The automatic cable reelers are supplied with an explosion proof polycarbonate junction box (K241EX) or Stainless Steel junction box (K247EX). A cable reeler is normally placed on the roof of a floating roof tank structure where it ensures electrical continuity between linear heat detection (LHD) sensor cable and the fire detection system during the upward and downward movement of the floating roof. The cable reeler ensures that the cable remains taught and prevents that cable from getting jammed in the moving parts of the roof.