Answered: Legal ways to repair motor wiring.

Unfortunately we had some of the pins break on the 393 motors. The rules state that identical VEX wires must be used, would that mean that severing the third cable on a 3 wire connector is also legal? Or would it be necessary to get the wires from a broken 393, or purchase the 2 wire extension cables?

This is not legal. It would be violation of <R15a>:

You are correct, this would be the legal way to repair your motor, as per