What this part is and what it does
The Siemens SENTRON 3VA2340-7HL32-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, designed for line protection in industrial distribution panels. It carries the ETU320 electronic trip unit, which provides adjustable long-time and short-time delay curves plus instantaneous protection — a solid choice for feeder or main breaker duty where selectivity and coordination matter.
Key ratings and what they mean for your panel
The 400 A continuous rating holds flat from 40 °C through 50 °C, then derates to 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your enclosure runs hot, you lose 15 % of capacity at the top of the ambient range — factor that into your load budget. Interrupting capacity is 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 7.5 kA at 690 V. The steep drop at 690 V means this breaker is not your first choice for a 690 V main — verify the available fault current against the 7.5 kA ceiling before specifying. Rated insulation voltage is 800 V, and the front face carries IP40 protection — fine for a clean indoor panel, but not for washdown environments. Maximum power loss is 96 W at rated current. That heat stays inside the enclosure; make sure your thermal calculation accounts for it, especially in a multi-breaker lineup.
What the trip unit gives you
The ETU320 is an electronic trip unit with adjustable settings. It supports long-time pickup and delay, short-time pickup and delay (with I²t on/off), and instantaneous pickup. That adjustability is what lets you coordinate this breaker downstream of a larger main or upstream of branch breakers — you can shape the curve to avoid nuisance tripping on motor inrush while still clearing a hard fault fast.
Physical fit and mounting
Dimensions are 248 mm high, 138 mm wide, and 110 mm deep. It mounts via the standard MCCB footprint — four-bolt pattern, rear or front terminals depending on the accessory kit. No DIN-rail clip; this is a bolted-frame breaker for fixed installation in a distribution board or switchgear cubicle.