(1) This section covers the requirements for filled buried wires intended for direct burial as a subscriber drop and/or distribution wire.

(2) The number of pairs and gauge size of conductors which are used within the RUS program are provided in the following table:

(3) All wires sold to RUS borrowers for projects involving RUS loan funds under this section must be accepted by RUS Technical Standards Committee “A” (Telephone). For wires 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.

(4) Materials, manufacturing techniques, or wire designs not specifically addressed by this section may be allowed if accepted by RUS. Justification for acceptance of modified materials, manufacturing techniques, or wire designs must be provided to substantiate product utility and long term stability and endurance.

(5) The American National Standards Institute/Electronic Industries Association (ANSI/EIA) 359-A-84, EIA Standard Colors for Color Identification and Coding, 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. Copies of ANSI/EIA 359-A-84 are available for inspection during normal business hours at RUS, room 2845, U.S Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from EIA, 2001 Pennsylvania Avenue, NW., suite 900, Washington, DC 20006, telephone number (202) 457-4966.

(6) American Society for Testing and Materials specifications (ASTM) A 505-87, Standard Specification for Steel, Sheet and Strip, Alloy, Hot-Rolled and Cold-Rolled, General Requirements for; ASTM B 3-90, Standard Specification for Soft or Annealed Copper Wire; ASTM B 193-87, Standard Test Method for Resistivity of Electrical Conductor Materials; ASTM B 224-91, Standard Classification of Coppers; ASTM B 694-86, Standard Specification for Copper, Copper Alloy, and Copper-Clad Stainless Steel Sheet and Strip for Electrical Cable Shielding; ASTM D 150-87, Standard Test Methods for A-C Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials; ASTM D 257-91, Standard Test Methods for D-C Resistance or Conductance of Insulating Materials; ASTM D 1238-90b, Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer; ASTM D 1248-84(1989), Standard Specification for Polyethylene Plastics Molding and Extrusion Materials; ASTM D 1535-89, Standard Test 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 4101-82(1988), Standard Specification for Propylene Plastic Injection and Extrusion Materials; ASTM D 4565-90a, Standard Test Methods for Physical and Environmental Performance Properties of Insulations and Jackets for Telecommunications 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 Materials; ASTM D 4872-88, Standard Test Method for Dielectric Testing of Wire and Cable Filling Compounds; ASTM E 8-91, Standard Test Methods of Tension Testing of Metallic Materials; 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) and 1 CFR part 51. Copies of the ASTM standards are available for inspection during normal business hours at RUS, room 2845, U.S. Department Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from ASTM, 1916 Race Street, Philadelphia, Pennsylvania 19103-1187, telephone number (215) 299-5585.

(1) Each conductor must be a solid round wire of commercially pure annealed copper. Conductors must meet the requirements of the American Society for Testing and Materials (ASTM) B 3-90 except that requirements for Dimensions and Permissible Variations are waived and elongation requirements are superseded by this section.

(2) The minimum conductor elongation in the final wire must comply with the following limits when tested in accordance with ASTM E 8-91.

(3) Joints made in conductors during the manufacturing process may be brazed, using a silver alloy solder and nonacid flux, or they may be welded using either an electrical or cold welding technique. In joints made in uninsulated conductors, the two conductor ends must be butted. Splices made in insulated conductors need not be butted but may be joined in a manner acceptable to RUS.

(4)

(5) Each conductor must be insulated with either a colored, solid, insulating grade, high density polyethylene or crystalline propylene/ethylene copolymer or with a solid natural primary layer and a colored, solid outer skin using one of the insulating materials listed in paragraphs (b)(5)(i) through (b)(5)(ii) of this section.

(6) All conductors in any single length of wire must be insulated with the same type of material.

(7) A permissible overall performance level of faults in conductor insulation must average not greater than one fault per 12,000 conductor meters (40,000 conductor feet) for each gauge of conductor.

(8) Repairs to the conductor insulation during manufacturing are permissible. The method of repair must be accepted by RUS prior to its use. The repaired insulation must be capable of meeting the relevant electrical requirements of this section.

(9) All repaired sections of insulation must be retested in the same manner as originally tested for compliance with paragraph (b)(7) of this section.

(10) Colored insulating material removed from or tested on the conductor, from a finished wire, must be capable of meeting the following performance requirements:

(11) Testing procedures. The procedures for testing the insulation samples for compliance with paragraph (b)(10) of this section must be as follows.

(12) Other methods of testing may be used if acceptable to RUS.

(1) The insulation must be colored to identify:

(2) The colors to be used to provide identification of the tip and ring conductor of each pair are shown in the following table:

(3) Standards of color. The colors of the insulated conductors supplied in accordance with this section are specified in terms of the Munsell Color System (ASTM D 1535-89) and must comply with the “Table of Wire and Cable Limit Chips” as defined in ANSI/EIA-359-A-84. (Visual color standards meeting these requirements may be obtained directly from the Munsell Color Company, Inc., 2441 North Calvert Street, Baltimore, Maryland 21218).

(4) Positive identification of the tip and ring conductors of each pair by marking each conductor of a pair with the color of its mate is permissible. The method of marking must be accepted by RUS prior to its use.

(5) Other methods of providing positive identification of the tip and ring conductors of each pair may be employed if accepted by RUS prior to its use.

(6) The insulated conductors must be twisted into pairs.

(7) In order to provide sufficiently high crosstalk isolation, the pair twists must be designed to enable the wire to meet the capacitance unbalance and the crosstalk loss requirements of paragraphs (m)(2), (m)(3), and (m)(4) of this section.

(8) The average length of pair twists in any pair in the finished wire, when measured on any 3 meter (m) (10 foot(ft)) length, must not exceed 152 mm (6 in.).

(9) An alternative method of forming the two pair wire is the use of a star-quad configuration.

(1) Twisted pairs or star-quad configuration must be assembled in such a way as to form a substantially cylindrical group.

(2) The filling compound must be applied to the wire core in such a way as to provide a completely filled core as is commercially practical.

(3) If desired for manufacturing reasons, white or colored binders of nonhygroscopic and nonwicking material may be applied over the core.

(1) After or during the stranding operation and prior to application of the optional core wrap and inner jacket, a homogeneous filling compound free of agglomerates must be applied to the wire core. The compound must be as nearly colorless as is commercially feasible and consistent with the end product requirements and pair identification.

(2) The filling compound must be free from dirt, metallic particles, and other foreign matter. It must be applied in such a way as to fill the space within the wire core.

(3) The filling compound must be nontoxic and present no dermal hazards.

(4) The filling compound must exhibit the following dielectric properties at a temperature of 23 ±3 °C when measured in accordance with ASTM D 150-87 or ASTM D 4872-88.

(5) The volume resistivity must not be less than 10¹² ohm-cm at a temperature of 23 ±3 °C when measured in accordance with ASTM D 257-91 or ASTM D 4872-88.

(6) The individual wire manufacturer must satisfy RUS that the filling compound selected for use is suitable for its intended application. The filling compound must be compatible with the wire components when tested in accordance with ASTM D 4568-86 at a temperature of 80 °C.

(1) When a core wrap is used, it must consist of a layer of nonhygroscopic and nonwicking dielectric material. The wrap must be applied with an overlap.

(2) The core wrap must provide a sufficient heat barrier to prevent visible evidence of conductor insulation deformation or adhesion between conductors, caused by adverse heat transfer during the inner jacketing operation.

(3) If required for manufacturing reasons, white or colored binders of nonhygroscopic and nonwicking material may be applied over the core wrap.

(4) Sufficient filling compound must be applied to the core wrap that voids or air spaces existing between the core and inner side of the core wrap are minimized.

(1) An inner jacket must be applied over the core and/or core wrap.

(2) The jacket must be free from holes, splits, blisters, or other imperfections and must be as smooth and concentric as is consistent with the best commercial practice.

(3) The inner jacket material and test requirements must be as specified for the outer jacket material per paragraphs (j)(3) through (j)(5)(iv) of this section.

(4) The inner jacket thickness at any point must not be less than 0.5 mm (0.020 in.). The thickness must be determined from measurements on 50 mm (2 in.) samples taken not less than 0.3 m (1 ft) from either end of the wire. The average must be determined from 4 readings taken approximately 90 °apart on any cross section of the samples. The maximum and minimum points must be determined by exploratory measurements. The maximum thickness minus the minimum thickness at any cross section must not exceed 43 percent of the average thickness at that cross section.

(1) Sufficient flooding compound must be applied on all sheath interfaces so that voids and air spaces in these areas are minimized.

(2) The flooding compound must be compatible with the jacket when tested in accordance with ASTM D 4568-86 at a temperature of 80 °C. The floodant must exhibit adhesive properties sufficient to prevent jacket slip when tested in accordance with the requirements of appendix A, paragraph (III)(5), of this section.

(3) The individual wire manufacturer must satisfy RUS that the flooding compound selected for use is acceptable for the application.

(1) A shield must be applied either longitudinally or helically over the inner jacket.

(2) The overlap for longitudinally applied shields must be a minimum of 2 mm (0.075 in.) The overlap for helically applied shields must be a minimum of 23 percent of the tape width.

(3) General requirements for application of the shielding material are as follows:

(4) The following materials are acceptable for use as wire shielding:

(1) The outer jacket must provide the wire with a tough, flexible, protective covering which can withstand exposure to sunlight, to atmospheric temperatures and stresses reasonably expected in normal installation and service.

(2) The jacket must be free from holes, splits, blisters, or other imperfections and must be as smooth and concentric as is consistent with the best commercial practice.

(3) The raw material used for the outer jacket must be one of the five types listed in paragraphs (j)(3)(i) through (j)(3)(v) of this section. The raw material must contain an antioxidant to provide long term stabilization and the materials must contain a 2.60 ±0.25 percent concentration of furnace black to provide ultraviolet shielding. Both the antioxidant and furnace black must be compounded into the material by the raw material supplier.

(4) The outer jacketing material removed from or tested on the wire must be capable of meeting the following performance requirements:

(5) Testing procedures. The procedures for testing the jacket samples for compliance with paragraph (j)(4) of this section must be as follows:

(6) Jacket thickness. The minimum jacket thickness must be 0.64 mm (0.025 in.) except that the minimum thickness over the sheath slitting cord, if present, must be 0.46 mm (0.018 in.). The minimum point must be determined by exploratory measurements. The average thickness at any cross section must be determined from four readings including the minimum point, taken approximately 90 °apart. The thickness measurement must exclude any jacket material that has formed into the corrugation. The maximum thickness at any cross section must not be greater than 155 percent of the minimum thickness.

(7) Eccentricity. The eccentricity of the jacket must not exceed 43 percent when calculated using the formula as follows:

(1) Sheath slitting cords may be used in the wire structure at the option of the manufacturer.

(2) When a sheath slitting cord is used it must be nonhygroscopic and nonwicking, continuous throughout a length of wire, and of sufficient strength to open the sheath without breaking the cord.

(3) Sheath slitting cords must be capable of consistently slitting the jacket(s) and/or shield for a continuous length of 0.6 m (2 ft) when tested in accordance with the procedure specified in appendix B of this section.

(1) Each length of wire must be permanently identified as to manufacturer and year of manufacture.

(2) The number of conductor pairs and their gauge size must be marked on the jacket.

(3) The marking must be printed on the jacket at regular intervals of not more than 1.5 m (5 ft).

(4) An alternative method of marking may be used if accepted by RUS prior to its use.

(5) The completed wire must have sequentially numbered length markers in FEET OR METERS at regular intervals of not more than 1.5 m (5 ft) along the outside of the jacket.

(6) The method of length marking must be such that for any single length of wire, continuous sequential numbering must be employed.

(7) The numbers must be dimensioned and spaced to produce good legibility and must be approximately 3 mm (0.125 in.) in height. An occasional illegible marking is permissible if there is a legible marking located not more than 1.5 m (5 ft) from it.

(8) The method of marking must be by means of suitable surface markings producing a clear, distinguishable, contrasting marking acceptable to RUS. Where direct or transverse printing is employed, the characters should be indented to produce greater durability of marking. Any other method of length marking must be acceptable to RUS as producing a marker suitable for the field. Size, shape and spacing of numbers, durability, and overall legibility of the marker will be considered in acceptance of the method.

(9) The accuracy of the length marking must be such that the actual length of any wire section is never less than the length indicated by the marking and never more than one percent greater than the length indicated by the marking.

(10) The color of the initial marking must be white or silver. If the initial marking fails to meet the requirements of the preceding paragraphs, it will be permissible to either remove the defective marking and re-mark with the white or silver color or leave the defective marking on the wire and re-mark with yellow. No further re-marking is permitted. Any re-marking must be on a different portion of the wire circumference than any existing marking when possible and have a numbering sequence differing from any other existing marking by at least 5,000.

(11) Any reel of wire which contains more than one set of sequential markings must be labeled to indicate the color and sequence of marking to be used. The labeling must be applied to the reel and also to the wire.

(1) Mutual capacitance and conductance.

(2) Pair-to-pair capacitance unbalance. The capacitance unbalance between any pair of the completed wire must not exceed 145 picofarad/kilometer (pF/km) (80 picofarad/1000 ft (pF/1000 ft)) when tested in accordance with ASTM D 4566-90 at a frequency of 1.0 ±0.1 kHz and a temperature of 23 ±3 °C.

(3) Pair-to-ground capacitance unbalance -

(4) Far-end crosstalk loss.

(i) The output-to-outputfar-end crosstalk loss (FEXT) between any pair combination of a completed wire when measured in accordance with ASTM D 4566-90 at a test frequency of 150 kHz must not be less than 58 decibel/ kilometer (dB/km) (63 decibel/1000 ft). If the loss K_o at a frequency F_o for length L_o is known, then K_x can be determined for any other frequency F_x or length L_x by:

(5) Attenuation. The attenuation of any individual pair on any reel of wire must not exceed the following limits when measured at or corrected to a temperature of 20 ±1 °C and a test frequency of 150 kHz. The test must be conducted in accordance with ASTM D 4566-90.

(6) Insulation resistance. Each insulated conductor in each length of completed wire, when measured with all other insulated conductors and the shield grounded, must have an insulation resistance of not less than 1600 megohm-kilometer (1000 megohm-mile) at 20 ±1 °C. The measurement must be made in accordance with the procedures of ASTM D 4566-90.

(7) High voltage test.

(8) Conductor resistance. The dc resistance of any conductor must be measured in the completed wire in accordance with ASTM D 4566-90 and must not exceed the following values when measured at or corrected to a temperature of 20 ±1 °C.

(9) Resistance unbalance.

(1) Defective wire. Pairs in each length of wire will not be permitted to have either a ground, cross, short or open circuit condition.

(2) Wire breaking strength. The breaking strength of the completed wire must not be less than 890 newtons (200 pound-force) when tested in accordance with ASTM D 4565-90a using a jaw separation speed of 25 mm/min (1.0 in./min).

(3) Wire bending test. The completed wire must be capable of meeting the requirements of ASTM D 4565-90a after conditioning at −20 ±2 °C and at 23 ±2 °C.

(4) Water penetration test.

(5) Compound flow test. The completed wire must be capable of meeting the compound flow test specified in ASTM D 4565-90a when exposed for a period of 24 hours at a temperature of 80 ±1 °C. At the end of this test period, there must be no evidence of flowing or dripping of compound from either the core or sheath interfaces.

(1) The tests described in appendix A of this section are intended for acceptance of wire designs and major modifications of accepted designs. RUS decides what constitutes a major modification. These tests are intended to show the inherent capability of the manufacturer to produce wire products having long life and stability.

(2) For initial acceptance, the manufacturer must submit:

(3) For requalification acceptance, the manufacturer must submit an original signature certification that the product fully complies with each section of the specification, excluding the Qualification Section, and a certification that the product does or does not comply with the domestic origin manufacturing provisions of the “Buy American” requirements of the Rural Electrification Act of 1938 (7 U.S.C. 901 et seq.) for acceptance by June 30 every three years. The required data and certification must have been gathered within 90 days of the submission.

(4) Initial and requalification acceptance requests should be addressed to: Chairman, Technical Standards, Committee “A” (Telephone), Telecommunications Standards Division, Rural Utilities Service, Washington, DC 20250-1500.

(5) Tests on 100 percent of completed wire.

(6) Capability tests. Tests on a quality assurance basis must be made as frequently as is required for each manufacturer to determine and maintain compliance with:

(1) Each manufacturer must maintain suitable summary of records for a period of at least 3 years for all electrical and physical tests required on completed wire by this section as set forth in paragraphs (o)(5) and (o)(6) of this section. The test data for a particular reel shall be in a form that it may be readily available to the purchaser or to RUS upon request.

(2) Measurements and computed values must be rounded off to the number of places of figures specified for the requirement according to ASTM E 29-90.

(1) Repairs to the inner jacket and shield are not permitted in wire supplied to the end user under this section.

(2) Minor defects in the outer jackets (defects having a dimension of 3 mm (0.125 in.) or less in any direction) may be repaired by means of heat fusing in accordance with good commercial practices utilizing sheath grade compound.

(1) The wire must be shipped on reels. The diameter of the drum must be large enough to prevent damage to the wire from reeling or unreeling. The reels must be substantial and so constructed as to prevent damage to the wire during shipment and handling.

(2) The thermal wrap must comply with the requirements of appendix C of this section. When a thermal reel wrap is supplied, the wrap must be applied to the reel and must be suitably secured in place to minimize thermal exposure to the wire during storage and shipment. The use of the thermal reel wrap as a means of reel protection will be at the option of the manufacturer unless specified by the end user.

(3) The outer end of the wire must be securely fastened to the reel head so as to prevent the wire from becoming loose in transit. The inner end of the wire must be securely fastened in such a way as to make it readily available if required for electrical testing. Spikes, staples, or other fastening devices which penetrate the wire jacket must not be used. The method of fastening the wire ends must be accepted by RUS prior to it being used.

(4) Each length of wire must be wound on a separate reel unless otherwise specified or agreed to by the purchaser.

(5) Each reel must be plainly marked to indicate the direction in which it should be rolled to prevent loosening of the wire on the reel.

(6) Each reel must be stenciled or labeled on either one or both sides with the name of the manufacturer, year of manufacture, actual shipping length, an inner and outer end sequential length marking, description of the wire, reel number and the RUS wire designation:

(7) Both ends of the filled buried wire, manufactured to the requirements of this section, must be equipped with end caps which are acceptable to RUS.