SENTRON 3VA line protection breaker with undervoltage release
The Siemens SENTRON 3VA1020-3ED36-0CH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, carrying a continuous 20 A at 40 °C and holding that rating through 55 °C before a single-amp derate at 60 °C. Breaking capacity hits 75.6 kA at 240 V AC, stepping down to 52.5 kA at 415 V and 32 kA at 440 V — enough headroom for most industrial service-entrance or feeder panels where the available fault current is known. The 70 mm depth and 76.2 mm width fit standard 3-pole MCCB panel cutouts, so it drops into existing SENTRON or older 3WL/3VL footprints without re-drilling the mounting plate.
What the ratings mean for your panel
The 20 A thermal-magnetic rating is the continuous current the breaker carries without tripping in a 40 °C ambient — typical for a 40 °C panel interior. If your enclosure runs hotter (say 60 °C), you lose 1 A; at 70 °C you're still at 19 A, so the derate curve is shallow. The 75.6 kA interrupting rating at 240 V tells you this breaker can safely clear a fault up to that current without welding contacts or venting arc gas into the panel — critical for SCCR compliance when the transformer or utility feed can deliver that much fault current. The 800 V rated insulation voltage means the internal clearances and creepage are sized for 690 V systems, so it's comfortable on 480 V or 600 V class supplies.
Integrated auxiliaries and undervoltage release
This variant ships with two auxiliary switches plus a trip alarm switch (HQ) factory-installed, and an undervoltage release (UVR) built in. The UVR means the breaker trips if control voltage drops below a threshold — standard for emergency-stop circuits or undervoltage protection on motor feeders where you don't want automatic reclosure after a dip. The aux switches give you remote status: one set for the main contact position, one for the trip alarm. No communication module on this order code, so it's a standalone breaker — status goes back to the PLC via hardwired inputs, not fieldbus.