What it is and what it does
The Siemens 3VA1020-4ED36-0DH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection in distribution panels. It carries 20 A continuously at 40 °C ambient, with no derating needed up to 55 °C — still 20 A — and only a 1 A drop at 70 °C, so it holds its rating across typical enclosure temperatures. Three poles handle three-phase circuits. The interrupting capacity is 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 — high enough for most industrial service-entrance or feeder applications where fault currents are substantial.
Built-in auxiliary and release options
This breaker ships with an undervoltage release (UVR) and a set of auxiliary switches: two auxiliary contacts plus one trip-alarm switch (HQ). That means it can be wired into a safety circuit that drops the breaker on loss of control voltage, and the auxiliary contacts report breaker status back to a PLC or annunciator without needing an external interlock relay.
Panel fit and dimensions
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard MCCB footprint that fits most DIN-rail or panel-mount enclosures. The 70 mm depth leaves room for wiring behind the panel door without crowding.