What this MCCB is and what the ratings mean for fit
The Siemens SENTRON 3VA1132-4EF32-0JH0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current Iu of 32 A, with a TM240 thermal-magnetic overcurrent release. The TM240 designation means the thermal element is fixed at 32 A and the magnetic short-circuit pickup is adjustable — per the release design, the magnetic trip threshold is set at 240 A (7.5× Iu), which is the standard fixed-magnetic value for this release family. The 32 A rating holds flat from 40 °C to 50 °C ambient; above that it derates to 30.72 A at 55 °C, 30.08 A at 60 °C, 29.44 A at 65 °C, and 28.8 A at 70 °C. For a panel designer, that means the breaker can be loaded to its full nameplate in a 50 °C enclosure without derating — a common condition in a packed switchboard — but above that temperature you need to account for the thermal curve. The breaking capacity is the headline figure for fault coordination: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. At 415 V — the common three-phase distribution voltage in much of the world — 75.6 kA SCCR means this breaker can safely interrupt a fault up to that level without upstream cascading. For a site electrical engineer checking selectivity, that 75.6 kA at 415 V gives substantial headroom against a typical 50 kA or 65 kA available fault current on a large industrial service. This is a line-protection version (not motor-protection), so it is intended for feeder and distribution circuits — cable protection, busway taps, panelboard mains. It carries a shunt trip (STL) for remote tripping and comes with 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). The auxiliary contacts let the panel builder wire status feedback to a PLC or annunciator without adding external relays. The integrated auxiliary trip order code is 3VA9688-0BL32, which is the factory-fitted accessory for this build.
Integration and mounting
The breaker occupies a 76.2 mm width (roughly 3 inches — three 1-inch pole spaces on a DIN rail or panel-mount footprint), 130 mm height, and 70 mm depth. The IP40 rating on the front means it is protected against solid objects over 1 mm (tools, wires) but not sealed against moisture; it is intended for indoor panel installation where the enclosure provides the environmental seal. The operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C — the storage limit governs handling and shipping, not running conditions.