MCCB for line protection — 40 A, 4-pole, TM240 trip
The Siemens SENTRON 3VA1140-3EF42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated 40 A, designed for line protection in distribution panels. It carries a TM240 thermal-magnetic trip unit and is rated for an insulation voltage of 800 V. The interrupting capacity reaches 75.6 kA at 240 V.
Thermal derating and panel fit
The breaker is rated 40 A continuously at ambient temperatures from 40 °C through 50 °C. At 55 °C it derates to 39 A, at 65 °C to 38 A, and at 70 °C to 37 A. If your panel ambient runs hot — say, a packed enclosure with drives — factor that derating into your load schedule; the 40 A frame is good for a 37 A continuous load at 70 °C. Dimensions are 130 mm height, 101.6 mm width, and 70 mm depth, which fits standard SENTRON 3VA panel cutouts. Front-side IP40 protection means it's protected against tools and wires >1 mm but not against water ingress — suitable for indoor switchgear, not washdown zones. Maximum power loss is 10.8 W, worth noting for thermal calculations in sealed enclosures.