SENTRON 3VA2 MCCB with ETU850 — 400 A, 3-Pole, Line Protection
The Siemens 3VA2340-5KP32-0BL0 is a SENTRON 3VA2 molded case circuit breaker (MCCB) rated for 400 A continuous current at 40 °C, configured as a 3-pole line-protection device with an ETU850 electronic trip unit. It carries a breaking capacity of 187 kA at 240 V, derating to 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V — figures that govern its fault-interruption capability at the point of common coupling. The ETU850 release provides electronic overcurrent protection with adjustable trip settings, plus a communication function and other measurement functions for integration into a monitored distribution system. An undervoltage release (UVR) is fitted as standard, and the auxiliary contact configuration includes two auxiliary switches, one trip alarm switch, and one electrical alarm switch (HQ type).
Thermal Derating and Panel Fit
The 400 A rating holds at ambient temperatures up to 50 °C; above that it derates linearly to 375 A at 55 °C, 350 A at 60 °C, 325 A at 65 °C, and 300 A at 70 °C. For a panel with a 55 °C internal ambient, the effective continuous current is 375 A — a 6.25 % reduction that must be factored into the busbar and downstream conductor sizing. Dimensions are 138 mm wide, 248 mm high, and 110 mm deep — a standard 3-pole MCCB footprint that fits SENTRON 3VA2 mounting bases and busbar systems. The 98.5 W maximum power loss at rated current must be dissipated within the enclosure; adjacent devices should be spaced per the manufacturer's thermal coordination guidelines.