400 A continuous, flat derating to 70°C
The Siemens 3VA2440-5MN32-0DC0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for motor protection. It carries a full 400 A continuously from 40 °C up through 70 °C ambient — no derating curve to calculate for typical panel environments. That flat thermal response simplifies coordination: the breaker's continuous rating is the same at the top of its operating range as at the bottom, per the datasheet.
Breaking capacity across voltage classes
Interrupting capacity is specified per voltage: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 9 kA at 690 V. The 240 V figure is among the highest in the 3VA2 frame class — useful for high-fault utility service entrances or transformer secondaries where available fault current exceeds 100 kA. At 690 V the 9 kA rating is the limiting case; verify SCCR against the installation's available fault current at that voltage level.
Motor protection design with integrated undervoltage release
This MCCB is designated for motor protection, meaning its trip curve and thermal memory are tuned for motor starting inrush and locked-rotor conditions. Phase failure detection is built in — the breaker will trip on loss of one phase, which is critical for preventing single-phasing damage on three-phase motor loads. The factory-fitted undervoltage release (UVR) drops the breaker when control voltage falls below the dropout threshold, standard for safety circuits that need to guarantee a power disconnect on loss of control power. Two auxiliary switches (HQ type) are included for status feedback to a PLC or annunciator panel.
Panel fit and dimensions
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. That depth is the front-to-back panel footprint including the handle and terminal covers. Mounts on a standard DIN rail or directly to a backplate via the four mounting slots on the base. The 138 mm width is the 3-pole frame width; adjacent breakers in a multi-unit lineup will need the side-to-side clearance per Siemens' installation instructions.