Friday, June 29, 2012

Outdoor Aerial Wire and Cable Installation - Moving Reel Method

Customers purchasing our many different types of outdoor wire and cable commonly ask how to lash cable to a messenger wire. One of the most common ways to do this is by using the moving reel method.

This method is used when reel carrying vehicles can drive most of the route. This method may be used when placing cable on a suspended strand or to an existing lashed cable and strand. Check out this cool lashing machine in action!

Each time a pole is reached the pulling stops. The cable guide (just in front of the lasher), and lasher get disconnected and moved past the pole. An expansion loop to the messenger is formed as temperature changes contracts the steel more then cables. Example below.

Before you get started let's go over some precautions.

* All personnel must be familiar with OSHA Occupational Safety and Hazard Act regulations.
* Follow the National Electrical Safety Code (NESC) for all installations.
* Cables installed near high voltage lines should be grounded.
* Cables that contain a corrugated steel tape should be grounded.
* The steel messenger shall be grounded.
* Make allowances for changing sag of the steel messenger wire in various weather conditions. Steel  messenger wire will expand and increase sag in warm weather.
* The steel messenger should be kept on one side of the poles (avoid zigzagging from one side of the pole to the other).
* Carefully inspect reels for imperfections such as broken flanges, cable crossovers, nails or anything that may cause damage as it is payed out.
* Follow the cable bend radius. Coax, phone and fiber wire and cable will differ.
* Never during the install should cable experience sags, bends and twist. A reduction in the cables transmission characteristics may not reveal itself till after installation.
* Do a pre-survey for splice locations, slack locations, cable storage requirements and possible obstructions like trees, roadways etc.
* You may want to consult an outside plant engineer.

As you can tell it sounds easy but lots of precautions do go into an installation of this type. I can hear my mother now, "Don't forget to put your helmet on!"

Thanks to Prysmian, OCC and Commscope.

"By Mercy Salinas"