Siemens SENTRON 3VA1140-6EF36-0DA0 — 40 A MCCB with Undervoltage Release
The Siemens SENTRON 3VA1140-6EF36-0DA0 is a 3-pole molded case circuit breaker (MCCB) rated for 40 A continuous at 40 °C ambient, with a TM240 thermal-magnetic overcurrent release and an integrated undervoltage release (UVR). It carries a 220 kA interrupting rating at 240 V AC — that is the short-circuit current it can safely clear without welding contacts or rupturing the case, which matters when coordinating downstream feeders in high-fault panels. The UVR (undervoltage release) trips the breaker when supply voltage drops below a set threshold, protecting motors and sensitive loads from brownout damage.
Breaking Capacity and Thermal Performance
Breaking capacity drops with system voltage: 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V and 690 V. That 17 kA floor at higher voltages still covers most industrial distribution panels. The 40 A rating holds steady from 40 °C to 50 °C, then derates gradually to 37 A at 70 °C — so in a hot enclosure near the top of the panel, you lose about 3 A of headroom. Insulation voltage is rated 800 V, meaning the breaker's internal clearances and creepage distances are designed for 690 V systems with margin.