SENTRON 3VA1120-4ED42-0AA0 — 20 A MCCB for Line Protection
The Siemens SENTRON 3VA1120-4ED42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 20 A continuous current at 40 °C, with a TM210 thermal-magnetic overcurrent release designed for line protection. Its 121 kA breaking capacity at 240 V AC gives substantial fault-current headroom in low-voltage distribution panels, reducing the need for upstream current-limiting fuses.
Breaking Capacity Across Voltages
Rated short-circuit breaking capacity drops with system voltage: 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. At 690 V the 11.9 kA figure is the limiting case — verify the available fault current at the installation point before specifying this breaker for 690 V lineups.
Thermal Derating and Ambient Range
The 20 A rating holds steady from 40 °C through 55 °C, then derates to 19 A at 60 °C through 70 °C. Operating ambient spans -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 12 W maximum power loss at full load matters for panel heat-budget calculations when multiple breakers are ganged.
Physical Fit and Protection
Dimensions are 101.6 mm wide, 130 mm tall, and 70 mm deep — a standard 4-pole MCCB footprint for DIN-rail or panel-mount installation. Front-face protection is IP40, meaning tools and fingers are kept out but the device is not sealed against moisture; install in a dry enclosure or add a gland plate for washdown areas.