The Siemens SENTRON 3VA1020-4ED32-0HC0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a 20 A continuous current at 40 °C ambient and a 121 kA interrupting capacity at 240 VAC. That interrupting rating means it can safely clear a fault up to 121 kA without welding contacts or cascading failure upstream — critical for high-fault panels near large transformers or utility feeds. The 800 V rated insulation voltage gives headroom for 480 V and 600 V class systems.
Interrupting ratings across voltages
The interrupting capacity drops as voltage rises: 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. For a 480 V panel, the 52.5 kA figure at 440 V is the closest reference — the actual SCCR at 480 V will be between the 440 V and 500 V values, so coordination studies should use the 500 V column as a conservative floor. The 11.9 kA at 690 V is the hard limit for 690 V lineups.
Thermal derating and panel integration
The breaker holds 20 A from 40 °C through 55 °C without derating. At 60 °C it drops to 19 A, and holds at 19 A through 70 °C. That flat derating curve simplifies panel layout — no need to oversize the frame for a warm enclosure. The 70 mm depth and 76.2 mm width fit standard SENTRON 3VA mounting footprints; the 130 mm height leaves clearance for gland plates and busbar covers.
Auxiliary and release options
This variant ships with a shunt trip (STL) release and two HQ auxiliary switches. The shunt trip allows remote tripping from a PLC or emergency-stop circuit — the auxiliary switches provide status feedback (open/closed/tripped) to the control system. No undervoltage release is fitted, so the breaker will not drop out on a brownout unless the shunt trip is wired for that function.