The Siemens SENTRON 3VA2340-5HL32-0AG0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current (Iu) at 40 °C, with an ETU320 electronic trip unit for line protection. This is the breaker you specify when the main feeder or a large downstream load needs adjustable thermal-magnetic or electronic protection in a 400 A frame — common for industrial distribution panels, machine tool infeed, or building main switchboards. Breaking capacity is voltage-dependent: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. At 690 V the 17 kA figure is lower but still adequate for most motor-control-center applications where the upstream transformer impedance limits fault current. The ETU320 trip unit provides electronic overcurrent protection with adjustable settings (not detailed in this listing but standard for the ETU320 platform — typically long-time pickup, short-time pickup and delay, instantaneous, and ground fault).
Panel footprint and thermal derating
Depth of 110 mm means it fits within a 200 mm-deep enclosure with room for rear cable connections and the integrated auxiliary trip (supplied as 3VA9608-0BB11). Thermal derating is published: full 400 A from 40 °C through 50 °C, then 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. Maximum power loss is 96 W, which contributes to the enclosure's thermal budget.
The basic switch supplied inside this breaker is order code 3VA2340-5HL32-0AA0, and the integrated auxiliary trip is 3VA9608-0BB11. If you are repairing an existing unit, those subcomponents are orderable separately. The auxiliary contact configuration (1 auxiliary switch + 1 trip alarm switch HP) is fixed at the factory — not field-convertible without replacing the auxiliary contact block.