Learn what OSHA requires for temporary wiring on construction sites, from grounding and GFCI protection to overhead clearances and employer liability. Overhead fiber optic cable is mainly used for secondary trunk line and the following fiber optic cable lines. (FOA) was founded in 1995 to help develop the workforce to build the fiber optic networks to support a rapid expansion in communications and the Internet. These federal rules, enforced by. The scope of these guidelines is to inform public agencies, design engineers, contractors and inspectors of current Railroad standards and requirements concerning design and construction of temporary shoring. The fiber optic contractor should be able to work with the customer in each installation project. Article 590 addresses the practicality and execution issues that are inherent in temporary installations, thereby making them less time consuming to install and less time consuming to remove.