A cable storage cartridge and assembly for storing an excess length of cable. The cartridge includes a rectangular carriage frame and a spool rotatably disposed inside the carriage frame. The spool is comprised of a first spool member having a radius protection loop channel on its top surface and a second spool member. Together the first spool member and second spool member define a storage chamber. The storage chamber lies in a different plane than the loop channel of the first spool member. The first spool member defines transition openings for allowing the cable to pass from the loop channel to the storage chamber. Carriage frame includes detent and catch tabs for retaining the cartridge inside a cartridge housing.