20 A line protection — what the ratings mean for fit
The Siemens SENTRON 3VA1020-4ED32-0HH0 is a 3-pole molded case circuit breaker rated for a continuous current Iu of 20 A, with a TM210 thermal-magnetic overcurrent release — the '210' designates the release family tuned for this frame size. The 20 A rating holds flat from 40 °C to 50 °C, then derates to 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C, so in a warm panel the usable current drops; size the load circuit for the actual ambient, not the nameplate. Breaking capacity runs 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. Those numbers tell you the fault current it can safely interrupt at each voltage level — critical for selectivity studies and SCCR compliance on the distribution board. The part carries a shunt trip (STL) auxiliary release and comes with 2 auxiliary switches plus 1 trip alarm switch HQ, so you get remote status feedback without an add-on module.
Panel integration and mounting
The breaker measures 76.2 mm wide, 130 mm high, and 70 mm deep. It mounts on a DIN rail or can be screw-fixed in a distribution panel. The IP40 front protection means it is suitable for enclosed panels where the front face is accessible but not exposed to washdown or dust ingress. The rated insulation voltage is 800 V, so it handles 690 V line-to-line circuits within the standard clearance and creepage margins.
Auxiliary and release configuration
This variant ships without an undervoltage release, without ground fault monitoring, without phase failure detection, and without communication function. The only auxiliary release fitted is the shunt trip (STL), which uses a separate voltage trigger to trip the breaker remotely. The integrated auxiliary trip order code is 3VA9688-0BL30 — order that separately if you need a replacement or spare trigger block. Mechanical endurance is rated at 15,000 cycles, which covers typical panel-switching duty on feeder or branch circuits.