What it is and what it does
The Siemens 3VA2040-7HM46-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. Rated continuous current is 40 A at 40 °C, with an adjustable thermal-magnetic trip range from 60 A minimum to 480 A maximum — so it protects feeders and branch circuits where the load current stays under 40 A but the fault-clearing requirement is high. It carries 4 poles, meaning it switches all three phases plus neutral in a 3-phase 4-wire system. The interrupting ratings are substantial: 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3 kA at 690 V — this breaker is sized for high-fault-current installations where upstream transformer capacity is large.
What the ratings mean for fit
The 40 A continuous rating holds flat across ambient temperatures from 40 °C through 70 °C. The 800 V rated insulation voltage (Ui) confirms suitability for 480 V class systems. Physical footprint: 86 mm deep, 140 mm wide, 181 mm high. That width and depth are standard for a 4-pole MCCB in this frame size — it mounts on a DIN rail or directly to a backplate via the integrated lugs. The 1.2 W maximum power loss is negligible for panel thermal budgeting.