[Code of Federal Regulations]
[Title 7, Volume 11]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 7CFR1755.870]
[Page 680-694]
TITLE 7--AGRICULTURE
CHAPTER XVII--RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE
PART 1755--TELECOMMUNICATIONS STANDARDS AND SPECIFICATIONS FOR MATERIALS, EQUIPMENT AND CONSTRUCTION--Table of Contents
Sec. 1755.870 RUS specification for terminating cables.
(a) Scope. (1) This section establishes the requirements for
terminating cables used to connect incoming outside plant cables to the
vertical side of the main distributing frame in a telephone central
office.
(i) The conductors are solid tinned copper, individually insulated
with extruded solid dual insulating compounds.
(ii) The insulated conductors are twisted into pairs which are then
stranded or oscillated to form a cylindrical core.
(iii) The cable structure is completed by the application of a core
wrap, a shield, and a polyvinyl chloride jacket.
(2) The number of pairs and gauge size of conductors which are used
within the RUS program are provided in the following table:
------------------------------------------------------------------------
American Wire Gauge (AWG) 22 24
------------------------------------------------------------------------
Number of Pairs........................................... 12 12
50 50
100 100
200 200
300 300
400 400
600 600
800 800
------------------------------------------------------------------------
Note: Cables larger in pair sizes from those shown in this table shall
meet all the requirements of this section.
(3) All cables sold to RUS borrowers for projects involving RUS loan
funds under this section must be accepted by RUS Technical 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.
(4) Materials, manufacturing techniques, or cable designs not
specifically addressed by this section may be allowed if accepted by
RUS. Justification for acceptance of modified materials, manufacturing
techniques, or cable designs shall be provided to substantiate product
utility and long term stability and endurance.
(5) The American National Standard 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 Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
Copies are available from Global Engineering Documents, 15 Inverness Way
East, Englewood, CO 80112, telephone number (303) 792-2181.
[[Page 681]]
(6) American Society for Testing and Materials Specifications (ASTM)
B 33-91, Standard Specification for Tinned Soft or Annealed Copper Wire
for Electrical Purposes; ASTM B 736-92a Standard Specification for
Aluminum, Aluminum Alloy and Aluminum-Clad Steel Cable Shielding Stock;
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 2287-81 (Reapproved
1988), Standard Specification for Nonrigid Vinyl Chloride Polymer and
Copolymer Molding and Extrusion Compounds; ASTM D 2436-85, Standard
Specification for Forced-Convection Laboratory Ovens for Electrical
Insulation; ASTM D 2633-82 (Reapproved 1989), Standard Methods of
Testing Thermoplastic Insulations and Jackets for Wire and Cable; 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; 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 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 ASTM, 1916 Race Street,
Philadelphia, Pennsylvania 19103-1187, telephone number (215) 299-5585.
(7) American National Standards Institute/National Fire Protection
Association (ANSI/NFPA), NFPA 70-1993 National Electrical Code
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. A copy of
the ANSI/NFPA standard is 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 NFPA, Batterymarch Park, Quincy, Massachusetts 02269,
telephone number 1 (800) 344-3555.
(8) Underwriters Laboratories Inc. (UL) 1666, Standard Test for
Flame Propagation Height of Electrical and Optical-Fiber Cables
Installed Vertically in Shafts, dated January 22, 1991, 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. A copy of the UL
standard is 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 UL Inc., 333
Pfingsten Road, Northbrook, Illinois 60062-2096, telephone number (708)
272-8800.
(b) Conductors and conductor insulation. (1) Each conductor shall be
a solid round wire of commercially pure annealed tin coated copper.
Conductors shall meet the requirements of the American Society for
Testing and Materials (ASTM) B 33-91 except that requirements for
Dimensions and Permissible Variations are waived.
(2) 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 shall be butted.
Splices made in insulated conductors need not be butted but may be
joined in a manner acceptable to RUS.
[[Page 682]]
(3) The tensile strength of any section of a conductor, containing a
factory joint, shall not be less than 85 percent of the tensile strength
of an adjacent section of the solid conductor of equal length without a
joint.
(4) Engineering Information: The sizes of wire used and their
nominal diameters shall be as shown in the following table:
------------------------------------------------------------------------
Nominal diameter
AWG -------------------------
Millimeters (Inches)
------------------------------------------------------------------------
22............................................ 0.643 (0.0253)
24............................................ 0.511 (0.0201)
------------------------------------------------------------------------
(5) Each conductor shall be insulated with a primary layer of
natural or white solid, insulating grade, high density polyethylene or
crystalline propylene/ethylene copolymer and an outer skin of colored,
solid, insulating grade, polyvinyl chloride (PVC) using one of the
insulating materials listed in paragraphs (b)(5)(i) through (iii) of
this section.
(i) The polyethylene raw material selected to meet the requirements
of this section shall be Type III, Class A, Category 4 or 5, Grade E9,
in accordance with ASTM D 1248-84 (1989).
(ii) The crystalline propylene/ethylene raw material selected to
meet the requirements of this section shall be Class PP 200B 40003 E11
in accordance with ASTM D 4101-82 (1988).
(iii) The PVC raw material selected to meet the requirements of this
section shall be either Type PVC-64751E3XO, Type PVC-76751E3XO, or Type
PVC-77751E3XO in accordance with ASTM D 2287-81 (1988).
(iv) Raw materials intended as conductor insulation furnished to
these requirements shall be free from dirt, metallic particles, and
other foreign matter.
(v) All insulating raw materials shall be accepted by RUS prior to
their use.
(6) All conductors in any single length of cable shall be insulated
with the same type of material.
(7) A permissible overall performance level of faults in conductor
insulation when using the test procedures in paragraph (b)(8) of this
section shall average not greater than one fault per 12,000 conductor
meters (40,000 conductor feet) for each gauge of conductor.
(8) The test used to determine compliance with paragraph (b)(7) of
this section shall be conducted as follows:
(i) Samples tested shall be taken from finished cables selected at
random from standard production cable. The samples tested shall contain
a minimum of 300 conductor meters (1,000 conductor feet) for cables
sizes less than 50 pairs and 1,500 conductor meters (5,000 conductor
feet) for cables sizes greater than or equal to 50 pairs. No further
sample need be taken from the same cable production run within 6,000
cable meters (20,000 cable feet) of the original test sample from that
run.
(ii) The cable sample shall have its jacket, shield, and core wrap
removed and its core shall be immersed in tap water for a minimum period
of 6 hours. In lieu of removing the jacket, shield, and core wrap from
the core, the entire cable may be tested. In this case, the core shall
be completely filled with tap water, under pressure; then the cable
assembly shall be immersed for a minimum period of 6 hours. With the
cable core still fully immersed, except for end connections, the
insulation resistance (IR) of all conductors to water shall be measured
using a direct current (dc) voltage of 100 volts to 550 volts.
(iii) An IR value of less than 500 megohms for any individual
insulated conductor tested at or corrected to a temperature of 23 deg.C
is considered a failure. If the cable sample is more than 7.5 meters (25
feet) long, all failing conductors shall be retested and reported in 7.5
meter (25 foot) segments.
(iv) The pair count, gauge, footage, and number of insulation faults
shall be recorded. This information shall be retained on a 6 month
running basis for review by RUS when requested.
(v) A fault rate, in a continuous length in any one reel, in excess
of one fault per 3,000 conductor meters (10,000 conductor feet) due to
manufacturing defects is cause for rejection. A minimum of 6,000
conductor meters (20,000 conductor feet) is required to develop a
noncompliance in a reel.
[[Page 683]]
(9) Repairs to the conductor insulation during manufacturing are
permissible. The method of repair shall be accepted by RUS prior to its
use. The repaired insulation shall be capable of meeting the relevant
electrical requirements of this section.
(10) All repaired sections of insulation shall be retested in the
same manner as originally tested for compliance with paragraph (b)(7) of
this section.
(11) The colored composite insulating material removed from or
tested on the conductor, from a finished cable, shall be capable of
meeting the following performance requirements:
------------------------------------------------------------------------
Composite
Property insulation
------------------------------------------------------------------------
Tensile Strength, Minimum Megapascals (MPa) (Pounds per 16.5 (2400)
square inch (psi))........................................
Ultimate Elongation Percent, Minimum....................... 125
Cold Bend Failures, Maximum................................ 0/10
Shrinkback, Maximum Millimeter (mm) (Inches (in.))......... 9.5 (3/8)
Adhesion, Maximum Newtons (N) (Pound-force (lbf)).......... 13.3 (3)
Compression Minimum, N (lbf)............................... 1780 (400)
------------------------------------------------------------------------
(12) Testing procedures. The procedures for testing the composite
insulation samples for compliance with paragraph (b)(11) of this section
shall be as follows:
(i) Tensile strength and ultimate elongation. Samples of the
insulation material, removed from the conductor, shall be tested in
accordance with ASTM D 2633-82(1989), except that the speed of jaw
separation shall be 50 millimeters/minute (50 mm/min) (2 inches/minute
(2 in./min)).
Note: Quality assurance testing at a jaw separation speed of 500 mm/
min (20 in./min) is permissible. Failures at this rate shall be retested
at the 50 mm/min (2 in./min) rate to determine specification compliance.
(ii) Cold bend. Samples of the insulation material on the conductor
shall be tested in accordance with ASTM D 4565-90a at a temperature of -
401 deg.C with a mandrel diameter of 6 mm (0.25 in.). There
shall be no cracks visible to normal or corrected-to-normal vision.
(iii) Shrinkback. Samples of insulation shall be tested for four
hours at a temperature of 1151 deg.C in accordance with
ASTM D 4565-90a.
(iv) Adhesion. Samples of insulation material on the conductor shall
be tested in accordance with ASTM D 4565-90a with a crosshead speed of
50 mm/min (2 in./min).
(v) Compression. Samples of the insulation material on the conductor
shall be tested in accordance with ASTM D 4565-90a with a crosshead
speed of 5 mm/min (0.2 in./min).
(13) Other methods of testing may be used if acceptable to RUS.
(c) Identification of pairs and twisting of pairs. (1) The PVC skin
shall be colored to identify:
(i) The tip and ring conductor of each pair; and
(ii) Each pair in the completed cable.
(2) The colors used to provide identification of the tip and ring
conductor of each pair shall be as shown in the following table:
------------------------------------------------------------------------
Color
Pair No. -----------------------------------
Tip Ring
------------------------------------------------------------------------
1.................................. White Blue
2.................................. White Orange
3.................................. White Green
4.................................. White Brown
5.................................. White Slate
6.................................. Red Blue
7.................................. Red Orange
8.................................. Red Green
9.................................. Red Brown
10.................................. Red Slate
11.................................. Black Blue
12.................................. Black Orange
13.................................. Black Green
14.................................. Black Brown
15.................................. Black Slate
16.................................. Yellow Blue
17.................................. Yellow Orange
18.................................. Yellow Green
19.................................. Yellow Brown
20.................................. Yellow Slate
21.................................. Violet Blue
22.................................. Violet Orange
23.................................. Violet Green
24.................................. Violet Brown
25.................................. Violet Slate
------------------------------------------------------------------------
(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 shall 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.
[[Page 684]]
The method of marking shall 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 shall be twisted into pairs.
(7) In order to provide sufficiently high crosstalk isolation, the
pair twists shall be designed to enable the cable to meet the
capacitance unbalance and the crosstalk loss requirements of paragraphs
(h)(2), (h)(3), and (h)(4) of this section.
(8) The average length of pair twists in any pair in the finished
cable, when measured on any 3 meter (m) (10 foot (ft)) length, shall not
exceed 152 mm (6 in.).
(d) Forming of the cable core. (1) Twisted pairs shall be assembled
in such a way as to form a substantially cylindrical group.
(2) When desired for lay-up reasons, the basic group may be divided
into two or more subgroups called units.
(3) Each group, or unit in a particular group, shall be enclosed in
bindings of the colors indicated for its particular pair count. The pair
count, indicated by the color of insulation, shall be consecutive as
indicated in paragraph (d)(5) of this section through units in a group.
(4) Threads or tapes used as binders shall be nonhygroscopic and
nonwicking. The threads shall consists of a suitable number of ends of
each color arranged as color bands. When tapes are used as binders, they
shall be colored. Binders shall be applied with a lay of not more than
100 mm (4 in.). The colored binders shall be readily recognizable as the
basic intended color and shall be distinguishable from all other colors.
(5) The colors of the bindings and their significance with respect
to pair count shall be as shown in the following table:
------------------------------------------------------------------------
Group No. Color of bindings Group pair count
------------------------------------------------------------------------
1..................... White-Blue.............. 1-25
2..................... White-Orange............ 26-50
3..................... White-Green............. 51-75
4..................... White-Brown............. 76-100
5..................... White-Slate............. 101-125
6..................... Red-Blue................ 126-150
7..................... Red-Orange.............. 151-175
8..................... Red-Green............... 176-200
9..................... Red-Brown............... 201-225
10.................... Red-Slate............... 226-250
11.................... Black-Blue.............. 251-275
12.................... Black-Orange............ 276-300
13.................... Black-Green............. 301-325
14.................... Black-Brown............. 326-350
15.................... Black-Slate............. 351-375
16.................... Yellow-Blue............. 376-400
17.................... Yellow-Orange........... 401-425
18.................... Yellow-Green............ 426-450
19.................... Yellow-Brown............ 451-475
20.................... Yellow-Slate............ 476-500
21.................... Violet-Blue............. 501-525
22.................... Violet-Orange........... 526-550
23.................... Violet-Green............ 551-575
24.................... Violet-Brown............ 576-600
------------------------------------------------------------------------
(6) The use of the white unit binder in cables of 100 pair or less
is optional.
(7) When desired for manufacturing reasons, two or more 25 pair
groups may be bound together with nonhygroscopic and nonwicking threads
or tapes into super-units. The group binders and the super-unit binders
shall be colored such that the combination of the two binders shall
positively identify each 25 pair group from every other 25 pair group in
the cable.
(8) Super-unit binders shall be of the colors shown in the following
table:
Super-Unit Binder Colors
------------------------------------------------------------------------
Pair No. Binder color
------------------------------------------------------------------------
1-600..................................... White
601-1200.................................. Red
------------------------------------------------------------------------
(e) Core wrap.(1) The core shall be completely covered with a layer
of nonhygroscopic and nonwicking dielectric material. The core wrap
shall be applied with an overlap.
(2) The core wrap shall provide a sufficient heat barrier to prevent
visible evidence of conductor insulation deformation or adhesion between
conductors, caused by adverse heat transfer during the jacketing
operation.
(3) Engineering Information: If required for manufacturing reasons,
white or uncolored binders of nonhygroscopic and nonwicking material may
be applied over the core and/or core wrap.
(f) Shield. (1) An aluminum shield, plastic coated on one side,
shall be applied longitudinally over the core wrap.
[[Page 685]]
(2) The shield may be applied over the core wrap with or without
corrugations (smooth) and shall be bonded to the outer jacket.
(3) The shield overlap shall be a minimum of 3 mm (0.125 in.) for
cables with core diameters of 15 mm (0.625 in.) or less and a minimum of
6 mm (0.25 in.) for cables with core diameters greater than 15 mm (0.625
in.). The core diameter is defined as the diameter under the core wrap
and binding.
(4) General requirements for application of the shielding material
shall be as follows:
(i) Successive lengths of shielding tapes may be joined during the
manufacturing process by means of cold weld, electric weld, soldering
with a nonacid flux, or other acceptable means;
(ii) The metal shield with the plastic coating shall have the
coating removed prior to joining the metal ends together. After joining,
the plastic coating shall be restored without voids using good
manufacturing techniques;
(iii) The shields of each length of cable shall be tested for
continuity. A one meter (3 ft) section of shield containing a factory
joint shall exhibit not more than 110 percent of the resistance of a
shield of equal length without a joint;
(iv) The breaking strength of any section of a shield tape
containing a factory joint shall not be less than 80 percent of the
breaking strength of an adjacent section of the shield of equal length
without a joint;
(v) The reduction in thickness of the shielding material due to the
corrugating or application process shall be kept to a minimum and shall
not exceed 10 percent at any spot; and
(vi) The shielding material shall be applied in such a manner as to
enable the cable to pass the bend test as specified in paragraph (i)(1)
of this section.
(5) The dimensions of the uncoated aluminum tape shall be
0.20300.0254 mm (0.00800.0010 in.).
(6) The aluminum tape shall conform to either Alloy AA-1100-0, AA-
1145-0, or AA-1235-0 as covered in the latest edition of Aluminum
Standards and Data, issued by the Aluminum Association, except that
requirements for tensile strength are waived.
(7) The single-sided plastic coated aluminum shield shall conform to
the requirements of ASTM B 736-92a, Type I Coating, Class 1 or 2, or
Type II Coating, Class 1. The minimum thickness of the Type I Coating
shall be 0.038 mm (0.0015 in.). The minimum thickness of the Type II
Coating shall be 0.008 mm (0.0003 in.).
(8) The plastic coated aluminum shield shall be tested for
resistance to water migration by immersing a one meter (3 ft) length of
tape under a one meter (3 ft) head of water containing a soluble dye
plus 0.25 percent (%) wetting agent.
(i) After a minimum of 5 minutes, no dye shall appear between the
interface of the shield tape and the plastic coating.
(ii) The actual test method shall be acceptable to RUS.
(9) The bond between the plastic coated shield and the jacket shall
conform to the following requirements:
(i) Prepare test strips approximately 200 mm (8 in.) in length. Slit
the jacket and shield longitudinally to produce 4 strips evenly spaced
and centered in 4 quadrants on the jacket circumference. One of the
strips shall be centered over the overlapped edge of the shielding tape.
The strips shall be 13 mm (0.5 in.) wide. For cable diameters less than
19 mm (0.75 in.) make two strips evenly spaced.
(ii) Separate the shield and jacket for a sufficient distance to
allow the shield and jacket to be fitted in the upper and lower jaws of
a tensile machine. Record the maximum force required to separate the
shield and jacket to the nearest newton (pound-force). Repeat this
action for each test strip.
(iii) The force required to separate the jacket from the shield
shall not be less than 9 N (2 lbf) for any individual strip when tested
in accordance with paragraph (f)(9)(ii) of this section. The average
force for all strips of any cable shall not be less than 18 N (4 lbf).
(g) Cable jacket and extraneous material. (1) The jacket shall
provide the cable with a tough, flexible, protective covering which can
withstand stresses reasonably expected in normal installation and
service.
[[Page 686]]
(2) The jacket shall be free from holes, splits, blisters, or other
imperfections and shall be as smooth and concentric as is consistent
with the best commercial practice.
(3) The raw material used for the cable jacket shall be one of the
following four types:
(i) Type PVC-55554EOXO in accordance with ASTM D 2287-81(1988);
(ii) Type PVC-65554EOXO in accordance with ASTM D 2287-81(1988);
(iii) Type PVC-55556EOXO in accordance with ASTM D 2287-81(1988); or
(iv) Type PVC-66554EOXO in accordance with ASTM D 2287-81(1988).
(4) The jacketing material removed from or tested on the cable shall
be capable of meeting the following performance requirements:
------------------------------------------------------------------------
Jacket
Property performance
------------------------------------------------------------------------
Tensile Strength-Unaged Minimum, MPa (psi)................ 13.8 (2000)
Ultimate Elongation-Unaged Minimum, Percent (%)........... 200
Tensile Strength-Aged Minimum, % of original value........ 80
Ultimate Elongation-Aged Minimum, % of original value..... 50
Impact Failures, Maximum.................................. 2/10
------------------------------------------------------------------------
(5) Testing procedures. The procedures for testing the jacket
samples for compliance with paragraph (g)(4) of this section shall be as
follows:
(i) Tensile strength and ultimate elongation-unaged. The test shall
be performed in accordance with ASTM D 2633-82(1989), using a jaw
separation speed of 50 mm/min (2 in./min).
Note: Quality assurance testing at a jaw separation speed of 500 mm/
min (20 in./min) is permissible. Failures at this rate shall be retested
at the 50 mm/min (2 in./min) rate to determine specification compliance.
(ii) Tensile strength and ultimate elongation-aged. The test shall
be performed in accordance with paragraph (g)(5)(i) of this section
after being aged for 7 days at a temperature of 1001 deg.C
in a circulating air oven conforming to ASTM D 2436-85.
(iii) Impact. The test shall 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 -101 deg.C. The cylinder shall strike the
sample at the shield overlap. A crack or split in the jacket constitutes
failure.
(6) Jacket thickness. The nominal jacket thickness shall be as
specified in the following table. The test method used shall be either
the End Sample Method (paragraph (g)(6)(i) of this section) or the
Continuous Uniformity Thickness Gauge Method (paragraph (g)(6)(ii) of
this section):
------------------------------------------------------------------------
Nominal jacket thickness mm
No. of pairs (in.)
------------------------------------------------------------------------
25 or less............................... 1.4 (0.055)
50....................................... 1.5 (0.060)
100...................................... 1.7 (0.065)
200...................................... 1.9 (0.075)
300...................................... 2.2 (0.085)
400...................................... 2.4 (0.095)
600...................................... 2.9 (0.115)
800 and over............................. 3.3 (0.130)
------------------------------------------------------------------------
(i) End sample method. The jacket shall be capable of meeting the
following requirements:
Minimum Average Thickness--90% of nominal thickness
Minimum Thickness--70% of nominal thickness
(ii) Continuous uniformity thickness gauge method. (A) The jacket
shall be capable of meeting the following requirements:
Minimum Average Thickness--90% of nominal thickness
Minimum (Min.) Thickness--70 % of nominal thickness
Maximum (Max.) Eccentricity--55%
Eccentricity=Max. Thickness--Min. Thickness (Average Thickness)x100
(B) Maximum and minimum thickness values. The maximum and minimum
thickness values shall be based on the average of each axial section.
(7) The color of the jacket shall be either black or dark grey in
conformance with the Munsell Color System specified in ASTM D 1535-89.
(8) There shall be no water or other contaminants in the finished
cable which would have a detrimental effect on its performance or its
useful life.
(h) Electrical requirements--(1) Mutual capacitance and conductance.
(i) The average mutual capacitance (corrected for length) of all pairs
in any reel shall not exceed the following when tested in accordance
with ASTM D 4566-90 at a frequency of 1.00.1 kilohertz (kHz)
and a temperature of 233 deg.C:
[[Page 687]]
------------------------------------------------------------------------
Mutual capacitance
-------------------------
Number of cable pairs Nanofarad/ (Nanofarad/
kilometer mile)
------------------------------------------------------------------------
12............................................ 520.1 kHz and a temperature of 233
deg.C.
(2) Pair-to-pair capacitance unbalance. The capacitance unbalance as
measured on the completed cable shall not exceed 45.3 picofarad/
kilometer (pF/km) (25 picofarad/1000 ft (pF/1000 ft)) rms when tested in
accordance with ASTM D 4566-90 at a frequency of 1.00.1 kHz
and a temperature of 233 deg.C.
(3) Pair-to-ground capacitance unbalance. (i) The average
capacitance unbalance as measured on the completed cable shall not
exceed 574 pF/km (175 pF/1000 ft) when tested in accordance with ASTM D
4566-90 at a frequency of 10.1 kHz and a temperature of
233 deg.C.
(ii) When measuring pair-to-ground capacitance unbalance all pairs
except the pair under test are grounded to the shield except when
measuring cable containing super-units in which case all other pairs in
the same super-unit shall be grounded to the shield.
(iii) Pair-to-ground capacitance unbalance may vary directly with
the length of the cable.
(4) Crosstalk loss. (i) The rms output-to-output far-end crosstalk
loss (FEXT) measured on the completed cable in accordance with ASTM D
4566-90 at a test frequency of 150 kHz shall not be less than 68
decibel/kilometer (dB/km) (73 decibel/1000 ft (dB/1000 ft)). The rms
calculation shall be based on the combined total of all adjacent and
alternate pair combinations within the same layer and center to first
layer pair combinations.
(ii) The FEXT crosstalk loss between any pair combination of a cable
shall not be less than 58 dB/km (63 dB/1000 ft) at a frequency of 150
kHz. 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:
[GRAPHIC] [TIFF OMITTED] TR14JN94.000
(iii) The near-end crosstalk loss (NEXT) as measured within and
between units of a completed cable in accordance with ASTM D 4566-90 at
a frequency of 772 kHz shall not be less than the following mean minus
sigma (M-S) crosstalk requirement for any unit within the cable:
------------------------------------------------------------------------
M-S
Unit size decibel
(dB)
------------------------------------------------------------------------
Within Unit:
12 and 13 pairs............................................. 56
18 and 25 pairs............................................. 60
Between Unit:
Adjacent 13 pairs........................................... 65
Adjacent 25 pairs........................................... 66
Nonadjacent (all)........................................... 81
------------------------------------------------------------------------
Where M-S is the Mean near-end coupling loss based on the combined total
of all pair combinations, less one Standard Deviation, Sigma, of the
mean value.
(5) Insulation resistance. Each insulated conductor in each length
of completed cable, when measured with all other insulated conductors
and the shield grounded, shall have an insulation resistance of not less
than 152 megohm-kilometer (500 megohm-mile) at 201 deg.C.
The measurement shall be made in accordance with the procedures of ASTM
D 4566-90.
(6) High voltage test. (i) In each length of completed cable, the
dielectric strength of the insulation between conductors shall be tested
in accordance
[[Page 688]]
with ASTM D 4566-90 and shall withstand, for 3 seconds, a direct current
(dc) potential whose value is not less than:
(A) 3.6 kilovolts for 22-gauge conductors; or
(B) 3.0 kilovolts for 24-gauge conductors.
(ii) In each length of completed cable, the dielectric strength
between the shield and all conductors in the core shall be tested in
accordance with ASTM D 4566-90 and shall withstand, for 3 seconds, a dc
potential whose value is not less than 10 kilovolts.
(7) Conductor resistance. The dc resistance of any conductor shall
be measured in the completed cable in accordance with ASTM D 4566-90 and
shall not exceed the following values when measured at or corrected to a
temperature of 201 deg.C:
------------------------------------------------------------------------
Maximum resistance
-------------------------
AWG ohms/ (ohms/1000
kilometer ft)
------------------------------------------------------------------------
22............................................ 60.7 (18.5)
24............................................ 95.1 (29.0)
------------------------------------------------------------------------
(8) Resistance unbalance. (i) The difference in dc resistance
between the two conductors of a pair in the completed cable shall not
exceed the values listed in this paragraph when measured in accordance
with the procedures of ASTM D 4566-90:
------------------------------------------------------------------------
Resistance Maximum for
unbalance any reel
-------------------------
AWG Individual
Average pair
percent percent
------------------------------------------------------------------------
22............................................ 1.5 4.0
24............................................ 1.5 5.0
------------------------------------------------------------------------
(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.
(9) Electrical variations. (i) Pairs in each length of cable having
either a ground, cross, short, or open circuit condition shall not be
permitted.
(ii) The maximum number of pairs in a cable which may vary as
specified in paragraph (h)(9)(iii) of this section from the electrical
parameters given in this section are listed in this paragraph. These
pairs may be excluded from the arithmetic calculation:
------------------------------------------------------------------------
Maximum No.
of pairs
with
Nominal pair count allowable
electrical
variation
------------------------------------------------------------------------
12-100..................................................... 1
101-300.................................................... 2
301-400.................................................... 3
401-600.................................................... 4
601 and above.............................................. 6
------------------------------------------------------------------------
(iii) Parameter variations--(A) Capacitance unbalance-to-ground. If
the cable fails either the maximum individual pair or average
capacitance unbalance-to-ground requirement and all individual pairs are
3280 pF/km (1000 pF/1000 ft) or less the number of pairs specified in
paragraph (h)(9)(ii) of this section may be eliminated from the average
and maximum individual calculations.
(B) Resistance unbalance. Individual pair of not more than 7 percent
for all gauges.
(C) Far end crosstalk. Individual pair combination of not less than
52 dB/km (57 dB/1000 ft).
Note: RUS recognizes that in large pair count cables (600 pair and
above) a cross, short, or open circuit condition occasionally may
develop in a pair which does not affect the performance of the other
cable pairs. In these circumstances rejection of the entire cable may be
economically unsound or repairs may be impractical. In such
circumstances the manufacturer may desire to negotiate with the customer
for acceptance of the cable. No more than 0.5 percent of the pairs may
be involved.
(i) Mechanical requirements--(1) Cable cold bend test. The completed
cable shall be capable of meeting the requirements of ASTM D 4565-90a
after conditioning at -20 2 deg.C except the mandrel
diameters shall be as specified below:
------------------------------------------------------------------------
Cable outside diameter Mandrel diameter
------------------------------------------------------------------------
<40 mm (1.5 in.)............................ 15x
40 mm (1.5 in.).................. 20x
------------------------------------------------------------------------
(2) Cable flame test. The completed cable shall be capable of
meeting a maximum flame height of 3.7 m (12.0 ft) when tested in
accordance with Underwriters Laboratories (UL) 1666 dated January 22,
1991.
[[Page 689]]
(3) Cable listing. All cables manufactured to the specification of
this section at a minimum shall be listed as Communication Riser Cable
(Type CMR) in accordance with Sections 800-50 and 800-51(b) of the 1993
National Electrical Code.
(j) Sheath slitting cord (optional). (1) Sheath slitting cords may
be used in the cable structure at the option of the manufacturer.
(2) When a sheath slitting cord is used it shall be nonhygroscopic
and nonwicking, continuous throughout a length of cable, and of
sufficient strength to open the sheath without breaking the cord.
(3) Sheath slitting cords shall be capable of consistently slitting
the jacket 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.
(k) Identification marker and length marker. (1) Each length of
cable shall be permanently identified as to manufacturer and year of
manufacture.
(2) The number of conductor pairs and their gauge size shall be
marked on the jacket.
(3) The marking shall 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 cable shall 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 shall be such that for any single
length of cable, continuous sequential numbering shall be employed.
(7) The numbers shall be dimensioned and spaced to produce good
legibility and shall 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 shall 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 shall 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 shall be
considered in acceptance of the method.
(9) The accuracy of the length marking shall be such that the actual
length of any cable 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 for a black colored jacket
shall be either white or silver. The color of the initial marking for a
dark grey colored jacket shall be either red or black. If the initial
marking of the black colored jacket 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 cable and re-mark with yellow. If the
initial marking of the dark grey colored jacket fails to meet the
requirements of the preceding paragraphs, it will be permissible to
either remove the defective marking and re-mark with the red or black
color or leave the defective marking on the cable and re-mark with
yellow. No further re-marking is permitted. Any re-marking shall be on a
different portion of the cable 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 cable which contains more than one set of
sequential markings shall be labeled to indicate the color and sequence
of marking to be used. The labeling shall be applied to the reel and
also to the cable.
(l) Preconnectorized cable (optional). (1) At the option of the
manufacturer and upon request by the purchaser, cables 100 pairs and
larger may be factory terminated in 25 pair splicing modules.
(2) The splicing modules shall meet the requirements of RUS Bulletin
345-54, PE-52, RUS Specification for Telephone Cable Splicing Connectors
(Incorporated by Reference at Sec. 1755.97), and be accepted by RUS
prior to their use.
[[Page 690]]
(m) Acceptance testing and extent of testing. (1) The tests
described in appendix A of this section are intended for acceptance of
cable 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 cable products
having long life and stability.
(2) For initial acceptance, the manufacturer shall submit:
(i) An original signature certification that the product fully
complies with each section of the specification;
(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 shall 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 shall 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 cable. (i) The shield of each
length of cable shall be tested for continuity using the procedures of
ASTM D 4566-90.
(ii) Dielectric strength between all conductors and the shield shall
be tested to determine freedom from grounds in accordance with paragraph
(h)(6)(ii) of this section.
(iii) Each conductor in the completed cable shall be tested for
continuity using the procedures of ASTM D 4566-90.
(iv) Dielectric strength between conductors shall be tested to
ensure freedom from shorts and crosses in accordance with paragraph
(h)(6)(i) of this section.
(v) Each conductor in the completed preconnectorized cable shall be
tested for continuity.
(vi) Each length of completed preconnectorized cable shall be tested
for split pairs.
(vii) The average mutual capacitance shall be measured on all
cables. If the average mutual capacitance for the first 100 pairs tested
from randomly selected groups is between 50 and 53 nF/km (80 to 85 nF/
mile), the remainder of the pairs need not to be tested on the 100
percent basis. (See paragraph (h)(1) of this section).
(6) Capability tests. Tests on a quality assurance basis shall 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) Bonding properties of coated or laminated shielding materials;
(iii) Sequential marking and lettering;
(iv) Capacitance unbalance and crosstalk;
(v) Insulation resistance;
(vi) Conductor resistance and resistance unbalance;
(vii) Cable cold bend and cable flame tests; and
(viii) Mutual conductance.
(n) Summary of records of electrical and physical tests. (1) Each
manufacturer shall maintain a suitable summary of records for a period
of at least 3 years for all electrical and physical tests required on
completed cable by this section as set forth in paragraphs (m)(5) and
(m)(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.
[[Page 691]]
(2) Measurements and computed values shall be rounded off to the
number of places of figures specified for the requirement according to
ASTM E 29-90.
(o) Manufacturing irregularities. (1) Repairs to the shield are not
permitted in cable supplied to the end user under this section.
(2) No repairs or defects in the jacket are allowed.
(p) Preparation for shipment. (1) The cable shall be shipped on
reels unless otherwise specified or agreed to by the purchaser. The
diameter of the drum shall be large enough to prevent damage to the
cable from reeling or unreeling. The reels shall be substantial and so
constructed as to prevent damage to the cable during shipment and
handling.
(2) A waterproof corrugated board or other means of protection
acceptable to RUS shall be applied to the reel and shall be suitably
secured in place to prevent damage to the cable during storage and
shipment.
(3) The outer end of the cable shall be securely fastened to the
reel head so as to prevent the cable from becoming loose in transit. The
inner end of the cable shall 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 cable jacket
shall not be used. The method of fastening the cable ends shall be
accepted by RUS prior to it being used.
(4) Each length of cable shall be wound on a separate reel unless
otherwise specified or agreed to by the purchaser.
(5) The arbor hole shall admit a spindle 63 mm (2.5 in.) in diameter
without binding. Steel arbor hole liners may be used but shall be
acceptable to RUS prior to their use.
(6) Each reel shall be plainly marked to indicate the direction in
which it should be rolled to prevent loosening of the cable on the reel.
(7) Each reel shall 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 cable, reel number and the RUS cable designation:
Cable Designation
CT
Cable Construction
Pair Count
Conductor Gauge
A = Coated Aluminum Shield
P = Preconnectorized Cable
Example: CTAP 100-22
Terminating Cable, Coated Aluminum Shield, Preconnectorized, 100 pairs,
22 AWG.
(8) When preconnectorized cable is shipped, the splicing modules
shall be protected to prevent damage during shipment and handling. The
protection method shall be acceptable to RUS prior to its use.
(The information collection and recordkeeping requirements of this
section have been approved by the Office of Management and Budget (OMB)
under control number 0572-0059)
Appendix A to Sec. 1755.870--Qualification Test Methods
(I) The test procedures described in this appendix are for
qualification of initial designs and major modifications of accepted
designs. Included in paragraph (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 shall be
performed on lengths removed sequentially from the same 25 pair, 22
gauge jacketed cable. This cable shall not have been exposed to
temperatures in excess of 38 deg.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 12 0.2 meters (40 0.5
feet) long. Prepare the test sample by removing the jacket, shield, and
core wrap 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 sample with a diameter of 15 to 20 times its sheath diameter.
Two lengths are required.
(b) Length B shall be 300 millimeters (1 foot) long. Three lengths
are required.
(c) Length C shall be 3 meters (10 feet) long and shall be
maintained at 23 3 deg.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 deg.C.
(III) Environmental Tests--(1) Heat Aging Test--(a) Test Samples.
Place one sample each of lengths A and B in an oven or environmental
chamber. The ends of sample A shall
[[Page 692]]
exit from the chamber or oven for electrical tests. Securely seal the
oven exit holes.
(b) Sequence of Tests. Sample B referenced in paragraph (III)(1)(a)
of this appendix shall be subjected to the insulation compression test
outlined in paragraph (III)(2) of this appendix.
(c) Initial Measurements. (i) For sample A, measure the open circuit
capacitance and conductance for each odd pair at 1, 150, and 772
kilohertz after conditioning the sample at the data reference
temperature for 24 hours. Calculate the average and standard deviation
for the data of the 13 pairs on a per kilometer (per mile) basis.
(ii) Record on suggested formats in paragraph (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 deg.C.
(ii) At the end of this period. Measure and calculate the parameters
given in paragraph (III)(1)(c) of this appendix. Record on suggested
formats in paragraph (V) of this appendix or on other easily readable
formats.
(e) Overall Electrical Deviation. (i) Calculate the percent change
in all average parameters between the final parameters after
conditioning with the initial parameters in paragraph (III)(1)(c) of
this appendix.
(ii) The stability of the electrical parameters after completion of
this test shall be within the following prescribed limits:
(A) Capacitance. The average mutual capacitance shall be within 10
percent of its original value;
(B) The change in average mutual capacitance shall be less than 10
percent over the frequency range of 1 to 150 kilohertz; and
(C) Conductance. The average mutual conductance shall not exceed 3.7
micromhos/kilometer (6 micromhos/mile) at a frequency of 1 kilohertz.
(2) Insulation Compression Test--(a) Test Sample B. Remove jacket,
shield, and core wrap being careful not to damage the conductor
insulation. Remove one pair from the core and carefully separate 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 in paragraph (V) of this appendix or on other
easily readable formats.
(3) Temperature Cycling. (a) Repeat paragraphs (III)(1)(a) through
(III)(1)(c)(ii) of this appendix for a separate set of samples A and B
which have not been subjected to prior environmental conditioning.
(b) Immediately after completing the measurements, subject the test
samples to 10 cycles of temperature between -40 deg.C and +60 deg.C.
The test samples shall be held at each temperature extreme for a minimum
of 1.5 hours during each cycle of temperature. The air within the
temperature cycling chamber shall be circulated throughout the duration
of the cycling.
(c) Repeat paragraphs (III)(1)(d)(ii) through (III)(2)(b) of this
appendix.
(IV) Control Sample--(1) Test Samples. One length of sample B shall
have been maintained at 23 3 deg.C for at least 48 hours
before the testing.
(2) Repeat paragraphs (III)(2) through (III)(2)(b) of this appendix.
(3) Surge Test. (a) One length of sample C shall be used to measure
the breakdown between conductors while the other length of C shall be
used to measure core to shield breakdown.
(b) The samples shall 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 shall be developed from a capacitor
discharge through a forming resistor connected in parallel with the
dielectric of the test sample. The surge generator constants shall be
such as to produce a surge of 1.5 x 40 microseconds wave shape.
(c) The shape of the generated wave shall be determined at a reduced
voltage by connecting an oscilloscope across the forming resistor with
the cable 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 shall 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:
[[Page 693]]
Environmental Conditioning ------------------
Frequency 1 Kilohertz
----------------------------------------------------------------------------------------------------------------
Capacitance nF/km (nF/ Conductance micromhos/km
mile) (micromhos/mile)
Pair No. ---------------------------------------------------
Initial Final Initial Final
----------------------------------------------------------------------------------------------------------------
1.......................................................... ........... ........... ........... ...........
3.......................................................... ........... ........... ........... ...........
5.......................................................... ........... ........... ........... ...........
7.......................................................... ........... ........... ........... ...........
9.......................................................... ........... ........... ........... ...........
11.......................................................... ........... ........... ........... ...........
13.......................................................... ........... ........... ........... ...........
15.......................................................... ........... ........... ........... ...........
17.......................................................... ........... ........... ........... ...........
19.......................................................... ........... ........... ........... ...........
21.......................................................... ........... ........... ........... ...........
23.......................................................... ........... ........... ........... ...........
25.......................................................... ........... ........... ........... ...........
Average x................................................... ........... ........... ........... ...........
Overall Percent Difference in
Average x............................................... ........... ........... ........... ...........
----------------------------------------------------------------------------------------------------------------
Environmental Conditioning --------------------
Frequency 150 Kilohertz
----------------------------------------------------------------------------------------------------------------
Capacitance nF/km (nF/ Conductance micromhos/km
mile) (micromhos/mile)
Pair No. ---------------------------------------------------
Initial Final Initial Final
----------------------------------------------------------------------------------------------------------------
1.......................................................... ........... ........... ........... ...........
3.......................................................... ........... ........... ........... ...........
5.......................................................... ........... ........... ........... ...........
7.......................................................... ........... ........... ........... ...........
9.......................................................... ........... ........... ........... ...........
11.......................................................... ........... ........... ........... ...........
13.......................................................... ........... ........... ........... ...........
15.......................................................... ........... ........... ........... ...........
17.......................................................... ........... ........... ........... ...........
19.......................................................... ........... ........... ........... ...........
21.......................................................... ........... ........... ........... ...........
23.......................................................... ........... ........... ........... ...........
25.......................................................... ........... ........... ........... ...........
Average x................................................... ........... ........... ........... ...........
Overall Percent Difference in Average x................. ........... ........... ........... ...........
----------------------------------------------------------------------------------------------------------------
Environmental Conditioning --------------------
Frequency 772 Kilohertz
----------------------------------------------------------------------------------------------------------------
Capacitance nF/km (nF/ Conductance micromhos/km
mile) (micromhos/mile)
Pair No. ---------------------------------------------------
Initial Final Initial Final
----------------------------------------------------------------------------------------------------------------
1.......................................................... ........... ........... ........... ...........
3.......................................................... ........... ........... ........... ...........
5.......................................................... ........... ........... ........... ...........
7.......................................................... ........... ........... ........... ...........
9.......................................................... ........... ........... ........... ...........
11.......................................................... ........... ........... ........... ...........
13.......................................................... ........... ........... ........... ...........
15.......................................................... ........... ........... ........... ...........
17.......................................................... ........... ........... ........... ...........
19.......................................................... ........... ........... ........... ...........
21.......................................................... ........... ........... ........... ...........
23.......................................................... ........... ........... ........... ...........
25.......................................................... ........... ........... ........... ...........
Average x................................................... ........... ........... ........... ...........
Overall Percent Difference in...........................
Average x............................................... ........... ........... ........... ...........
----------------------------------------------------------------------------------------------------------------
[[Page 694]]
------------------------------------------------------------------------
Failures
------------------------------------------------------------------------
Insulation Compression:
Control..................................................... ........
Heat Age.................................................... ........
Temperature Cycling......................................... ........
Surge Test (kilovolts):
Conductor-to-Conductor...................................... ........
Shield-to-Conductors........................................ ........
------------------------------------------------------------------------
Appendix B to Sec. 1755.870--Sheath Slitting Cord Qualification
(I) This test procedure described in this appendix is for
qualification of initial and subsequent changes in sheath slitting
cords.
(II) Sample selection. All testing shall be performed on two 1.2 m
(4 ft) lengths of cable removed sequentially from the same 25 pair, 22
gauge jacketed cable. This cable shall not have been exposed to
temperatures in excess of 38 deg.C since its initial cool down after
sheathing.
(III) Test procedure. (1) Using a suitable tool, expose enough of
the sheath slitting cord to permit grasping with needle nose pliers.
(2) The prepared test specimens shall be maintained at a temperature
of 23 1 deg.C for at least 4 hours immediately prior to and
during the test.
(3) Wrap the sheath slitting cord around the plier jaws to ensure a
good grip.
(4) Grasp and hold the cable in a convenient position while gently
and firmly pulling the sheath slitting cord longitudinally in the
direction away from the cable end. The angle of pull may vary to any
convenient and functional degree. A small starting notch is permissible.
(5) The sheath slitting cord is considered acceptable if the cord
can slit the jacket and/or shield for a continuous length of 0.6 m (2
ft) without breaking the cord.
[59 FR 30507, June 14, 1994; 59 FR 34899, July 7, 1994, as amended at 60
FR 1711, Jan. 5, 1995]