Far-end crosstalk loss.
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 Ko at a frequency Fo for length Lo is known, then Kx can be determined for any other frequency Fx or length Lx by:
(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 Ko at a frequency Fo for length Lo is known, then Kx can be determined for any other frequency Fx or length Lx 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.
(i) In each length of completed wire, the insulation between conductors when tested in accordance with ASTM D 4566–90 must withstand for 3 seconds a direct current (dc) potential whose value is not less than:
(A) 5.0 kilovolts for 22-gauge conductors; and
(B) 4.0 kilovolts for 24-gauge conductors.
(ii) In each length of completed wire, the dielectric strength between the shield and all conductors in the core must be tested in accordance with ASTM D 4566–90 and must withstand, for 3 seconds, a dc potential whose value is not less than 20 kilovolts.
(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.
(i) The difference in dc resistance between the two conductors of any pair in the completed wire must not exceed 5.0 percent when measured in accordance with the procedures of ASTM D 4566–90.
(ii) The resistance unbalance between tip and ring conductors shall be random with respect to the direction of unbalance. That is, the resistance of the tip conductors shall not be consistently higher with respect to the ring conductors and vice versa.
(n) Mechanical requirements—(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.
(i) A one meter (3 ft) length of completed wire must be stabilized at 23 ±2 °C and tested in accordance with ASTM D 4565–90a using a one meter (3 ft) water head over the sample or placed under the equivalent continuous pressure for one hour.
(ii) After the one hour period, there must be no water leakage in the sheath interfaces, under the core wrap or between any insulated conductors in the core.
(iii) If water leakage is detected in the first sample, one 3 m (10 ft) additional adjacent sample from the same reel of wire must be tested in accordance with paragraph (n)(4)(ii) of this section. If the second sample exhibits water leakage, the entire reel of wire is to be rejected. If the second sample exhibits no leakage, the entire reel of wire is considered acceptable.
(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.
(o) Acceptance testing and extent of testing.
(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:
(i) An original signature certification that the product fully complies with each requirement of this section;
(ii) Qualification Test Data, per appendix A of this section;
(iii) To periodic plant inspections;
(iv) 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.);
(v) Written user testimonials concerning performance of the product; and
(vi) Other nonproprietary data deemed necessary by the Chief, Outside Plant Branch (Telephone).
(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. (i) The shield of each length of wire must be tested for continuity using the procedures of ASTM D 4566–90.
(ii) Dielectric strength between all conductors and the shield must be tested to determine freedom from grounds in accordance with paragraph (m)(7)(ii) of this section.
(iii) Each conductor in the completed wire must be tested for continuity using the procedures of ASTM D 4566–90.
(iv) Dielectric strength between conductors must be tested to ensure freedom from shorts and crosses in accordance with paragraph (m)(7)(i) of this section.
(v) The average mutual capacitance must be measured on all wires.
(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:
(i) Performance requirements for conductor insulation and jacket material;
(ii) Performance requirements for filling and flooding compounds;
(iii) Sequential marking and lettering;
(iv) Capacitance unbalance and crosstalk;
(v) Insulation resistance;
(vi) Conductor resistance and resistance unbalance;
(vii) Wire bending and wire breaking strength tests;
(viii) Mutual conductance and attenuation; and
(ix) Water penetration and compound flow tests.
(p) Summary of records of electrical and physical tests.
(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.
(q) Manufacturing irregularities.
(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.
(r) Preparation for shipment.
(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.
(I) The test procedures described in this appendix are for qualification of initial designs and major modifications of accepted designs. Included in (V) of this appendix are suggested formats that may be used in submitting test results to RUS.
(II) Sample Selection and Preparation.
(1) All testing must be performed on lengths removed sequentially from the same 3 pair, 22 gauge jacketed wire. This wire must not have been exposed to temperatures in excess of 38 °C since its initial cool down after sheathing. The lengths specified are minimum lengths and if desirable from a laboratory testing standpoint longer lengths may be used.
(a) Length A shall be 10 ±0.2 meters (33 ±0.5 feet) long and must be maintained at 23 ±3 °C. One length is required.
(b) Length B shall be 12 ±0.2 meters (40 ±0.5 feet) long. Prepare the test sample by removing the inner and outer jacket, shield, and core wrap, if present, for a sufficient distance on both ends to allow the insulated conductors to be flared out. Remove sufficient conductor insulation so that appropriate electrical test connections can be made at both ends. Coil the specimen with a diameter of 15 to 20 times its sheath diameter. Three lengths are required.
(c) Length C shall be one meter (3 feet) long. Four lengths are required.
(d) Length D shall be 300 millimeters (1 foot) long. Four lengths are required.
(e) Length E shall be 600 millimeters (2 feet) long. Four lengths are required.
(f) Length F shall be 3 meters (10 feet) long and must be maintained at 23 ±3 °C for the duration of the test. Two lengths are required.
(2) Data Reference Temperature. Unless otherwise specified, all measurements shall be made at 23 ±3 °C.
(III) Environmental Tests—(1) Heat Aging Test—(a) Test Samples. Place one sample each of lengths B, C, D, and E in an oven or environmental chamber. The ends of sample B must exit from the chamber or oven for electrical tests. Securely seal the oven exit holes.
(b) Sequence of Tests. After conditioning the samples are to be subjected to the following tests:
(i) Water Immersion Test outlined in (III)(2) of this appendix;
(ii) Water Penetration Test outlined in (III)(3) of this appendix; .
(iii) Insulation Compression Test outlined in (III)(4) of this appendix; and
(iv) Jacket Slip Strength Test outlined in (III)(5) of this appendix.
(c) Initial Measurements.
(i) For sample B, measure the open circuit capacitance and conductance for each pair at 1 and 150 kilohertz and the attenuation at 150 kilohertz after conditioning the sample at the data reference temperature for 24 hours. Calculate the average and standard deviation for the data of the 3 pairs on a per kilometer (per mile) basis.
(ii) The attenuation at 150 kilohertz may be calculated from open circuit admittance (Yoc) and short circuit impedance (Zsc) or may be obtained by direct measurement of attenuation.
(iii) Record on suggested formats attached in (V) of this appendix or on other easily readable formats.
(d) Heat Conditioning.
(i) Immediately after completing the initial measurements, condition the sample for 14 days at a temperature of 65 ±2 °C.
(ii) At the end of this period note any exudation of filling compound. Measure and calculate the parameters given in (III)(1)(c) of this appendix. Record on suggested formats attached in (V) of this appendix or on other easily readable formats.
(iii) Cut away and discard a one meter (3 foot) section from each end of length B.
(e) Overall Electrical Deviation.
(i) Calculate the percent change in all average parameters between the final parameters after conditioning with the initial parameters in (III)(1)(c) of this appendix.
(ii) The stability of the electrical parameters after completion of this test must be within the following prescribed limits:
(A) Capacitance. The average mutual capacitance must be within 5 percent of its original value;
(B) The change in average mutual capacitance must be less than 5 percent over the frequency range of 1 to 150 kilohertz;
(C) Conductance. The average mutual conductance must not exceed 2 micromhos/kilometer (3.3 micromhos/mile) at a frequency of 1 kilohertz; and
(D) Attenuation. The attenuation must not have increased by more than 5 percent over its original value.
(2) Water Immersion Electrical Test—(a) Test Sample Selection. The 10 meter (33 foot) section of length B must be tested.
(b) Test Sample Preparation. Prepare the sample by removing the inner and outer jacket, shield, and core wrap, if present, for a sufficient distance to allow one end to be accessed for test connections. Cut out a series of 2.5 millimeter by 13 millimeter (0.1 inch by 0.5 inch) rectangular slots along the test sample, at 300 millimeter (1 foot) intervals progressing successively 90 degrees around the circumference of the wire. Assure that the wire core is exposed at each slot by slitting the inner jacket and core wrap if present. Place the prepared sample in a dry vessel which when filled will maintain a one meter (3 foot) head of water over 6 meters (20 feet) of uncoiled wire. Extend and fasten the ends of the wire so they will be above the water line and the pairs are rigidly held for the duration of the test.
(c) Capacitance and Conductance Testing. Measure the initial values of mutual capacitance and conductance of all pairs in each wire at a frequency of 1 kilohertz before filling the vessel with water. Be sure the wire shield is grounded to the test equipment. Fill the vessel until there is a one meter (3 foot) head of water on the wires.
(i) Remeasure the mutual capacitance and conductance after the wires have been submerged for 24 hours and again after 30 days.
(ii) Record each sample separately on the suggested formats attached in (V) of this appendix or on other easily readable formats.
(d) Overall Electrical Deviation.
(i) Calculate the percent change in all average parameters between the final parameters after conditioning with the initial parameters in (III)(2)(c) of this appendix.
(ii) The stability of the electrical parameters after of the test must be within the following prescribed limits:
(A) Capacitance. The average mutual capacitance must be within 5 percent of its original value; and
(B) Conductance. The average mutual conductance must not exceed 2 micromhos/kilometer (3.3 micromhos/mile) at a frequency of 1 kilohertz.
(3) Water Penetration Testing.
(a) A watertight closure must be placed over the jacket of length C. The closure must not be placed over the jacket so tightly that the flow of water through preexisting voids or air spaces is restricted. The other end of the sample must remain open.
(b) Test per Option A or Option B.
(i) Option A. Weigh the sample and closure prior to testing. Fill the closure with water and place under a continuous pressure of 10 ±0.7 kilopascals (1.5 ±0.1 pounds per square inch gauge) for one hour. Collect the water leakage from the end of the test sample during the test and weigh to the nearest 0.1 gram. Immediately after the one hour test, seal the ends of the wire with a thin layer of grease and remove all visible water from the closure, being careful not to remove water that penetrated into the core during the test. Reweigh the sample and determine the weight of water that penetrated into the core. The weight of water that penetrated into the core must not exceed 1 gram.
(ii) Option B. Fill the closure with a 0.2 gram sodium fluorscein per liter water solution and apply a continuous pressure of 10 ±0.7 kilopascals (1.5 ±0.1 pounds per square inch gauge) for one hour. Catch and weigh any water that leaks from the end of the wire during the one hour period. If no water leaks from the sample, carefully remove the water from the closure. Then carefully remove the outer jacket, shield, inner jacket and core wrap, if present, one at a time, examining with an ultraviolet light source for water penetration. After removal of the inner jacket and core wrap, if present, carefully dissect the core and examine for water penetration within the core. Where water penetration is observed, measure the penetration distance. The distance of water penetration into the core must not exceed 127 millimeters (5.0 inches).
(4) Insulation Compression Test.
(a) Test Sample D. Remove inner and outer jacket, shield, and core wrap, if present, being careful not to damage the conductor insulation. Remove one pair from the core and carefully separate, wipe off core filler and straighten the insulated conductors. Retwist the two insulated conductors together under sufficient tension to form 10 evenly spaced 360 degree twists in a length of 100 millimeters (4 inches).
(b) Sample Testing. Center the mid 50 millimeters (2 inches) of the twisted pair between two smooth rigid parallel metal plates measuring 50 millimeters (2 inches) in length or diameter. Apply a 1.5 volt direct current potential between the conductors, using a light or buzzer to indicate electrical contact between the conductors. Apply a constant load of 67 newtons (15 pound-force) on the sample for one minute and monitor for evidence of contact between the conductors. Record results on suggested formats attached in (V) of this appendix or on other easily readable formats.
(5) Jacket Slip Strength Test—(a) Sample Selection. Test sample E from (III)(1)(a) of this appendix.
(b) Sample Preparation. Prepare test sample in accordance with the procedures specified in ASTM D 4565–90a.
(c) Sample Conditioning and Testing. Remove the sample from the tensile tester prior to testing and condition for one hour at 50 ±2 °C. Test immediately in accordance with the procedure specified in ASTM D 4565–90a. A minimum outer jacket slip strength of 67 newtons (15 pound-force) is required. Record the load attained.
(6) Humidity Exposure.
(a) Repeat steps (III)(1)(a) through (III)(1)(c)(iii) of this appendix for separate set of samples B, C, D and E which have not been subjected to prior environmental conditioning.
(b) Immediately after completing the measurements, expose the test sample to 100 temperature cyclings. Relative humidity within the chamber must be maintained at 90 ±2 percent. One cycle consists of beginning at a stabilized chamber and test sample temperature of 52 ±1 °C, increasing the temperature to 57 ±1 °C, allowing the chamber and test samples to stabilize at this level, then dropping the temperature back to 52 ±1 °C.
(c) Repeat steps (III)(1)(d)(ii) through (III)(5)(c) of this appendix.
(7) Temperature Cycling.
(a) Repeat steps (III)(1)(a) through (III)(1)(c)(iii) of this appendix for separate set of samples B, C, D and E which have not been subjected to prior environmental conditioning.
(b) Immediately after completing the measurements, subject the test sample to 10 cycles of temperature between −40 °C and + 60 °C. The test sample must be held at each temperature extreme for a minimum of 1
1/2 hours during each cycle of temperature. The air within the temperature cycling chamber must be circulated throughout the duration of the cycling.
(c) Repeat steps (III)(1)(d)(ii) through (III)(5)(c) of this appendix.
(IV) Control Sample—(1) Test Samples. A separate set of lengths for samples A, C, D, and E must have been maintained at 23 ±3 °C for at least 48 hours before the testing.
(2) Repeat steps (III)(2) through (III)(5)(c) of this appendix except use length A instead of length B.
(3) Surge Test.
(a) One length of sample F must be used to measure the breakdown between conductors while the other length of F must be used to measure core to shield breakdown.
(b) The samples must be capable of withstanding, without damage, a single surge voltage of 20 kilovolts peak between conductors, and 35 kilovolts peak between conductors and the shield as hereinafter described. The surge voltage must be developed from a capacitor discharge through a forming resistor connected in parallel with the dielectric of the test sample. The surge generator constants must be such as to produce a surge of 1.5 × 40 microseconds wave shape.
(c) The shape of the generated wave must be determined at a reduced voltage by connecting an oscilloscope across the forming resistor with the wire sample connected in parallel with the forming resistor. The capacitor bank is charged to the test voltage and then discharged through the forming resistor and test sample. The test sample will be considered to have passed the test if there is no distinct change in the wave shape obtained with the initial reduced voltage compared to that obtained after the application of the test voltage.
(V) The following suggested formats may be used in submitting the test results to RUS: