What this MCCB is and what it does
The Siemens 3VA1040-4ED32-0HH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in industrial power distribution. It carries a 40 A rated current at 40 °C, with a 3-pole configuration and a breaking capacity of 75.6 kA at 415 V — enough to handle high-fault scenarios in a main or feeder panel without cascading upstream. The insulation voltage is rated 800 V, and the breaker includes a shunt trip release (STL) plus two auxiliary switches and one trip alarm switch (HQ) — so it can signal a remote PLC or annunciator when it trips, and be remotely tripped via the shunt coil. Rated current holds at 40 A up to 50 °C ambient; above that it derates to 38.4 A at 55 °C and 36 A at 70 °C. The maximum power loss is 10.8 W, which matters for thermal management inside a sealed enclosure.
Breaking capacity across voltages
This MCCB delivers 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. The steep drop above 500 V means it's best suited for 400 V-class systems — at 690 V the 11.9 kA rating still covers most industrial secondary distribution, but verify coordination with upstream devices.
Physical fit and mounting
Dimensions are 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole MCCB footprint that mounts on a DIN rail or directly to a backplate. The 70 mm depth leaves clearance for wiring and auxiliary modules in a typical 200 mm deep enclosure.