(3) Three continuous white or gray stripes along their length. (4) White or gray tape or markings at the terminations. 200.6(E) Neutral Conductors of Multiconductor Cables. Insulated neutral conductor ...

A specialty signal cable might have a bend radius of 24 in. and that would require a significantly larger pull box than what you’d use for a general wiring conductor of a similar-sized outer jacket.