What this breaker brings to the panel
The Siemens 3VA2340-5HL42-0KB0 is a 4-pole IEC frame 400 molded case circuit breaker with a 55 kA interrupting capacity at 415 V AC — class M breaking capacity, meaning it clears high fault currents typical in industrial distribution without cascading upstream. The ETU320 LI trip unit gives you adjustable overload protection (Ir from 160 A to 400 A) and short-circuit pickup (Ii from 1.5 to 10 x In), so you dial in the protection curve to match the feeder or motor load, not the other way around. It ships with a shunt trip rated 208-277 V AC, 50/60 Hz, and two auxiliary switches for status feedback to the PLC or panel indicators. The neutral conductor protection is adjustable — OFF, 50%, or 100% of the phase rating — handy for 4-wire systems where you need to coordinate ground-fault or harmonic currents without nuisance trips.
What the ratings mean for fit
The 55 kA at 415 V AC is the interrupting rating for this IEC frame 400 breaker. If your available fault current is lower, you have headroom; if higher, you need an upstream current-limiting device. The ETU320 is a Li (long-time and instantaneous) electronic trip unit — no short-time delay. For selectivity with downstream breakers, use an ETU350 or ETU550.
Panel integration notes
Mounts on a standard DIN rail or can be screw-fixed to a backplate — the frame 400 footprint is common across the 3VA2 line, so panel cutouts and busbar positions stay consistent if you swap ratings. The shunt trip occupies the left accessory slot; the two auxiliary switches fit the right side. Wire the shunt trip coil to a normally open emergency-stop circuit — it's a trip-to-open function, so loss of control power opens the breaker. The nut keeper kit (included per the order code suffix) prevents the busbar connection nuts from backing off under vibration — a small detail that saves a callout on a motor control center with frequent starts.