What the ratings mean for fit
The Siemens 3VA1140-6GE42-0AA0 is a SENTRON molded case circuit breaker (MCCB) with a 40 A continuous rating across its full ambient range — it holds 40 A from 40 °C up to 50 °C, then derates to 39 A at 55 °C and 60 °C, and 38 A at 65 °C, down to 37 A at 70 °C. That means in a warm panel you lose only a few amps; no need to oversize for a typical 40 °C enclosure. The 4-pole design handles three-phase plus neutral, common for North American and European distribution panels. The TM220 overcurrent release combines a thermal-magnetic trip — thermal for overload, magnetic for short-circuit — with a fixed 40 A rating, so it's a line-protection breaker, not a motor-protection device with adjustable thermal settings. Breaking capacity is the headline: 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. That 220 kA at 240 V is high — it safely interrupts faults in high-available-fault-current locations like transformer secondaries or large busway feeds without needing a current-limiting fuse upstream. At 690 V the 17 kA still covers most industrial distribution.
Lifecycle and sourcing reality
The lifecycle stage is marked current, meaning Siemens still actively produces this order code. No end-of-life notice or last-time-buy window is available. Rated insulation voltage is 800 V. Power loss at rated current is 10.8 W. IP40 on the front.
Panel integration notes
Dimensions: 130 mm height, 101.6 mm width, 70 mm depth. The 101.6 mm width is a standard 4-inch footprint.