Each pack of cable kits will tension one end of a run of cable. If your railing system is 36” tall, you’ll generally need a 10 pack of kits for each end of the run. You’ll need an 11 pack for a 39” system, and a 12 pack for a 42” system. This allows the cable to be spaced less than 4” apart, which is required to meet code.
Wood kits allow you to create a cable railing system from existing wooden posts. Wood posts generally need to be placed every 4 feet, with cable spaced 3 ⅛” apart to satisfy code requirements.