A. For use in factory wiring only, power or control circuits.
B. Crimped with an appropriate tool as recommended by the ferrule manufacturer before terminating in terminal blocks, wire connectors, or end-product terminals (such as starters, etc.).
C. Sized in diameter appropriate for the number of wires, wire type (stranded/solid) and wire size as recommended by the ferrule manufacturer such that the crimp results in a reliable connection.
D.  Constructed such that the length of the wires held captive by the ferrules are trimmed, if necessary, and that there are no excess live parts, which can result in the reduction of electrical spacings.

(*) UL Bulletin dated January 17, 2013 titled “Use of Wiring Ferrules and UPS Equipment in Industrial Control Panels”.