Rockwell Automation 1786-series ControlNet Fiber Media Planning and Installation Guide - Manual (Page 50)

50 Rockwell Automation Publication CNET-IN001C-EN-P - October 2011
Chapter 3 Guidelines for Fiber-optic Installation
Direct Burial Installation
Some applications call for a direct burial installation. Direct burial installation
requires some special considerations that aren’t necessary for other pulled
applications. These guidelines are designed to prevent hazards such as freezing
water, crushing forces, ground disruption from construction, and rodents.
Use the following guidelines to help you plan your direct burial installation.
• Use cable specifically designed for direct burial.
• Use heavy duty armor cables buried directly into the ground.
• Bury the cable between 1…1.2 m (36…48 in.) deep.
• Use gel filling, metal sheathing, and armoring when possible.
• Use loose-tube cable constructions where uneven pulling forces are
a problem.
Open Trench Installation
Use these steps as a guide for installing fiber-optic cable by using an open
trench method.
1. Maintain minimum tension on the cable as it rolls over the guide rollers
and through the guide shoot.
2. Consider methods of placement like boring or creating a conduit when
your installation intersects with objects like streets, sidewalks, or
landscaping.
3. Maintain at least a 1 m (39 in.) separation when your fiber-optic cable is
placed in proximity to an existing power cable.
4. Use some form of mechanical protection (steel pipe, cement conduit, and
so forth) when adequate earth cover cannot be maintained in
your application.
IMPORTANT Do not pull the cable in excess of its maximum allowable
installation tension as specified in the cable manufacturer’s
specifications.