What it is and what it does
The Siemens 3VA1020-4ED32-0KA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) configured for line protection, with a TM210 thermal-magnetic overcurrent release and a rated continuous current (Iu) of 20 A. Rated insulation voltage (Ui) is 800 V, and the interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V — covering most low-voltage distribution panels without a cascading coordination study.
Thermal performance and derating
The 20 A rating holds steady from 40 °C up to 50 °C. At 55 °C it derates to 19.2 A, then 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C — so in a warm panel you lose about 10 % of the continuous rating at the top of the operating range. Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing, not running conditions.
Physical fit and panel integration
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a standard 3-pole MCCB footprint for DIN-rail or screw-mount panel installation. The front face carries an IP40 protection class, meaning tools and fingers are kept out but the device is not sealed against moisture.
Auxiliary and release options
This variant ships without auxiliary contacts and without an undervoltage release. It is pre-configured with a shunt trip (STL) design of auxiliary release, order code 3VA9688-0BL33 for the integrated trip unit — useful for remote tripping in emergency-stop or load-shedding circuits.