Siemens 3VA1140-4EF42-0AA0 — 40 A 4-Pole MCCB, TM240 Release, Active Production
Breaking capacity is the headline number here: 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and it still holds 11.9 kA out to 690 V. That means this breaker clears high-fault currents without welding its contacts or venting arc gas into the panel — important when you're protecting a transformer secondary or a bus feeding multiple motor starters. The 4-pole version lets you switch the neutral, which is required on some IT or corner-grounded delta systems.
Thermal derating and panel fit
The 40 A rating holds flat from 40 °C to 50 °C ambient, then drops to 39 A at 55–60 °C and 38 A at 65 °C, hitting 37 A at 70 °C. If your panel runs hot — say next to a drive cabinet or a furnace line — you'll need to either upsize the breaker or keep the load below 37 A. The maximum power loss is 10.8 W, so heat dissipation inside the enclosure is manageable even with several breakers ganged. Dimensions are 70 mm deep by 101.6 mm wide by 130 mm tall. That's a standard SENTRON 4-pole footprint — it clips onto the DIN rail and leaves room for auxiliary contacts or a motor drive on the side. Front IP40 means it's protected against tools and wires larger than 1 mm, but you wouldn't hose this down; keep it inside a sealed enclosure if there's washdown nearby.
Sourcing and lifecycle — active, quoted to order
Current-production Siemens SENTRON part. Sourced through independent distribution and quoted against an RFQ; availability and pricing confirmed at quote time. Rated insulation voltage is 800 V, and the maximum DC operational voltage is 600 V — so it works in DC distribution panels as well as AC, though the breaking capacity figures above are AC. The TM240 release is a fixed thermal-magnetic unit; if you later need adjustable electronic trip or ground-fault, you'd look at a different 3VA variant with a different trip block.