1、From the U.S. Government Printing Office via GPO AccessCITE: 7CFR1755.900 TITLE 7-AGRICULTURE CHAPTER XVII-RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTUREPART 1755-TELECOMMUNICATIONS STANDARDS AND SPECIFICATIONS FOR MATERIALS, EQUIPMENT AND CONSTRUCTION-Table of ContentsSec. 1755.900 RUS specific
2、ation for filled fiber optic cables.（a） Scope. （1） This section covers the requirement for filled fiber optic cables intended for aerial installation either by attachment to a support strand or by an integrated self-supporting arrangement, for underground application by placement in a duct, or for b
3、uried installations either by trenching or by direct plowing. （i） 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
4、 buffer tubes, or in tight buffer tubes. （ii） Fillers, strength members, core wraps, and bedding tapes may complete the cable core. （iii） 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
5、 suitable material to exclude water. （iv） The cable structure is completed by an extruded overall plastic jacket. This jacket may have strength members embedded in it, in some designs. （v） Buried installation requires an armor under the outer jacket. （vi） For self-supporting cable the outer jacket m
6、ay be extruded over the support messenger and cable core. （2） The cable is fully color coded so that each fiber is distinguishable from every other fiber. A basic color scheme of twenty-four colors allows individual fiber identification. Colored tubes, binders, threads, stripings, or markings provid
7、e fiber group identification. （3） Cable manufactured to this section must demonstrate compliance with the qualification testing requirements to ensure satisfactory end-use performance characteristics for the intended applications. （4） Optical cable designs not specifically addressed by this section
8、may be allowed if accepted by RUS. Justification for acceptance of a modified design must be provided to substantiate product utility and long term stability and endurance. （5） All cables sold to RUS borrowers for projects involving RUS loan funds under this section must be accepted by RUS Technical
9、 Standards Committee A （Telephone）. For cables manufactured to the specification of this section, all design changes to an accepted design must be submitted for acceptance. RUS will be the sole authority on what constitutes a design change. （6） The American National Standard Institute/Institute of E
10、lectrical and Electronics Engineers, Inc （ANSI/IEEE）, 1993 National Electrical Safety Code （NESC） referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552（a） and 1 CFR part 51.
11、 Copies of ANSI/IEEE 1993 NESC are available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-1500 or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. Copies are available from IEEE Ser
12、vice Center, 445 Hoes Lane, Piscataway, NJ 08854, telephone number 1 （800） 678-4333. （7） American Society for Testing and Materials Specifications （ASTM） A 640-91, Standard Specification for Zinc-Coated Steel Strand for Messenger Support of Figure 8 Cable; ASTM B 736-92a, Standard Specification for
13、Aluminum, Aluminum Alloy, and Aluminum-Clad Steel Cable Shielding Stock; ASTM D 1238-90b, Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer; ASTM D 1248-84 （1989）, Standard Specification for Polyethylene Plastic Molding and Extrusion Materials, ASTM D 1535-89, Standard T
14、est Method for Specifying Color by the Munsell System; ASTM D 3349-86, Standard Test Method for Absorption Coefficient of Carbon Black Pigmented Ethylene Plastic; ASTM D 4565-90a, Standard Test Methods for Physical and Environmental Performance Properties of Insulations and Jackets for Telecommunica
15、tions Wire and Cable; ASTM D 4566-90, Standard Test Methods for Electrical Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable; ASTM D 4568-86, Standard Test Methods for Evaluating Compatibility Between Cable Filling and Flooding Compounds and Polyolefin Cable Mat
16、erials; and ASTM E 29-90, Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications, referenced in this section are incorporated by reference by RUS. These incorporations by references were approved by the Director of the Federal Register in accordance with 5 U.S.C. 552（a）
