Typically, the joint box is installed on the inner side of the iron tower, ideally at a height between 8 and 10 meters above the ground. This placement not only provides uniformity along the line but also protects the fibers from environmental exposure while ensuring easy access for. The Fiber Optic Association, Inc. FO-VC2 JOINT USE - VERICAL MIDSPAN CLEARANCES 48. Use a suitable unwind device when pulling the cable from a drum. Adverse factors such as wind vibration, hurricanes, ice thickness, unstable operation caused by temperature, and possible lightning strikes and short circuits should be considered.