ASTM D4566-20

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4566 − 20
Standard Test Methods for
Electrical Performance Properties of Insulations and
Jackets for Telecommunications Wire and Cable
This standard is issued under the fixed designation D4566; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
DC Proof Test, Internal Shield (Screen)-to-shield 42
DC Proof Test, Other Required Isolations 43
1.1 These test methods cover procedures for electrical
DC Proof Test, Wire-to-wire 38
testing of thermoplastic insulations and jackets used on tele- Fault Rate Test (Air Core Only) 34
Insulation Resistance (IR) 33
communicationswireandcableandforthetestingofelectrical
Jacket Voltage Breakdown Rating Test 37
characteristics of completed products. To determine the proce-
Mutual Capacitance (CM) 19
dure to be used on the particular insulation or jacket Mutual Conductance 17
Phase Constant 45
compound, or on the end product, reference should be made to
Phase Delay 46
the specification for the product.
Phase Velocity 47
Resistance of Other Metallic Cable Elements 15
1.2 These test methods appear in the following sections of
Shorts Test (Continuity Between Wires of a Pair) 35
this standard:
Structural Return Loss and Return Loss 51
Unbalance Attenuation (Conversion Losses) 52
Test Method Sections
Voltage Surge Test 44
Electrical Tests of Insulation—In-process 5–9
DC proof test 9
1.3 The values stated in inch-pound units are to be regarded
Insulation Defect or Fault Rate 8
as standard. The values given in parentheses are mathematical
Spark Test 7
conversions to SI units that are provided for information only
Electrical Tests of Completed Wire and Cable 10–52
Attenuation 25
and are not considered standard.
Attenuation, Effects Due to Aging 32
Attenuation, Effects Due to Elevated Temperature 30 1.4 This standard does not purport to address all of the
Attenuation, Effects Due to Humidity 31
safety concerns, if any, associated with its use. It is the
Attenuation to Crosstalk Ratio—Far End (ACR-F) 29
responsibility of the user of this standard to establish appro-
Attenuation to Crosstalk Ratio—Near End (ACR-N) 27
Capacitance Deviation 20 priate safety, health, and environmental practices and deter-
Capacitance Difference 21
mine the applicability of regulatory limitations prior to use.
Capacitance Unbalance, Pair-to-ground (CUPG) 23
Specific hazard statements are given in Sections 7 and 38.
Capacitance Unbalance, Pair-to-pair (CUPP) 22
Capacitance Unbalance, Pair-to-support Wire 24 1.5 This international standard was developed in accor-
Characteristic Impedance—Test Method 1: Propagation Con- 48
dance with internationally recognized principles on standard-
stant and Capacitance
ization established in the Decision on Principles for the
Characteristic Impedance—Test Method 2: Single-ended Mea- 49
surements Development of International Standards, Guides and Recom-
Characteristic Impedance—Test Method 3: Least Squares 50
mendations issued by the World Trade Organization Technical
Function Fit
Barriers to Trade (TBT) Committee.
Coaxial Capacitance (Capacitance to Water) 18
Conductor Continuity 12
Conductor Resistance (CR) 14
2. Referenced Documents
Conductor Resistance Unbalance (CRU of Pairs) 16
2.1 ASTM Standards:
Continuity of Other Metallic Elements 13
Crosses Test (Continuity Between Wires of Different Pairs) 36
B193Test Method for Resistivity of Electrical Conductor
Crosstalk Loss, Far-end 28
Materials
Crosstalk Loss, Near-end 26
DC Proof Test, Core-to-internal Shield (Screen) 41 D150Test Methods forAC Loss Characteristics and Permit-
DC Proof Test, Core-to-shield 39
tivity (Dielectric Constant) of Solid Electrical Insulation
DC Proof Test, Core-to-support Wire 40
D1711Terminology Relating to Electrical Insulation
D2633Test Methods for Thermoplastic Insulations and
These test methods are under the jurisdiction of ASTM Committee D09 on
Electrical and Electronic Insulating Materials and are the direct responsibility of
Subcommittee D09.07 on Electrical Insulating Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2020. Published November 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1986. Last previous edition approved in 2014 as D4566–14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4566-20. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4566 − 20
Jackets for Wire and Cable 4.1.1 Warning—Lethal voltages are a potential hazard
D3426Test Method for Dielectric Breakdown Voltage and during the performance of this test. It is essential that the test
DielectricStrengthofSolidElectricalInsulatingMaterials apparatus, and all associated equipment electrically connected
Using Impulse Waves to it, be properly designed and installed for safe operation.
D5423Specification for Forced-Convection Laboratory Ov- 4.1.2 Solidly ground all electrically conductive parts which
ens for Evaluation of Electrical Insulation it is possible for a person to contact during the test.
E29Practice for Using Significant Digits in Test Data to 4.1.3 Provide means for use at the completion of any test to
Determine Conformance with Specifications ground any parts which were at high voltage during the test or
have the potential for acquiring an induced charge during the
2.2 ANSI Standard:
test or retaining a charge even after disconnection of the
ANSI/IEEE Standard 100IEEE Standard Dictionary of
voltage source.
Electrical and Electronics Terms
4.1.4 Thoroughly instruct all operators as to the correct
2.3 IEC Standard:
procedures for performing tests safely.
IEC 61156-1Multicore and Symmetrical Pair/Quad Cables
4.1.5 When making high voltage tests, particularly in com-
for Digital Communications—Part 1: Generic Specifica-
pressed gas or in oil, it is possible for the energy released at
tion
breakdown to be sufficient to result in fire, explosion, or
rupture of the test chamber. Design test equipment, test
3. Terminology
chambers, and test specimens so as to minimize the possibility
3.1 Definitions:
ofsuchoccurrencesandtoeliminatethepossibilityofpersonal
3.1.1 For definitions of terms used in this standard, refer to
injury. If the potential for fire exists, have fire suppression
Terminology D1711.
equipment available. Design test equipment, test chambers,
3.2 Definitions of Terms Specific to This Standard:
and test specimens so as to minimize the possibility of such
3.2.1 air core, n—refers to products in which the air spaces
occurrences and to eliminate the possibility of personal injury.
between cable core components (pairs, etc.) remain in their
See Section 4.
unfilled or natural state.
3.2.2 armored wire or cable, n—wire or cable in which the
5. Scope
shielded or jacketed or shielded and jacketed wire or cable is
5.1 In-process electrical tests are used primarily as process
completelyenclosedbyametalliccoveringdesignedtoprotect
control tools in an attempt to minimize the number and
the underlying telecommunications elements from mechanical
magnitude of problems detected at final test of completed
damage.
cable.
3.2.3 cable,telecommunications,n—productsofsixormore
pairs.
6. Significance and Use
3.2.4 filled core, n—those products in which air spaces are
6.1 Electrical tests, properly interpreted, provide informa-
filled with some materials intended to exclude air or moisture,
tion with regard to the electrical properties of the insulation.
or both.
The electrical test values give an indication as to how the
3.2.5 low frequency cable, n—cable used for transmitting
insulation will perform under conditions similar to those
signals at a frequency of 2 MHz or less.
observed in the tests. Electrical tests provide data for research
and development, engineering design, quality control, and
3.2.6 pair, n—two insulated conductors combined with a
acceptance or rejection under specifications.
twist.
3.2.7 sheath, n—the jacket and any underlying layers of
7. Spark Test
shield, armor, or other intermediate material down to but not
7.1 The spark test is intended to detect defects in the
including the core wrap.
insulation of insulated wire conductors. Spark testers are
3.2.8 shielded wire or cable, n—wire or cable in which the
commonly used to detect insulation defects (faults) at conduc-
core (or inner jacket) is completely enclosed by a metallic
tor insulating operations, at pair twisting operations, and
covering designed to shield the core from electrostatic or
(occasionally) at operations for assembly or subassembly of
electromagnetic interference, or both.
conductors. In selected instances, spark tests are used to detect
3.2.9 wire, telecommunications, n—productscontainingless
defects in the jackets of shielded wire and cable, and in such
than six pairs.
cases, spark testers appear on cable jacketing lines. The basic
method calls for a voltage to be applied between a grounded
ELECTRICAL TESTS OF INSULATION—IN-
conductor and an electrode that is in mechanical contact with
PROCESS
thesurfaceofthematerialbeingtested.Thewireorcableunder
test usually moves continuously against the electrode. When
4. Hazards
the dielectric medium is faulty (for example, excessively thin
4.1 High Voltage:
or missing, as in a pin-hole or when mechanically damaged),
the impressed voltage will produce an arc to the grounded
conductor. This arcing or sparking will usually activate one or
Available from Global Engineering Documents, 15 Inverness Way, East
Englewood, CO 80112-5704, http://www.global.ihs.com. more indicators (such as, warning buzzers or lights, counters,
D4566 − 20
etc.) and, when appropriately interlocked, are sometimes used 8.2 When appropriate, and using records of the quantity of
to halt the production or movement of the item through the product produced versus the number of insulation defects
spark tester electrode. For telecommunications products, the counted, a fault rate such as the following ratio is used:
number of faults is usually only counted while production
N 1
faultrate 5 5 (1)
continues.Jacketdefectsaresometimesflaggedwhendetected.
L X
Jacket defects and units of insulated wire containing an
where:
excessive number of faults are either repaired or disposed of.
N = number of faults detected,
7.2 Unless otherwise limited by detailed specification
L = length of the product over which the faults are detected,
requirements,sparktestersusedgenerateeitheranacordctest
and
voltage;ifac,oneormoreofvariousfrequenciesareused.For
X = average length of the product per fault.
safety to personnel, spark test equipment is usually current-
8.3 Fault rates are determined for any particular time frame
limited to levels normally considered to be non-lethal. Unless
asdesired;however,minimumindustrypracticeistokeepfault
otherwise specified, the test voltage level employed shall be at
rate records covering periods approximating one month, with
the discretion of the manufacturer.
cumulative records kept for six-month periods (for example,
7.3 Unless otherwise limited by detailed specification
for the first six months of the year, the fault rate was
requirements, various types of electrodes such as bead chains,
1/40 000 ft, meaning 1 fault/40000 conductor ft).
water, ionized air and spring rods are among electrode types
8.4 Report—Report in accordance with 7.5.
that have been successfully employed at the discretion of the
manufacturer. The length of the electrode is also variable;
8.5 Precision and Bias—The precision of this test has not
unless otherwise limited by detailed specification
been determined. No statement can be made about the bias of
requirements, electrode size and length shall be such that the
this test for insulation defect or fault rate since the result
tester will operate successfully for any particular rate of travel
merely states whether there is conformance to the criteria for
oftheproductthroughthetesterthatisused.Inspiteofcurrent
success specified in the product specification.
limitations, electrodes are normally provided with grounded
9. DC Proof Test—In-process
metallic screens or shields to guard against accidental person-
nel contact.
9.1 Forpurposesofin-processqualitycontrol,itisdesirable
to dc proof test product at one or more stages of processing
7.4 Both ends of the conductor of an insulated wire, or both
prior to the final test operation. Such testing is normally at the
endsofametallicshieldunderacablejacketaregrounded,and
discretion of the manufacturer.
then attached to the ground side of the tester. Attach the high
voltage side of the tester to the sparker electrode. Set the test
9.2 Conduct wire-to-wire dc proof tests in accordance with
voltage at the level specified. Unless otherwise specified,
Section 38 at a suitable stage of production as designated by
energize the spark tester whenever the product to be tested is
the factory management.
moving through the electrode. Take appropriate action (for
9.3 Report—Report in accordance with Section 53, except
example, flag defects, count defects, adjust the process, etc.)
that 53.1.5 does not apply.
when and if defects are detected.
9.4 Precision and Bias—The precision of this test has not
7.5 Report:
been determined. No statement can be made about the bias of
7.5.1 Report the following information recorded on suitable
this dc proof test since the result merely states whether there is
forms (that is, production reports):
conformance to the criteria for success specified in the product
7.5.1.1 Machine number and type (that is, extruder, twister,
specification.
etc.),
ELECTRICAL TESTS OF COMPLETED WIRE AND
7.5.1.2 Date of production test,
CABLE
7.5.1.3 Insulation type (air core or filled core), conductor
gauge and footage,
10. Scope
7.5.1.4 Voltage level, and
10.1 Electrical tests of completed wire and cable include
7.5.1.5 Number of indicated faults.
verification of some or all of the properties in accordance with
7.6 Precision and Bias—The precision of this test has not
Sections 12 through 52.
been determined. No statement can be made about the bias of
this spark test since the result merely states whether there is
11. Significance and Use
conformance to the criteria for success specified in the product
11.1 Electrical tests, properly interpreted, provide informa-
specification.
tion with regard to the electrical properties of the insulation or
of the jacket, or both. The electrical test values give an
8. Insulation Defect or Fault Rate—In-process
indication as to how the wire or cable, or both, will perform
8.1 Forpurposesofin-processqualitycontrol,itisdesirable under conditions similar to those observed in the tests. Elec-
tomonitorandrecordin-processfaultsataparticularoperation trical tests provide data for research and development, engi-
(such as, extruders, twisters, etc.) and relate the number of neering design, quality control, and acceptance or rejection
defects found to the quantity of product produced. under specifications.
D4566 − 20
12. Conductor Continuity 13.3 Report—Report in accordance with Section 53.
13.4 Precision and Bias—The precision of this test has not
12.1 Continuity of the conductors of a telecommunications
been determined. No statement can be made about the bias of
wire and cable is a critical characteristic.
this test for continuity of other metallic cable elements since
12.2 Unless otherwise specified or agreed upon, conductor
the result merely states whether there is conformance to the
continuity shall be verified using a dc potential of 100 V or
criteria for success specified in the product specification.
less. Manual continuity checkers commonly take a form of a
batteryvoltagesourceof9V,inserieswithavisibleoraudible
14. Conductor Resistance (CR)
indicator with hand-held test leads.Automatic test equipment,
14.1 The conductor resistance (CR) in telecommunications
also available to test properly terminated wire and cable,
wire and cable is a key characteristic; however, conductor
normally provides an indication (lights or printout) when
resistance is normally verified only on a quality assurance
continuity does not exist.
sampling basis for finished products. Complete shipping units
12.3 Prepare each end of the wire or cable for test. This
(full reels or other) of wire or cable, or both (not specimen
usuallyinvolvesstrippingsomeinsulationfromeachconductor
lengths) shall constitute the basic sample. When the selected
at each end and separating the conductors at one or both ends.
sample reel is a cable containing a great many conductors, the
When automatic test equipment is used, terminate the indi-
conductors of the sample cable are also checked on a sampling
vidual conductors at a test fixture (both ends are normally
basis (that is, sampling of the sample).
terminated since this automatic test is often performed in
14.2 Unless otherwise specified or agreed upon, measure
conjunction with other tests). When manual continuity check-
the dc conductor resistance (CR) at or corrected to 20 °C
ingisperformed,itisusuallysuitabletoconnectallconductors
(68 °F). Temperature correction shall be performed as de-
to a common termination (for example, wrap stripped ends
scribed in Test Method B193. The dc resistance is considered
with a length of copper wire, immerse one end in an electri-
to vary directly with cable length.
cally conductive liquid, etc.) at one end of the wire or cable.
14.3 Conductor resistance measurements are commonly
12.4 In succession, apply the voltage source to one end of
made using volt/ohm meters or Wheatstone bridges having an
each conductor. Use test equipment indicators to verify the
accuracy of 60.5%. Various types of automatic or semiauto-
continuous circuit paths or detect the discontinuities.
matic equipment are also used.
12.5 After defective conductors are repaired, continuity
14.4 Followthegeneralproceduresof12.3through12.5for
checks must be repeated.
end preparation followed by measurement using the voltage
supplied by the test instrument. Record instrument readings
12.6 Report—Report in accordance with Section 53.
obtainedforeachtestedconductor.Notethatdataforresistance
12.7 Precision and Bias—The precision of this test has not
unbalancetesting(Section16)isnormallyobtainedduringthis
been determined. No statement can be made about the bias of
procedure; consequently, care must usually be taken to record
this test for conductor continuity since the result merely states
data separately in pair groupings. See Section 16 for details.
whether there is conformance to the criteria for success
14.5 Upon completion of measurements, manipulate the
specified in the product specification.
recordeddataasappropriate(forexample,determineaverages,
adjust for temperature and length, etc.) and compare with the
13. Continuity of Other Metallic Cable Elements
requirements of detailed specifications.
13.1 In addition to the metallic conductors intended for
14.6 Report:
information transmission, telecommunications wire and cable
14.6.1 ReportinaccordancewithSection53andincludethe
constructions sometimes contain one or more additional me-
following:
tallic elements in the form of a shield, armor, or an internal
14.6.1.1 Minimum, maximum and average values, and
shield or screen that separates a cable into compartments, etc.
14.6.1.2 Ambient temperature.
Depending upon the particular product design, these elements
are sometimes in contact with each other (cross-continuity).
14.7 Precision and Bias—The precision of this test has not
The continuity of each of these elements is normally consid- been determined. No statement can be made about the bias of
ered to be a critical parameter.
this test for conductor resistance since the result merely states
whether there is conformance to the criteria for success
13.2 Unless otherwise specified or agreed upon, verify the
specified in the product specification.
individual continuity of each shield, armor, screen (internal
shield), or other metallic cable element of the cable construc-
15. Resistance of Other Metallic Cable Elements
tion using a dc potential of 100 V or less, in accordance with
15.1 It is occasionally important to know the resistance of
Section 12. When metallic elements under test are insulated,
other metallic elements (most often shield resistance) within
the insulation is normally removed to the extent necessary for
telecommunications wire and cable.When required, this infor-
testing. If continuity between any of these metallic elements is
mation is obtained by following the procedure of 14.2 through
required, it shall be verified; if such continuity is expected but
14.4, measuring cable construction elements as appropriate.
not required, it is verified at the discretion of the manufacturer.
If continuity between any of these metallic elements is not 15.2 Report—Report in accordance with Section 53 and
permitted, verify isolation in accordance with Section 43. include the ambient temperature.
D4566 − 20
15.3 Precision and Bias—The precision of this test has not conductanceofanindividualpairvariesasmuchas10to15%
been determined. No statement can be made about the bias of from the nominal values at carrier frequencies. The effect of
thistestforresistanceofothermetalliccableelementssincethe conductanceonthesecondaryparametersisnegligibleatvoice
resultmerelystateswhetherthereisconformancetothecriteria frequency, and contributes less than 1% to the secondary
for success specified in the product specification. parameters at 1 MHz, so the inconsistency is of little conse-
quence. Although conductance also varies with temperature,
16. Conductor Resistance Unbalance (CRU of Pairs)
thecorrectionisinsignificantincomparisonwithothersources
16.1 Thedifferenceinresistancebetweentwoconductorsof of variation, so it is usually neglected.
any pair is sometimes a key characteristic in telecommunica-
17.2 Because of the constraints mentioned in 17.1, mutual
tions; however, Conductor Resistance Unbalance (CRU) is
conductance is only measured rarely, and readings are usually
normally verified only on a quality assurance sampling basis
taken on short specimen lengths (an exact 32-ft specimen is
for finished products.
convenient). When an impedance bridge is used for
measurements, conductance and capacitance are read directly
16.2 The conductor resistance unbalance is usually deter-
minedatthesametimethatconductorresistancemeasurements from the instrument balance settings. Various types of auto-
aremade;consequently,14.2through14.5applyandresistance matic or semiautomatic equipment are also used.
data is recorded in pair groupings.
17.3 Unless otherwise specified, obtain mutual conductance
16.3 The absolute difference in resistance unbalance is readings at 23 6 3 °C and a test frequency of 1000 6 100 Hz.
Measured values are normally converted to a standard length
calculated by subtracting the lesser resistance from the greater
resistance. Absolute resistance unbalance is normally ex- value (normally one mile or one km). For conductance in
micro-Siemens per mile, the values would be:
pressed in Ω/1000 ft or Ω/km. A more useful and generally
used expression for resistance unbalance is percent resistance
G 35280
G 5 µS/mile (3)
unbalance, where: o
L
R 2 R
max min
CRU 5 ·100% (2)
G 31000
R
min
G 5 µS/km
o
L
where:
where:
CRU = conductor resistance unbalance in %,
G = mutual conductance, µS/mile (km),
o
R = maximum conductor resistance of a conductor in a
max
G = conductance reading, µS, and
pair, and
L = specimen length, ft (m).
R = minimum conductor resistance of a conductor in a
min
pair.
17.4 Report—Report in accordance with Section 53 and
NOTE 1—Care must be taken to identify the method for determining
include the maximum value.
conductorresistanceunbalance.IEC61156-1definesconductorresistance
17.5 Precision and Bias—The precision of this test has not
unbalance as the ratio of the difference in resistance of two conductors to
the sum of their resistances. Therefore, the IEC values are less than half been determined. No statement can be made about the bias of
of those defined in 16.3.
this test for mutual conductance since the result merely states
whether there is conformance to the criteria for success
16.4 Telecommunicationswireandcableusersaregenerally
specified in the product specification.
interested in two resistance unbalance values; cable average
and maximum individual pair unbalance. Cable average in
18. Coaxial Capacitance (Capacitance to Water)
absolute or percentage terms is determined by standard aver-
18.1 Coaxialcapacitanceforinsulatedwireisdefinedasthe
aging techniques, while the maximum individual pair unbal-
capacitance existing between the outer surface of the round
ance in absolute or percentage terms is determined by simple
metallic conductor and the outer surface of the insulating
inspection of the data. Data values are then compared with
dielectric applied over that conductor.
detailed specification requirements to verify conformance.
16.5 Report—Report in accordance with Section 53 and NOTE 2—For a more general definition, refer to Test Methods D150 or
to Terminology D1711.
include the average and maximum values.
18.2 In-process measurements of coaxial capacitance are
16.6 Precision and Bias—The precision of this test has not
made by passing the insulated conductor through a water bath
been determined. No statement can be made about the bias of
whilemeasurementsaremadebetweenthegroundedconductor
this test for conductor resistance unbalance (pairs) since the
and the water. Automatic feedback of data is then used to
resultmerelystateswhetherthereisconformancetothecriteria
control the insulating equipment. Such measurements are
for success specified in the product specification.
generally not suitable for product acceptance.
17. Mutual Conductance
18.3 For purposes of measuring coaxial capacitance in
17.1 The mutual conductance of a pair in a wire or cable is completed wire, a sample of insulated wire is immersed in a
proportionaltothemutualcapacitance,theaveragevalueofthe water bath and the direct capacitance is measured between the
effective dissipation factor of the insulating system, and the conductor and the water. Unless otherwise specified perform
frequency. Although it is one of the primary transmission measurements at a water temperature of 20 6 2 °C and a test
characteristics, mutual conductance is the least consistent; the frequency of 1000 6 100 Hz using capacitance or impedance
D4566 − 20
bridges, capacitance meters, etc. Use this or other equipment 19.6 Specification limits are generally placed on the cable
that yields equivalent capacitance results. average mutual capacitance and on the individual pair mutual
capacitance. Limits for individual pairs can be verified only by
18.4 Report—Report in accordance with Section 53 and
making measurements of individual pairs, and such measure-
include the minimum, maximum and average values.
ments are normally made for cables of 25 or fewer pairs; for
18.5 Precision and Bias—The precision of this test has not
larger cables, individual measurements are often made only on
been determined. No statement can be made about the bias of
a quality assurance sampling basis. Cable averages can be
thistestforcoaxialcapacitance(capacitancetowater)sincethe
obtained by averaging individual pair readings. Average mu-
resultmerelystateswhetherthereisconformancetothecriteria
tualcapacitancecanalsobemeasuredbygroupinganumberof
for success specified in the product specification.
pairs together (electrical in parallel circuits), measuring the
capacitance of the group and dividing the total capacitance by
19. Mutual Capacitance (CM)
the number of pairs tested to obtain a grouped average. When
19.1 Mutual capacitance (CM) is defined as the effective
grouped readings are made, no more than 25 pairs should be
capacitance between the two wires of a pair. In a multi-pair
grouped for any one reading. Conversely, grouped readings
cable, the mutual capacitance is defined as:
should not be used for cables containing 25 or fewer pairs.
C ·C
19.7 Unless otherwise specified, measure mutual capaci-
AG BG
CM 5 C 1 nF/cablelength (4)
AB
C 1C
tanceat23 63°C.Measuredvaluesarenormallyconvertedto
AG BG
a standard length value (normally 1 mile or 1 km). For mutual
where:
capacitance in nano-Farad/mile, the values would be:
CM = mutual capacitance, and
C 35280
C , C , and C are as illustrated in Fig. 1.
AB AG BG
C 5 nF/mile (5)
o
L
19.2 Mutual capacitance is a critical characteristic in tele-
communications wire and cable; consequently, unless other-
C 31000
C 5 nF/km
o
wise specified or agreed upon between the producer and the
L
user, each lot of product is checked to verify this parameter.
where:
19.3 Before measuring, the cable to be tested must be
C = mutual capacitance, nF/mile (nF/km),
o
prepared by removing the jacket(s) and shield or armor, when
C = mutual capacitance, measured, nF, and
present, from both ends of the cable to expose approximately
L = specimen length, ft (m).
2 ft (600 mm) of the cable core. Conductors at one end of the
NOTE 3—This test method is applicable for lengths of 10000 ft (3.05
cable are then fanned out to ensure that no conductors are
km) or less. Special correction factors are required for longer lengths.
shorted or grounded. Insulation is then stripped for approxi-
19.8 Report:
mately1to3in.(25to75mm)fromtheconductorsattheother
19.8.1 ReportinaccordancewithSection53andincludethe
end of the cable.All conductors are then shorted together and
following:
togroundtodissipateanystaticchargethataccumulatedonthe
19.8.1.1 Minimum, maximum, and average values, and
conductors.
19.8.1.2 Standard deviation.
19.4 Unless otherwise specified, mutual capacitance is un-
19.9 Precision and Bias—The precision of this test has not
derstood to mean capacitance at a test frequency of 1000 6
been determined. No statement can be made about the bias of
100Hz,andthistestfrequencyshallbeusedifmeasurementis
this test for mutual capacitance since the result merely states
made using a bridge technique. Other test methods yielding
whether there is conformance to the criteria for success
comparable results shall be considered as acceptable if not
specified in the product specification.
specifically prohibited.
20. Capacitance Deviation
19.5 Mutual capacitance readings are commonly made
manually using impedance bridges or capacitance meters; 20.1 The desired intent of most telecommunications cable
various types of automatic or semiautomatic equipment are specifications is to have an individual pair mutual capacitance
also used. and a reel average mutual capacitance as close to the specified
FIG. 1 Mutual Capacitance Relationships
D4566 − 20
nominal requirement as possible. It is also intended that 21.2 Using the test methods described in Sections 14 and
differences between reels of cable of different wire gages and 19, measure the conductor resistance and mutual capacitance
of different pair counts should be kept to a minimum. The
of individual pairs selected at random, keeping separate re-
capacitance deviation for any reel of cable is defined as the
cordsforpairsfromtheinnerlayerandforpairsfromtheouter
calculated root mean square deviation of the mutual capaci-
layer. When measuring compartmental core cable, make mea-
tance of all the measured pairs of the reel of cable from the
surements in each compartment separately. Unless otherwise
average mutual capacitance for that reel of cable.
permitted the number of inner and outer pair readings shall
each be at least 5% of the total pair count, or 25 readings,
20.2 Using the test methods described in Section 19, mea-
whichever is less.
sure the individual pair mutual capacitances. (This test method
cannot be applied to grouped mutual capacitance readings.)
21.3 Calculatetheaverageconductorresistanceandaverage
Calculate the capacitance deviation from the measured data
mutual capacitance for the innermost pairs (center layer) and
using the following equation:
record as (R and C , respectively). Repeat this calculation for
1 1
σ
the outermost pairs and record as (R and C , respectively).
o o
D 5 3100% (6)
xH
21.4 Calculate the percent difference, D, in the average
where:
mutualcapacitancefortheinnermostandoutermostpairsusing
D = % root mean square (rms) deviation from average,
the following equation:
σ =
C 2 C R 2 R
x x
o 1 o 1
(
D 5 2 ·100% (7)
Π2S D ,
(
C R
N N
o o
21.4.1 The calculated percentage difference for any mea-
x¯ =
x
(
sured cable shall comply with the requirements of the product
,
N
specification.
x = individual mutual capacitance values (nF/mile, nF/kft,
21.5 Report—Report in accordance with Section 53.
nF/km, etc.), and
21.6 Precision and Bias—The precision of this test has not
x¯ = average mutual capacitance value (nF/mile, nF/kft,
been determined. No statement can be made about the bias of
nF/km, etc.).
thistestforcapacitancedifferencesincetheresultmerelystates
20.2.1 The calculated percentage deviation for any mea-
whether there is conformance to the criteria for success
sured cable shall comply with the requirements of the product
specified in the product specification.
specification.
20.3 Report—Report in accordance with Section 53 and
22. Capacitance Unbalance—Pair-to-Pair (CUPP)
include the percent deviation.
22.1 Thecapacitancesinvolvedandthedefinitionofcapaci-
20.4 Precision and Bias—The precision of this test has not
tance unbalance pair-to-pair (CUPP) are illustrated in Fig. 2,
been determined. No statement can be made about the bias of
whereAandBrepresentthetwoconductorsofapairandCand
thistestforcapacitancedeviationsincetheresultmerelystates
D represent the two conductors of another pair.
whether there is conformance to the criteria for success
22.1.1 The capacitances, namely C , C , C , and C
AC AD BC BD
specified in the product specification.
are the direct capacitances between conductors. Direct capaci-
21. Capacitance Difference (Filled Core Only)
tance is defined in ANSI/IEEE Standard 100-1984.
22.1.2 The capacitances, C , C , C , and C are the
21.1 Use this test to provide some assurance that a filled
AG BG CG DG
direct capacitances between wires A, B, C and D respectively,
cable is adequately filled across the entire cross-section of the
and all other conductors and shields in the cable that are
cable core. This test can be applied only to cables that are
manufactured with a clearly discernible center layer of pairs. connected to grounded.
FIG. 2 Conductor Capacitances
D4566 − 20
22.2 Measure the capacitance unbalance, pair-to-pair at a 23. Capacitance Unbalance—Pair-to-ground (CUPG)
test frequency of 1000 6 100 Hz using a capacitance unbal-
23.1 Thecapacitancesinvolvedandthedefinitionofcapaci-
ance bridge. Use any suitable type of automatic and semiau-
tance unbalance, pair-to-ground (CUPG) are illustrated in Fig.
tomatic equipment for this measurement.
3, where A and B represent the two conductors of a pair. The
capacitances, namely C and C are the direct capacitances
22.3 In cables of 25 pairs or less and in each group of
AG BG
between conductors A and B respectively and the shield. The
multi-group cables, the unbalances to be considered are all of
capacitances C and C are the direct capacitances between
the following:
AP BP
conductors A and B respectively and all other pairs P, consist-
22.3.1 Between pairs adjacent in a layer,
ing of the conductors’ u, v and x, y respectively.
22.3.2 Betweenpairsinthecenter,whentherearefourpairs
or less, and 23.2 Using a capacitance unbalance bridge, measure the
pair-to-ground capacitance unbalance at a test frequency of
22.3.3 Betweenpairsinadjacentlayers,whenthenumberof
1000 6 100 Hz. Use any suitable type of automatic and
pairs in the inner (smaller) layer is six or less. Here, the center
semiautomatic equipment for this measurement.
is counted as a layer.
23.3 If a capacitance unbalance bridge is not available, the
22.4 If a capacitance bridge is not available, the direct
direct capacitances (refer to 23.1) C , C , C , and C can
AG BG AP BP
capacitances (refer to 22.1) C , C , C , and C can be
AC AD BC BD
be measured using a voice-frequency capacitance bridge or
measured using a voice-frequency capacitance bridge or com-
comparable equipment. The capacitance unbalance, pair-to-
parable equipment. The capacitance unbalance, pair-to-pair
ground, CUPG, can then be calculated using the following
(CUPP), can then be calculated using the following equation:
equation:
CUPP 5 ~C 1C ! 2 ~C 1C ! pFatcablelength (8)
AD BC AC BD
CUPG 5 C 1C 2 C 2 C pF/cablelength (10)
~ ! ~ !
AG AP RG RP
22.5 Unless otherwise specified, correct the maximum,
23.4 Unless otherwise specified correct the maximum and
average, and root mean square unbalance values for each
average capacitance unbalance values for each length, other
lengthotherthat1000ft(or1000m)to1000ft(or1000m)by
that1000ft(or1000m),to1000ft(or1000m)bydividingthe
dividing the value of unbalance for the length measured by the
value of unbalance for the length measured by the ratio of the
square root of the ratio of the length measured to 1000.
length measured to 1000.
Y
Y 5 pFat1000ft 1000m (9) Y
~ !
Y 5 (11)
=X/1000
X/1000
where:
where:
Y = unbalance corrected to 1000 ft (1000 m),
Y = unbalance corrected to 1000 ft (1000 m),
Y = unbalance of cable length, and
Y = unbalance of cable length, and
X = cable length, ft (m).
X = cable length, ft (m).
22.6 Report—Report in accordance with Section 53 and
23.5 Report—Report in accordance with Section 53 and
include the maximum, average, and root mean square values.
include the maximum and average values.
22.7 Precision and Bias—The precision of this test has not 23.6 Precision and Bias—The precision of this test has not
been determined. No statement can be made about the bias of been determined. No statement can be made about the bias of
thistestforcapacitanceunbalance(pair-to-pair)sincetheresult this test for capacitance unbalance (pair-to-ground) since the
merely states whether there is conformance to the criteria for resultmerelystateswhetherthereisconformancetothecriteria
success specified in the product specification. for success specified in the product specification.
FIG. 3 Pair-to-ground Capacitance Unbalance
D4566 − 20
24. Capacitance Unbalance—Pair-to-support Wire attenuation shall be defined as:
24.1 This particular procedure is applied only to self- 1 V
iN
α 5 · 20·log dB/lengthunit (12)
U U
i 10
supported (that is, integral messenger wire) non-shielded L V
o iF
telecommunications wire and cable.
where:
24.2 Unbalances shall be measured as described in Section
L = measured length of the cable in length units, and
o
23,exceptthatthegroundedsupportwirereplacestheshieldin
α = attenuation of the pair i.
i
all measurements. The maximum allowable unbalances shall
25.2 Cable ends shall be prepared as described in 26.2.
comply with the requirements of the product specification.
25.3 The equipment used for measuring attenuation, unless
24.3 Report—Report in accordance with Section 53 and
otherwise specified, shall be (a) balanced to ground, or (b) a
include the maximum value.
network analyzer with an S-parameter test set in conjunction
24.4 Precision and Bias—The precision of this test has not
with balance to unbalanced impedance matching transformers
been determined. No statement can be made about the bias of
(baluns). In the case (a), the test equipment shall have a
this test for capacitance unbalance (pair-to-support wire) since
nominal input and output impedance corresponding to the
the result merely states whether there is conformance to the
nominalcharacteristicimpedance 61%ofthepairsundertest.
criteria for success specified in the product specification.
The input power to the pair under test shall be approximately
10 dBm. The circuit of Fig. 5, or equal, shall be used.
25. Attenuation
25.1 Attenuation is a measure of the loss in signal strength 25.4 Unless otherwise specified, measure attenuation at or
over a length of wire or cable and is affected by the materials corrected to 20 °C (68 °F). Temperature corrections can be
and geometry of the insulated conductors, the surrounding made using the following equations, taking into account the
jacket material and/or eventual shield(s). Referring to Fig. 5, copper conductor resistance increase with temperature:
(a) Attenuation temperature correction factor for temperatures given in °C.
(b) Attenuation temperature correction factor for temperatures given in °F.
FIG. 4 Attenuation Temperature Correction Factor
D4566 − 20
NOTE 1—Source impedance = Z 61%.
o
NOTE 2—Pairs not under test terminated with resistors = Z 610%.
o
NOTE 3—Terminating resistors Z shall be non-inductive.
o
FIG. 5 Test Circuit for Crosstalk Measurements
α α this test for attenuation since the result merely states whether
T T
α 5 5 dB/lengthunit(13)
110.0022· T 2 20 TCFin °C there is conformance to the criteria for success specified in the
@ ~ !#
product specification.
α 5 α ·TCFin °C dB/lengthunit
T 20
26. Crosstalk Loss—Near End
where:
α = attenuation corrected to 20 °C, 26.1 Near-end crosstalk loss (NEXT) is usually defined and
α = measured attenuation at temperature T, measuredasaninput-to-outputcrosstalkcouplingbetweentwo
T
T = measured temperature, °C, and
pairs on the same end of the cable. Hence, NEXT is the
TCF = temperature correction factor at temperature T in °C.
logarithmic ratio of the input power of the disturbing pair i to
the output power of the disturbed pair j on the same end of the
α α
T T
α 5 5 dB/lengthunit (14) cable. Referencing Fig. 5, the NEXT shall be defined as:
@110.0012·~T 2 68!# TCFin °F
V
iN
NEXT 5 20·log dB (15)
U U
α 5 α ·TCFin °F dB/lengthunit ij 10
T 68 V
jN
where:
where:
α = attenuation corrected to 68 °F,
68 NEXT = NEXT measured, dB,
ij
α = measured attenuation at temperature T,
T i = disturbing pair,
T = measured temperature, °F, and
j = disturbed pair,
TCF = temperature correction factor at temperature T in °F.
V = inputvoltagetothedisturbingpairatthenearend,
iN
NOTE4—Whenthetemperaturecoefficientoftheattenuationincreaseis
and
higher than the increase due to resistance increase of the copper conduc-
V = output voltage of the disturbed pair at the near
jN
tors alone, the coefficient has to be determined, see Section 30.
end.
25.5 Alternately, the information given in Fig. 4(a) and Fig.
26.1.1 To correct crosstalk values to the nominal character-
4(b)issometimesusedforperformingtemperaturecorrections.
istic impedance, when the terminating and characteristic im-
Measured values are normally converted to a standard length
pedance are different, Eq 15 is changed as follows:
value (normally 1 mile, 1000 ft, or 1 km). Attenuation is
V 4Z ·Z
considered to vary directly with length. The correction factors
iN o
NEXT 5 20·log 120·log dB (16)
U U
ij 10 10 2
are based on Eq 13 and 14. V ~Z 1Z!
jN o
25.6 Upon completion of measurements, mathematically
where:
manipulate the recorded data as appropriate (for example,
Z = nominal characteristic impedance of cable, and
o
determine averages, adjust for temperature and length, etc.)
Z = terminating impedance at the far end of both pairs.
and compare with the requirements of detailed specifications.
26.2 Cable ends shall be prepared for test as described in
25.7 Report:
19.3 for low frequency cables. For cables intended to be used
25.7.1 ReportinaccordancewithSection53andincludethe
at frequencies beyond 2 MHz, the cable ends shall be kept to
following:
the minimum length that will permit a connection to the test
25.7.1.1 Minimum, maximum, and average values, and
equipment.
25.7.1.2 Ambient temperature.
26.3 The equipment used for measuring crosstalk, unless
25.8 Precision and Bias—The precision of this test has not otherwise specified, shall be (a) balanced to ground, or (b) a
been determined. No statement can be made about the bias of network analyzer (NWA)
...