Fiber optic service entrance cables.

CFR · 2024-01-01 · US · Title 7

(a) (1) (ii) The optical waveguides are glass fibers having directly-applied protective coatings, and are called “fibers,” herein. These fibers may be assembled in either loose fiber bundles with a protective core tube, encased in several protective buffer tubes, in tight buffer tubes, or ribbon bundles with a protective core tube. (iii) Fillers, strength members, core wraps, and bedding tapes may complete the cable core. (iv) The core or buffer tubes containing the fibers and the interstices between the buffer tubes, fillers, and strength members in the core structure are filled with a suitable material or water swellable elements to exclude water. (v) The cable structure is completed by an extruded overall plastic jacket. A shield or armor or combination thereof may be included under the jacket. This jacket may have strength members embedded in it, in some designs. (vi) For rodent resistance or for additional protection with direct buried installations, it is recommended the use of armor under the outer jacket. (vii) For self-supporting cable the outer jacket may be extruded over the support messenger and cable core. (viii) For detection purposes, the cable may have toning elements embedded or extruded with the outer jacket. (2) The cable is fully color coded so that each fiber is distinguishable from every other fiber. A basic color scheme of twelve colors allows individual fiber identification. Colored tubes, binders, threads, striping, or markings provide fiber group ide

official document · source cfr-2024 · id 7:§ 1755.903