The 75.6 kA interrupting rating at 240 V AC gives substantial fault-current headroom for most industrial service-entrance or feeder applications — at 415 V it still clears 52.5 kA, and at 690 V it holds 11.9 kA, so the same breaker covers mixed-voltage panels without a derating surprise.
Ratings and thermal performance
At 55 °C it drops one amp to 39 A, and by 70 °C it's at 37 A. That thermal curve means a panel builder can load this breaker to its full 40 A in a standard 40 °C environment without over-specifying. Power loss at rated load is 10.8 W — modest for a 4-pole frame, but worth accounting for in a densely packed enclosure.
The 3VA1140-3GF42-0AA0 occupies a 101.6 mm wide, 130 mm tall, 70 mm deep footprint — a standard 4-pole MCCB frame that fits most DIN-rail or panel-mount enclosures without surprise. Front face is IP40 rated, so it's protected against tools and solid objects larger than 1 mm; the rest of the breaker body is open to the enclosure for heat dissipation.