The Siemens 3VA9604-0JC44 is a SENTRON TA4.4 circular conductor terminal — a wire connector designed for terminating up to four copper or aluminum cables in the 4/0 AWG to 600 kcmil range (stranded or finely stranded). It includes a control wire voltage tap-off, so you can pick off a lower-gauge control signal without a separate junction point. The terminal is specified for use with Siemens 3VA15 and 3VA25 molded-case circuit breakers.
Torque and strip-length specs
For stranded conductors 120–300 mm², the terminal torque is 42.4 Nm; finely stranded 120–185 mm² also gets 42.4 Nm. Strip length is 0.9 / 1.75 in — that's the insulation removal you need for a proper connection under the circular clamp.