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Timestamp: 2020-02-28 13:13:01
Document Index: 429553192

Matched Legal Cases: ['art 1755', '§1755', '§1755', 'art 51', 'art 51', '§1755', '§1755', '§1755']

Title 7 → Subtitle B → Chapter XVII → Part 1755 → §1755.860
§1755.860 RUS specification for filled buried wires.
(a) Scope. (1) This section covers the requirements for filled buried wires intended for direct burial as a subscriber drop and/or distribution wire.
(ii) The insulated conductors are twisted into pairs (a star-quad configuration is permitted for the two pair wires) which are then stranded or oscillated to form a cylindrical core.
(iii) A moisture resistant filling compound is applied to the stranded conductors completely covering the insulated conductors and filling the interstices between the pairs.
American Wire Gauge (AWG) 22 24
Pairs 2 2
(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.
(b) Conductors and conductor insulation. (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.
Conductor—AWG
Minimum Elongation—Percent
(4)(i) The tensile strength of any section of a conductor containing a factory joint must not be less than 85 percent of the tensile strength of an adjacent section of the solid conductor of equal length without a joint.
(ii) Engineering Information: The sizes of wire used and their nominal diameters shall be as shown in the following table:
22 0.643 (0.0253)
24 0.511 (0.0201)
<0.5 (Initial Melt Index) 50 —
0.5-2.00 (Initial Melt Index) 25 —
≤5.0 (Initial Melt Index) — 110
Tensile Strength—Minimum
Megapascals (MPa) 16.5 21.0
(Pounds per Square Inch (psi)) (2,400) (3,000)
Minimum, Percent 300 300
Failures, Maximum 0/10 0/10
Maximum, mm (in.) 10 (0.375) 10 (0.375)
Minimum, Minutes 20 20
(11) Testing procedures. The procedures for testing the insulation samples for compliance with paragraph (b)(10) of this section must be as follows.
(i) Melt flow rate. The melt flow rate must be determined as described in ASTM D 1238-90b. Condition E must be used for polyethylene. Condition L must be used for crystalline propylene/ethylene copolymer. The melt flow test must be conducted prior to the filling operation.
(ii) Tensile strength and ultimate elongation. Samples of the insulation material, removed from the conductor, must be tested in accordance with ASTM D 4565-90a using the following conditions. The minimum length of unclamped specimen must be 50 mm (2.0 in.). The minimum speed of jaw separation must be 25 mm (1.0 in.) per minute per 25 mm (1.0 in.) of unclamped specimen. The temperature of specimens and surrounding shall be 23 ±1 °C.
Note: Quality assurance testing at a jaw separation speed of 500 mm/min (20 in./min) is permissible. Failures at this rate must be retested at the 50 mm/min (2 in./min) rate to determine section compliance.
(iii) Cold bend. Samples of the insulation material on the conductor must be tested in accordance with ASTM D 4565-90a at a temperature of −40 ±1 °C with a mandrel diameter equal to 3 times the outside diameter of the insulated conductor. There must be no cracks visible to normal or corrected-to-normal vision.
(iv) Shrinkback. Samples of insulation must be tested for four hours in accordance with ASTM D 4565-90a. The temperature for the type of material is listed as follows:
Polyethylene 115 ±1 °C
Crystalline propylene/ethylene Copolymer 130 ±1 °C
(v) Oxygen induction time. Samples of insulation, which have been conditioned in accordance with paragraph 17.3 of ASTM D 4565-90a, must be tested in accordance with the procedures of ASTM D 4565-90a using copper pans and a test temperature of 199 ±1 °C.
(c) Identification of pairs and twisting of pairs. (1) The insulation must be colored to identify:
(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).
1 White with blue stripe Blue
2 White with orange stripe Orange
(d) Forming of the wire core. (1) Twisted pairs or star-quad configuration must be assembled in such a way as to form a substantially cylindrical group.
(e) Filling compound. (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.
(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.
(f) Core wrap (optional). (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.
(g) Inner jacket. (1) An inner jacket must be applied over the core and/or core wrap.
(h) Flooding compound. (1) Sufficient flooding compound must be applied on all sheath interfaces so that voids and air spaces in these areas are minimized.
(i) Shield. (1) A shield must be applied either longitudinally or helically over the inner jacket.
Copper Alloy 220 (Bronze) Copper-Clad Stainless Steel
(0.1016 ±0.0076 mm) 0.1270 ±0.0127 mm
(0.0040 ±0.0003 in.) (0.0050 ±0.0005 in.)
Copper Alloy 220 (Bronze) Copper Alloy 664
0.1270 ±0.0127 mm 0.1397 ±0.0127 mm
(0.0050 ±0.0005 in.) (0.0055 ±0.0005 in.)
Minimum, MPa (psi) 379 (55,000)
Minimum, MPa (psi) 241 (35,000)
Minimum, percent in 50 mm (2 in.) 15
(ii) Copper alloy 220. The shielding material, prior to application to the wire, must be in the fully annealed condition and shall conform to the requirements of ASTM B 694-86 for C22000 commercial bronze.
(iii) Copper-clad stainless steel. In addition to meeting the requirements of paragraph (i)(4)(i) of this section, the shielding material, prior to application to the wire, must be in the fully annealed condition and must conform to the requirements of ASTM B 694-86, with a cladding ratio of 16/68/16 and must have a minimum electrical conductivity of 28 percent IACS when measured in accordance with ASTM B 193-87.
(iv) Copper alloy 664. In addition to meeting the requirements of paragraph (i)(4)(i) of this section, the shielding material, prior to application to the wire, must be annealed temper and must conform to the requirements of ASTM B 694-86 and must have a minimum electrical conductivity of 28 percent IACS when measured in accordance with ASTM B 193-87.
(v) Copper-clad alloy steel. In addition to meeting the requirements of paragraph (i)(4)(i) of this section, the shielding material, prior to application to the wire, must be in the fully annealed condition and the copper component must conform to the requirements of ASTM B 224-91 and the alloy steel component must conform to the requirements of ASTM A 505-87, with a cladding ratio of 16/68/16, and must have a minimum electrical conductivity of 28 percent IACS when measured in accordance with ASTM B 193-87.
(j) Outer jacket. (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.
Melt Flow Rate Percent increase from raw material Maximum 50 50
<0.41 (Initial Melt Index) 100 — —
0.41-2.00 (Initial Melt Index) 50 — —
Tensile Strength Minimum, MPa (psi) 12.0 (1,700) 12.0 (1,700) 16.5 (2,400)
Ultimate Elongation Percent, Minimum 400 400 300
Shrinkback Percent of Length, Maximum 5 5 5
Impact Failures, Maximum 2/10 2/10 2/10
(5) Testing procedures. The procedures for testing the jacket samples for compliance with paragraph (j)(4) of this section must be as follows:
(i) Melt flow rate. The melt flow rate must be as determined by ASTM D 1238-90b, Condition E. Jacketing material must be free from flooding and filling compound.
(ii) Tensile strength and ultimate elongation. Test in accordance with ASTM D 4565-90a, using a jaw separation speed of 500 mm/min (20 in./min) for low density material and 50 mm/min (2 in./min) for high and medium density materials.
(iii) Shrinkback. Test in accordance with the procedures specified in ASTM D 4565-90a using a test temperature of 100 ±1 °C for low density material and a test temperature of 115 ±1 °C for high and medium density materials.
(iv) Impact. The test must be performed in accordance with ASTM D 4565-90a using an impact force of 4 newton-meter (3 pound force-foot) at a temperature of −20 ±2 °C. The cylinder must strike the sample at the shield overlap. A crack or split in the jacket constitutes failure.
(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:
(k) Sheath slitting cord (optional). (1) Sheath slitting cords may be used in the wire structure at the option of the manufacturer.
(l) Identification marker and length marker. (1) Each length of wire must be permanently identified as to manufacturer and year of manufacture.
(m) Electrical requirements—(1) Mutual capacitance and conductance. (i) The average mutual capacitance (corrected for length) of all pairs in any reel must not exceed 52 ±4 nanofarad/ kilometer (nF/km) (83 ±7 nanofarad/mile (nF/mile)) when tested in accordance with ASTM D 4566-90 at a frequency of 1.0 ±0.1 kilohertz (kHz) and a temperature of 23 ±3 °C.
(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—(i) Pair-to-ground. The capacitance unbalance as measured on the individual pairs of the completed wire must not exceed 2625 pF/km (800 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.
(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 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.
Individual Pair Attenuation dB/km (decibel/mile (dB/mile))
22 6.8 (11.0) 5.0 (8.1)
24 8.7 (14.0) 6.6 (10.7)
(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:
(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.
22 57.1 (17.4)
24 90.2 (27.5)
(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.
(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.
(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.
(i) An original signature certification that the product fully complies with each requirement of this section;
(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.);
(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.
(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:
(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.
(q) Manufacturing irregularities. (1) Repairs to the inner jacket and shield are not permitted in wire supplied to the end user under this section.
(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.
Example: BFWY 3-24
Buried Filled Wire, Gopher Resistant Shield, 3 pair, 24 AWG
Appendix A to §1755.860—Qualification Test Methods
(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.
(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:
(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.
(d) Heat Conditioning. (i) Immediately after completing the initial measurements, condition the sample for 14 days at a temperature of 65 ±2 °C.
(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.
(A) Capacitance. The average mutual capacitance must be within 5 percent of its original value;
(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.
(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.
(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.
(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.
(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 11⁄2 hours during each cycle of temperature. The air within the temperature cycling chamber must be circulated throughout the duration of the cycling.
(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.
(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.
Average x̅ ____ ____ ____ ____
Overall Percent Difference in Average x̅ Capacitance:______________ Conductance: ______________
1 ___ ___ ___ ___ ___ ___
2 ___ ___ ___ ___ ___ ___
Average x̅ ___ ___ ___ ___ ___ ___
Overall Percent Difference in Average x̅ Capacitance:___________ Conductance: ___________ Attenuation:___________
Control _____ _____ _____ _____
Heat Age _____ _____ _____ _____
Humidity Exposure _____ _____ _____ _____
Temperature Cycling _____ _____ _____ _____
Control ________
Heat Age ________
Humidity Exposure ________
Temperature Cycling ________
Temperature Cycle ________
Conductor to Conductor ________
Shield to Conductors ________
Appendix B to §1755.860—Sheath Slitting Cord Qualification
(II) Sample Selection. All testing must be performed on two 1.2 meters (4 feet) lengths of wire 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.
(III) Test Procedure. (1) Using a suitable tool, expose enough of sheath slitting cord to permit grasping with needle nose pliers.
Appendix C to §1755.860—Thermal Reel Wrap Qualification
(II) Sample Selection. All testing must be performed on two 450 millimeter (18 inch) lengths of wire 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.
(III) Test Procedure. (1) Place the two samples on an insulating material such as wood, etc.
[58 FR 61004, Nov. 19, 1993, as amended at 60 FR 1711, Jan. 5, 1995; 69 FR 18803, Apr. 9, 2004]