Siemens SENTRON 3VA2040-8HM32-0AA0 — 40 A MCCB, Line Protection, 3-Pole
The Siemens 3VA2040-8HM32-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. Its 3-pole design with a 16–40 A adjustable thermal-magnetic trip suits it for line protection in distribution panels feeding motor control centers or lighting sub-panels. At 415 V it interrupts 330 kA, which covers high-fault-current scenarios common in industrial switchgear close to the transformer secondary.
Breaking capacity and fault clearance
The 330 kA at 415 V and 440 kA at 240 V place this in the highest interrupting class for a 40 A frame — it clears faults without cascading to upstream breakers. At 690 V it still holds 52.5 kA, enough for 480 V delta-connected loads. Insulation voltage is rated 800 V, so the breaker itself is not the voltage bottleneck in a 690 V panel.
Ground-fault monitoring and trip configuration
This variant includes summation-current ground-fault monitoring, meaning it sums the L-conductor currents internally to detect residual imbalance — no external CT or relay module needed. The trip indicator is absent, so fault cause is not stored on the breaker face; pair it with a remote indication contact if post-trip diagnostics matter. Undervoltage release is not fitted, and there is no communication function — this is a standalone thermal-magnetic breaker, not a smart trip unit.
Panel integration and dimensions
Mounts on DIN rail or direct panel with the SENTRON base adapter. The 105 mm width and 181 mm height fit standard Siemens 3VA modular spacing — drops into the same cutout as other 3VA20-frame breakers. Depth is 86 mm, leaving clearance for rear-access busbars in a 200 mm deep enclosure. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C.