What the ratings mean for fit
The 3VA2340-6HN42-0KA0 is a Siemens IEC frame 400 molded-case circuit breaker with a 400 A frame and an interrupting capacity of 85 kA at 415 V AC (class H). That 85 kA rating means it can safely clear a fault up to that level without upstream devices needing to coordinate — critical for high-fault locations like main switchboards or transformer secondaries. The ETU350 electronic trip unit provides LSI protection: long-time (Ir adjustable 160–400 A), short-time (Isd 1.5–10 x Ir), and instantaneous (Ii fixed at 10 x In). The neutral conductor protection is field-adjustable to OFF, 50%, or 100% of the phase setting, which matters when you're feeding a 4-wire system with harmonic loads. The shunt trip accessory (left-mounted, 208–277 V AC 50/60 Hz or 220–250 V DC) allows remote tripping — useful for emergency-stop circuits or interlocking with a fire-alarm panel. The nut keeper kit is included, saving a panel-builder a trip to the hardware bin during assembly.
Deployment context
This breaker mounts in a standard panel or enclosure on a DIN rail or bolted to a backplate. The 4-pole configuration suits three-phase plus neutral applications — common in commercial buildings, industrial switchboards, and machine-tool power distribution. The adjustable N protection is a practical feature for retrofits where the neutral conductor sizing may differ from the phase conductors.