The Siemens 3VA9573-0JG23 is a SENTRON TA3.1 wire connector designed as a circular conductor terminal for internal use, accepting two cables per unit and sold in a pack of four. It's the factory-specified accessory for 3VA55, 3VA65, and 3VA66 molded-case circuit breakers — if you're building or maintaining a panel around those frames, this is the terminal that lands the big feeders.
Wire range and torque — what the numbers mean
Each terminal accepts copper or aluminum stranded conductors from 4/0 AWG up to 600 kcmil, and finely stranded copper the same range. For the common metric sizes, stranded 120–300 mm² and finely stranded 120–185 mm² both torque to 42.4 Nm. That's a serious lug — you're landing service-entrance or large feeder conductors, not control wiring. The stripped length spec is 1.0 inch, which matches standard heavy-duty crimp lug prep.
Control wire tap — a detail that saves a splice
The TA3.1 includes a control wire voltage tap-off on each terminal. That means you can pick off the line-side voltage for a shunt trip, auxiliary relay, or meter without adding a separate tap block or splicing into the main conductor. On a 3VA55/65/66 install, that's one less junction to torque-check and one less point of failure.