What it is and what it does
The Siemens SENTRON 3VM1140-4EE42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 40 A continuous current, built for line protection duty in distribution panels and motor control centers. It carries a TM220 thermal-magnetic release — the thermal element handles overloads, the magnetic element clears short circuits — and is rated for a maximum of 40 A adjustable response current (Ir). The interrupting ratings tell the real story: 121 kA at 240 VAC, 76 kA at 415 VAC, 53 kA at 440 VAC, and 11.9 kA at 500 VAC. That 121 kA at 240 V means it can safely clear a fault where the available short-circuit current is as high as 121,000 amps — typical for large transformer secondaries or high-capacity busway feeds. At 415 V the 76 kA rating still covers most industrial service-entrance conditions. Thermal derating is minimal through 50 °C — it holds 40 A flat. Above that it drops gradually: 39 A at 55 °C and 60 °C, 38 A at 65 °C, 37 A at 70 °C. If your panel ambient runs hot, that 37 A at 70 °C is the number to size against, not the 40 A nameplate. The insulation voltage rating is 690 V, and it can handle up to 500 V DC on the DC side.
Panel fit and integration
The 3VM1140-4EE42-0AA0 measures 70 mm deep, 101.6 mm wide, and 130 mm tall. That 101.6 mm width — exactly 4 inches — fits standard MCCB mounting footprints in distribution panels. Depth of 70 mm means it clears most shallow enclosures without needing a gland-plate extension. Front protection is IP40, so it's fine for indoor panels but not washdown environments. Maximum power loss is 10.8 W per pole — total about 43 W for the four-pole unit. That's modest, but in a densely packed panel with multiple breakers, the cumulative heat needs to be vented. No communication module, no motor drive option, no ground-fault monitoring on this version — it's a straight thermal-magnetic breaker with no add-on accessories. Latching endurance is rated at 12,000 operations — that's the mechanical life before the latching mechanism wears. For a main breaker that sees a few operations a year, that's effectively lifetime. For a frequently switched disconnect, it's a limit to track.