What it is and what it does
The Siemens 3VA1020-2ED36-0DH0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection in industrial distribution panels. It carries a continuous current Iu of 20 A at 40 °C, with three poles and a TM210 thermal-magnetic overcurrent release that handles both overload and short-circuit faults without needing an external relay. The built-in undervoltage release (UVR) means this breaker will trip if supply voltage drops below a set threshold — useful for preventing motor re-acceleration after a sag or outage. It also ships with 2 auxiliary switches plus a separate trip alarm switch (HQ), so you can wire status feedback back to a PLC or annunciator without adding an external aux block.
Breaking capacity — what the numbers mean
This MCCB's interrupting rating changes with system voltage, which is common for molded case breakers. At 240 V it can clear 52.5 kA of fault current; at 415 V that drops to 32 kA; at 440 V it's 13.6 kA; and at 690 V it's 7.5 kA. The key takeaway for a panel builder or site electrical engineer: verify your available fault current at the installation point against the rating for your actual line-to-line voltage. If you're on a 480 V system, use the 440 V column as a conservative bound.
Thermal derating and operating range
The breaker holds its full 20 A rating from 40 °C up through 50 °C, which covers most panel interiors without a derate. Above that, it steps down: 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C. The operating ambient range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. For a lube-route tech or MRO planner: if this breaker sits near a hot motor starter or a sun-baked enclosure, check the actual panel temperature against that derating curve — a 20 A breaker pulling 18 A continuous at 70 °C is still fine, but don't load it to nameplate at those temps.
Physical fit
Dimensions are 130 mm high, 76.2 mm wide, and 70 mm deep. It's a standard SENTRON 3VA frame size, so it clips onto the same DIN rail footprint as other 3VA three-pole breakers. The IP40 front protection means it's fine for a dry indoor panel but not for washdown areas — keep it behind a sealed enclosure door if there's moisture or dust around.