submerged even several layers of polyethylene are found not to be totally water-
proof. In these conditions, an aluminum foil wrap is placed immediately under
the outer jacket (Figure 8.6).
Introduction to Fiber Optics
76
Figure 8.6
A waterproof
cable (strength
members
omitted for
clarity)
Ultraviolet protection
Sunlight and other sources of UV light tend to degrade many plastics, including
standard polyethylene and PVC, in the course of time. In most cases, making the
outer sheath from UV stabilized polyethylene is sufficient, but for extreme situ-
ations a metal-sheathed cable is used.
Hydrocarbons ...