The Siemens SENTRON 3VA1120-4EF32-0AD0 is a 3-pole molded case circuit breaker rated for line-protection duty, carrying 20 A continuously at 40 °C ambient and delivering a 75.6 kA interrupting capacity at 415 V — enough to clear a fault on a 400 V distribution board without upstream coordination issues. Maximum power dissipation is 12 W at rated load — factor that into enclosure thermal rise if the cabinet is densely packed.
Interrupting capacity across voltage bands
SCCR drops as line voltage rises: 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. The 690 V figure is the same as 500 V — the breaker is not a high-voltage device, but it can clear a fault on a 690 V line if the available fault current stays under 11.9 kA.
Thermal derating and ambient range
Rated 20 A from 40 °C through 55 °C, then derates to 19 A at 60 °C and 65 °C, and holds 19 A at 70 °C as well.
Panel fit — dimensions and auxiliary switch option
Footprint: 76.2 mm wide, 130 mm tall, 70 mm deep — standard 3-pole MCCB envelope that fits most DIN-rail or panel-mount bases without resizing the gland plate.