feeder, but worth checking if the load is near the limit. Operating temperature range is -25 °C to +70 °C, storage from -40 °C to +80 °C. The storage limit governs handling and warehousing, not running conditions. Power loss at full load is 10.8 W maximum — negligible for panel cooling but adds up in a densely packed enclosure.