What it is and what it does
The Siemens 3VA1080-4ED42-0AF0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — the main disconnect and fault isolator in a distribution panel, motor control center, or switchboard. Four poles handle three-phase plus neutral, or dual-supply configurations. It carries an 80 A continuous rating at 40 °C, with thermal-magnetic trip curve TM210 for overload and short-circuit response. At 240 V it interrupts 121 kA; at 415 V it's still 75.6 kA, so it handles high available fault current without cascading upstream.
Ratings that decide the fit
The 80 A rating holds across 40–50 °C ambient; derate to 78 A at 55 °C, 77 A at 60 °C, 75 A at 65 °C, and 74 A at 70 °C. That thermal curve matters when the breaker lives in a crowded, warm enclosure — you don't lose headroom until above 50 °C. Insulation voltage is rated 800 V, so it's comfortable on 480/277 V and 600 V systems. Breaking capacity steps down with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. That 11.9 kA at 690 V tells you this frame is optimized for low-voltage distribution (under 480 V), not 690 V industrial mains. The TM210 release is thermal-magnetic with a fixed thermal pickup and magnetic trip at 10x In — standard for general distribution.
Mounting and integration
Dimensions: 130 mm tall, 101.6 mm wide, 70 mm deep — a compact 4-pole frame that fits standard panel layouts. The auxiliary switch configuration is 1 auxiliary + 1 trip alarm switch HQ, giving you a status signal for PLC or annunciator without an add-on module. No undervoltage release, no communication module, no ground-fault monitoring on this variant — it's a straight line-protection breaker. Power loss at full load is 19.2 W max, so factor that into enclosure thermal calculations if you're packing multiple breakers.