What this 3VA breaker does on a live line
The SENTRON 3VA2140-8KQ42-0AA0 is a 4-pole molded case circuit breaker rated for 40 A continuous current, designed for line protection — meaning it sits at the feeder or sub-feed to protect cables and busbars, not a specific motor or load group. Breaking capacity hits 440 kA at 240 V AC, 330 kA at 415 V, and still 52.5 kA at 690 V — that's enough to handle high-fault utility feeds or transformer secondaries without needing a current-limiting fuse upstream. It carries a communication function and ground-fault monitoring via summation current of L+N conductors, so it can talk to a PLC or BMS for remote trip indication and leakage detection — no separate ground-fault relay needed on the same feeder.
Panel fit and mounting
Footprint: 140 mm wide by 181 mm tall by 86 mm deep. That 86 mm depth (3.39 in) matters when you're squeezing it into a shallow back-panel enclosure — measure gland-plate clearance before you drill. Rated for storage from -40 °C to 80 °C, operating from -25 °C to 70 °C. No derating across the full 40 A from 40 °C up to 70 °C — that's unusual for a compact MCCB; it means the thermal-magnetic trip holds its full rating even in a hot panel. Power loss is 1.2 W max — negligible for thermal budgeting, but if you're packing a dozen of these in a row, it adds up. No undervoltage release fitted, so it won't drop out on a brownout; that's by design for line-protection duty where nuisance tripping is worse than riding through a sag.
Lifecycle and sourcing posture
Rated insulation voltage is 800 V, so it's suited for 480/277 V and 600 V panels with headroom. The 4-pole construction covers three-phase plus neutral switching — common for North American service-entrance or European TN-S systems.