The Siemens SENTRON 3VA1120-6EF36-0DA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection duty, carrying a continuous current Iu of 20 A and a rated insulation voltage Ui of 800 V. Its interrupting capacity reaches 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 690 V — figures that place it in the high-breaking-capacity tier for industrial distribution panels where fault currents can exceed 100 kA. The TM240 overcurrent release provides thermal-magnetic protection; the integrated undervoltage release (UVR) trips the breaker when control voltage drops, a standard requirement for safety circuits in machine tools and conveyor lines. No auxiliary contacts or communication module are fitted on this variant, so any status feedback to a PLC must come from an external auxiliary switch block or the separate 3VA9608-0BB25 auxiliary trip unit.
Thermal derating and panel fit
The breaker holds its full 20 A rating up to 50 °C ambient; above that it derates linearly to 18 A at 70 °C. In a sealed, uncooled enclosure the effective current may be lower — factor the derating curve into the panel thermal budget. Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep, which fits the standard SENTRON 3VA mounting footprint. Front IP40 protection means the breaker is suited for dry indoor panels; no washdown rating. The undervoltage release coil draws its supply from the control circuit — verify the coil voltage matches the panel's control transformer output before wiring.