[Al Skierkiewicz]

Jimmy,
The rules do follow the NEC. The Rockwell block can take two #10 or #12 wires per terminal. If the wire is stripped 5/8" and fully inserted into the block, the wires are well clamped by the block. Any less and the block will actually push the wires out over time. The ferrule mentioned above is a simple way to engage two wires that always will stay together in electrical designs and it makes insertion in mass production easier and less time consuming.