Line protection MCCB with integrated undervoltage release
The SENTRON 3VA1120-4EF36-0DH0 is a 3-pole molded case circuit breaker rated 20 A at 40 °C, designed for line protection in distribution panels. Its 121 kA breaking capacity at 240 V handles high-fault scenarios without cascading upstream — critical for maintaining selective coordination in a plant's main or sub-distribution board. The integrated undervoltage release (UVR) trips the breaker if supply voltage drops below a set threshold, protecting motors or sensitive loads from brownout conditions.
Breaking capacity across voltage levels
Breaking capacity is rated per IEC 60947-2: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. This derating curve is typical for MCCBs — the interrupting ability drops as voltage rises. For 480 V systems (common in North America), the 440 V rating of 52.5 kA is the closest published figure; verify coordination with the upstream device.
Thermal derating and panel integration
Rated 20 A continuously from 40 °C through 55 °C; derates to 19 A at 60–70 °C. For a 76.2 mm wide (3 in), 70 mm deep (2.76 in) footprint, factor in the 14.5 W maximum power loss when calculating enclosure heat rise. The 130 mm height (5.12 in) fits standard MCCB cubicle spacing. Undervoltage release and the 2 auxiliary switches + 1 trip alarm switch occupy the accessory slots — confirm wiring access before panel layout.