What this MCCB carries — and what it doesn't
The Siemens 3VA1080-3ED42-0CH0 is a 4-pole SENTRON molded case circuit breaker rated for 80 A continuous at 40 °C, with a TM210 thermal-magnetic release and an undervoltage release (UVR) built in. The interrupting ratings climb to 75.6 kA at 240 V and 52.5 kA at 415 V — numbers that tell you it's sized for high-fault industrial panels, not light commercial. The 4-pole construction means it switches the neutral, which matters for TN-S or IT systems where you need full isolation on all conductors.
Thermal derating — the real current you get
The 80 A rating holds flat from 40 °C to 50 °C, then starts to taper: 76.8 A at 55 °C, 75.2 A at 60 °C, 73.6 A at 65 °C, and 72 A at 70 °C. If your panel ambient runs hot — say, next to a drive cabinet or in a non-climate-controlled enclosure — the effective continuous current drops. Plan the load at 72 A if the enclosure hits 70 °C; the breaker won't nuisance-trip, but it also won't carry a full 80 A.
Interrupting capacity across voltages
This breaker delivers 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at 690 V. The steep drop at 690 V is typical for a compact MCCB frame — the arc extinction physics limit the interrupting capability as voltage rises. For a 690 V feeder, you need to confirm the available fault current is under 7.5 kA, or step up to a larger frame. At 415 V, 52.5 kA covers most industrial distribution panels with transformer ratings up to 2 MVA.
Auxiliary contacts and trip alarm — what's wired in
The 3VA1080-3ED42-0CH0 ships with 2 auxiliary switches plus 1 trip alarm switch (HQ type). The auxiliary contacts follow the main contact position; the trip alarm signals only on a fault trip (overcurrent or undervoltage), not on manual open. That's the contact you'd wire to a PLC input for a shunt-trip or alarm annunciator. The integrated undervoltage release (UVR) is factory-fitted — if the control voltage drops below the dropout threshold, the breaker opens instantly. No separate UVR module to mount and wire.