Line protection MCCB with ETU850 — what the ratings mean for fit
The Siemens 3VA2140-8KP32-0AA0 is a SENTRON molded case circuit breaker (MCCB) sized for 40 A continuous duty, carrying the ETU850 electronic trip unit. That 40 A holds flat across the full ambient range from 40 °C to 70 °C — no derating needed in a warm enclosure, which is unusual for a breaker this compact. The 3-pole design with 800 V rated insulation voltage suits it for 400 V class distribution panels feeding motor control centers or branch circuits. Breaking capacity is the standout: 440 kA at 240 V AC, 330 kA at 415 V and 440 V, 220 kA at 500 V, and still 53 kA at 690 V. That means it handles high-fault scenarios upstream near the transformer or in industrial mains without cascading to downstream gear. For a panel builder, this avoids needing a current-limiting upstream breaker — the 3VA2140-8KP32-0AA0 clears the fault itself.
Communication and integration
This MCCB includes a communication function, which means it can report status and trip events to a higher-level control system — useful for a plant-wide power monitoring scheme. The ETU850 release offers adjustable time-current curves (tr min 0.5 s, tr max 25 s; tsd max 0.5 s) so you can coordinate selectivity with downstream breakers without sacrificing speed on hard faults. Dimensions are 105 mm wide, 181 mm tall, 86 mm deep — a standard SENTRON 3VA2 footprint. It mounts on a DIN rail or can be screw-fixed to a backplate; the IP40 front protection means it's suited for enclosed panels where dust ingress is controlled. Power loss is only 1.2 W maximum, negligible for thermal budgeting inside a sealed cabinet.
Panel fit and mechanical endurance
Mechanical endurance is rated at 20 000 operations — typical for an MCCB in a distribution role where it operates as a switch-disconnector occasionally, not daily like a contactor. The storage temperature range (-40 °C to 80 °C) and operating range (-40 °C to 70 °C) cover cold storage and hot plant floor conditions without special derating.