When bringing down OPGW cable from substation structures, the routing should be straight and aesthetically pleasing, with an insulating fastener installed every 1.5-2.0m. Special attention must be paid to prevent the OPGW from contacting or rubbing against the tower structure.
Error Case
The drop-down OPGW cable should be supported using insulators between the cable and substation structure, or can be fixed with clamp-type insulating fasteners.
Insulator Support
The clearance between the drop-down cable and the most protruding parts of structural components (including flanges and crossarms) shall not be less than 5cm. Splice boxes and cable storage racks must be supported by insulators.
Drop-down fixing should use rigid or flexible clamps. Steel band-type clamps are prone to aging, breakage, and falling off, therefore the use of steel bands for fixing is strictly prohibited.
Qualified drop-down clamps must be selected. Some currently used drop-down clamps allow the OPGW fiber optic cable to slip out after the insulating pads age.
Aging of the rubber block caused the lead wire to come loose
During construction and installation, if the other hole of the clamp is not fitted with a cable of the same diameter, it can easily lead to the drop-down cable slipping out.
Drop-down clamps with a recessed structure that protects the perimeter of the insulating rubber blocks must be used.
When OPGW passes through structural crossarms during drop-down installation, fixed insulating clamps should be installed at the pass-through points to ensure the drop-down cable does not rub against the structural components.
Error cases lead to problems
