What it is and what it does
The Siemens SENTRON 3VA1120-6EF32-0DH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels and industrial switchgear. It carries a rated current of 20 A across the ambient range from 40 °C through 55 °C, derating to 19 A at 60 °C and above — so the 20 A rating holds in most ventilated enclosures without a derate penalty. The interrupting capacity reaches 220 kA at 240 V, 154 kA at 415 V, and 121 kA at 440 V, which places it in the high-breaking category for fault currents at the service entrance or in large motor-control-center feeders. A rated insulation voltage of 800 V gives headroom for 690 V systems, and the breaker ships with an integrated undervoltage release (UVR) plus two auxiliary switches and one trip-alarm switch — enough feedback for remote status monitoring without adding accessory modules.
Panel fit and integration
The breaker measures 76.2 mm wide, 130 mm tall, and 70 mm deep — a 3-pole footprint that fits standard SENTRON 3VA panel cutouts and busbar systems. Maximum power loss is 14.5 W, which matters for thermal budgeting in a sealed enclosure; adjacent units need the manufacturer's spacing rules to avoid cumulative heating. The design includes a trip indicator and supports line-protection-only duty (no ground-fault monitoring version).