The Siemens SENTRON 3VA2140-7KQ32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. The ETU860 electronic trip unit gives you adjustable time-current curves (tr min 0.5 s to tr max 25 s, tsd max 0.5 s) so you can coordinate selectively downstream.
Sizing and selectivity notes
That simplifies panel design in warm enclosures or near other heat sources. The ETU860 release lets you set the short-time delay (tsd) up to 0.5 s, which gives downstream breakers time to clear a fault before this one opens, preserving uptime on unaffected feeders. The interrupting capacity drops to 3.8 kA at 690 V.