ASTM B794-97(2009)
(Test Method)Standard Test Method for Durability Wear Testing of Separable Electrical Connector Systems Using Electrical Resistance Measurements
Standard Test Method for Durability Wear Testing of Separable Electrical Connector Systems Using Electrical Resistance Measurements
SIGNIFICANCE AND USE
Materials for electrical connector contacts must satisfy a number of requirements in the areas of electrical, mechanical, and economic characteristics. The stability of electrical properties is one of the most important of these characteristics. Wear of contact surfaces may adversely affect these electrical properties, especially in designs where the contact surfaces are relatively thin coatings. This test method provides a means to compare various material systems on a basis relevant to their application in electrical connector contacts.
Repeated insertion and withdrawal of a connector may cause wear or other mechanical damage to the electrical contact surfaces, rendering those surfaces more susceptible to environmental degradation. This test method is intended to detect degradation of the electrical properties of the connector by such processes.
This test method describes procedures for conducting wear and durability testing of electrical connectors; the procedures produce quantitative results. These results may be used to compare the performance of different connector designs so that meaningful design choices can be made. Such results may also be used to compare the performance of a connector to a previously established standard to evaluate the quality of the samples under test.
The test results obtained from this test method are limited in their applicability to connector combinations that are equivalent in design and manufacture to those actually tested.
The user is cautioned that the conditions in this test should be compared to the conditions that the connector will experience in the intended application in order to determine the relevance of this test method to the particular needs of the user. For example, the environmental stress in this test method is less severe than certain industrial and marine environments and therefore test results are not directly applicable to predict the performance of product intended for use in such areas.
It is recomm...
SCOPE
1.1 This test method covers the effects of repeated insertion and withdrawal of separable electrical connectors which are harmful to the electrical performance of the connector.
1.2 This test method is limited to electrical connectors designed for use in applications where the current through any one connection in the connector does not exceed 5 A, and where the connector may be separated a number of times during the life of the connector.
1.3 This test method is limited to electrical connectors intended for use in air ambients where the operating temperature is less than 65°C.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
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Designation: B794 − 97(Reapproved 2009)
Standard Test Method for
Durability Wear Testing of Separable Electrical Connector
Systems Using Electrical Resistance Measurements
This standard is issued under the fixed designation B794; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Summary of Test Method
1.1 This test method covers the effects of repeated insertion
3.1 Sample connectors are wired for precision resistance
and withdrawal of separable electrical connectors which are
measurements of each test contact. The samples are divided
harmful to the electrical performance of the connector.
into two groups; then resistance measurements are made of
each test contact. The connectors in one group undergo a
1.2 This test method is limited to electrical connectors
designed for use in applications where the current through any number of insertion/withdrawal cycles appropriate for the
one connection in the connector does not exceed 5 A, and particular connector under test, and the resistances of these
where the connector may be separated a number of times connectors are measured again. The connectors in the other
during the life of the connector. group are not disturbed. All samples are subjected to an
accelerated aging test; then the resistances are measured again.
1.3 This test method is limited to electrical connectors
All samples are separated (withdrawn), exposed to an acceler-
intended for use in air ambients where the operating tempera-
ated aging test in the uninserted condition, removed from the
ture is less than 65°C.
test, reinserted, and resistances measured again. The various
1.4 The values stated in SI units are to be regarded as
resistance measurements are compared to detect effects of the
standard. No other units of measurement are included in this
wear and aging on electrical performance.
standard.
1.5 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
4.1 Materials for electrical connector contacts must satisfy a
responsibility of the user of this standard to become familiar
number of requirements in the areas of electrical, mechanical,
with all hazards including those identified in the appropriate
and economic characteristics. The stability of electrical prop-
Material Safety Data Sheet (MSDS) for this product/material
erties is one of the most important of these characteristics.
as provided by the manufacturer, to establish appropriate
Wear of contact surfaces may adversely affect these electrical
safety and health practices, and determine the applicability of
regulatory limitations prior to use. properties, especially in designs where the contact surfaces are
relatively thin coatings. This test method provides a means to
2. Referenced Documents
compare various material systems on a basis relevant to their
2.1 ASTM Standards:
application in electrical connector contacts.
B539 Test Methods for Measuring Resistance of Electrical
4.2 Repeated insertion and withdrawal of a connector may
Connections (Static Contacts)
3 cause wear or other mechanical damage to the electrical
2.2 Military Standard:
contact surfaces, rendering those surfaces more susceptible to
MIL-STD-1344A Test Methods for Electrical Connectors
environmental degradation. This test method is intended to
detect degradation of the electrical properties of the connector
This test method is under the jurisdiction of ASTM Committee B02 on
by such processes.
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.11 on Electrical Contact Test Methods.
4.3 This test method describes procedures for conducting
Current edition approved April 15, 2009. Published April 2009. Originally
approved in 1988. Last previous edition approved in 2003 as B794 – 97 (2003).
wear and durability testing of electrical connectors; the proce-
DOI: 10.1520/B0794-97R09.
dures produce quantitative results. These results may be used
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
to compare the performance of different connector designs so
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
that meaningful design choices can be made. Such results may
the ASTM website.
also be used to compare the performance of a connector to a
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
previously established standard to evaluate the quality of the
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
www.dodssp.daps.mil. samples under test.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B794 − 97 (2009)
4.4 The test results obtained from this test method are dure __ , shall meet the limits in the supplied table.” This table
limited in their applicability to connector combinations that are supplied by the purchaser may set limits on all of the values in
equivalent in design and manufacture to those actually tested. Fig. 1, or only on a subset of those values that the purchaser
deems adequate to ensure the performance of the product.
4.5 The user is cautioned that the conditions in this test
should be compared to the conditions that the connector will
5. Apparatus
experienceintheintendedapplicationinordertodeterminethe
5.1 Environmental Test Chamber, capable of controlling the
relevance of this test method to the particular needs of the user.
testambientinaccordancewiththesequenceshowninTable1.
For example, the environmental stress in this test method is
The test chamber shall be sufficiently large that each test
lessseverethancertainindustrialandmarineenvironmentsand
sample shall be positioned with at least 100 mm separating it
therefore test results are not directly applicable to predict the
from the nearest wall of the test chamber. The test chamber
performance of product intended for use in such areas.
design and operation procedure shall conform to the require-
4.6 It is recommended that this test method be used in one
ments contained in MIL-STD-1344A, Method 1002.2.
of two ways. First, it may be used to evaluate and report the
5.2 An instrument is required for measuring resistance by
performance of a particular connector system. In such a case,
the four-wire method. This instrument shall operate within the
it is appropriate to report the results in a table in the format
limits on current and open-circuit voltage set forth in Test
shown in Fig. 1 and to state “The results shown in the table
Methods B539, Test Method C. The instrument shall be
were obtained for (insert connector designation or description)
capable of measuring a resistance less than 0.100 Ω with a
when tested in accordance with ASTM Standard B794,
resolution of 0.0001Ω. For a resistance 0.100Ω or larger, the
Method __ , Procedure __ .” Second, it may be used to impose
instrument shall be capable of measuring it with a resolution of
requirements for acceptance of product. In this case, limits for
0.1 % of the resistance value.
the values shown in Fig. 1 must be established prior to product
acceptance testing. Such limits may be established by various
6. Sampling and Test Specimens
methodssuchasbyevaluationofproductwhichisknowntobe
6.1 Selection of Sample Connectors—Obtain sufficient
acceptable or by application of appropriate experience. These
sample connectors so that the electrical resistance of at least
limits must be documented in a manner that the entity
200 contacts contained in at least 20 separate connectors will
performing the product test can refer to the limits to determine
be measured in the test. Obtain sample connectors that are
if the test product conforms to such limits. A purchaser may
representative of those that will be used in the intended
wish to supply a table of limits and include on the purchase
application. Recognize that a connector consists of two halves
order a statement similar to: “The product, when tested in
and both halves must be representative of the product to be
accordance with ASTM Standard B794, Method __ , Proce-
used. In some cases one half will be a conductive area or pad
on a printed wiring-board surface, therefore printed wiring
boards must be obtained that have representative conductive
pads. Specifically, the conductive pads shall be manufactured
to the same requirements as those that will be required of parts
to be used in the system application. These requirements will
normally cover the manufacturing process, thickness,
composition,hardness,androughnessofboththefinishcoating
and of any underplating or undercoating. Protective treatments,
if used, shall also be specified. For the purpose of connector
testing, such printed wiring boards are generally fabricated
with appropriate circuitry to permit four-wire resistance mea-
surements.
6.2 Selection of Sample Contacts—In the case where the
samples are multicontact connectors and electrical measure-
ments are performed only on a fraction of the total number of
TABLE 1 Environmental Test Sequence
NOTE 1—Tolerance on temperature control is ±2°.
Step Elapsed Time, Temperature, Relative Humidity,
h °C %
1 0–2.5 ascending, 25–65 92 ± 3
2 2.5–5.5 65 92 ± 3
3 5.5–8 descending, 65–25 87 ± 8
4 8–10.5 ascending, 25–65 92 ± 3
5 10.5–13.5 65 92 ± 3
6 13.5–16 descending, 65–25 87 ± 8
7 16–24 25 92 ± 3
FIG. 1 Sample Format for Reporting Results
B794 − 97 (2009)
contacts, the contacts measured shall be distributed throughout and refer to these as the “wear test samples.” Insert the other
the field of contacts. Measure the corresponding contacts in halfoftheconnectorsonlyonceatthebeginningofthetestand
each sample connector. refer to these as the “control samples.”
8.3 Methods and Procedures for Resistance Measurements:
7. Conditioning
8.3.1 Prepare data sheets such that all information shown in
7.1 An electrical measurement laboratory is required in the sample data sheet illustrated in Fig. 2 may be recorded for
each test contact.
which the ambient temperature is controlled to 23 6 5°C and
the relative humidity is held below 60 %. This laboratory need 8.3.2 Perform all electrical measurements and wear tests in
the electrical measurements laboratory discussed in Section 7.
not be dedicated to this test program to the exclusion of other
uses so long as those other uses do not degrade the quality of Test samples must be allowed to come to equilibrium in this
data obtained on the connector test samples. ambient for a minimum of 1 h before electrical measurements
or connector insertion/withdrawal operations begin. All con-
nector insertion/withdrawal operations are done with the con-
8. Procedure
nector disconnected from any power source.
8.1 Selection of Test Method—Select a test method from the
8.3.3 Perform all resistance measurements under dry-circuit
following table which is appropriate for connector design and
conditions as specified in Test Methods B539, Test Method C.
application.
In addition, use a suitable method to cancel small potentials
Method Number of Insertions
that may be present in the measurement circuit. Suitable
A5
methods are (1) measuring the resistance with the current
B10
C25
flowing one direction through the test contact, reversing the
D50
current flow and remeasuring resistance, and averaging the two
E 100
resistance measurements; (2) measuring voltage drop across
F 200
G 400
the test contact with a constant d-c current flowing, measuring
H (number selected per agreement
voltage across the contact with no impressed current, and
between producer and user)
subtracting the second voltage from the first and using the
8.2 Sample Preparation:
8.2.1 Assemble the connectors into mounting plates, guides,
fixtures, racks, or similar apparatus if such apparatus is
generally used in the actual application of the connector.
Performsuchassemblyatthetimeinthesamplewiringprocess
that best simulates the typical manner in which the connectors
are assembled into a system.
8.2.2 Wire samples for evaluation by this test method for
electrical resistance measurements before the two connector
halves are plugged together. The wiring and resistance mea-
suring circuitry shall be of the four-wire type as described in
Test Methods B539. Do the wiring in a manner that is typical
of the way the connector would be wired in service, and
especially in a manner that does not introduce unrealistic
contaminants or mechanical stresses on the connector. Do not
perform cleaning, lubrication, or other treatments of the
connectorunlesssuchtreatmentsarespecifiedbytheconnector
manufacturer or user as the required procedure for the appli-
cation of the particular connector under test.
8.2.3 Wire at least one reference resistor for resistance
measurements in such a manner that its resistance may be
measuredusingthesameinstrumentationandproceduresasare
used for the test contacts. It is suggested that this reference
resistor be a length of wire or a path on a printed wiring board
with a resistance of the same order of magnitude as that of
typical test contacts. Measure and record the resistance of this
reference resistor each time that the test contacts are measured.
Expose this reference resistor to the same test environments as
the test contacts and generally treat the resistor in the same
manner as the test contacts.
8.2.4 Labeltheconnectorsandindividualcontactsthereinin
such a manner that each test contact is uniquely identified.
Randomly select one half of the connectors (10 connectors if
20 connectors is the total sample size) to undergo wear testing, FIG. 2 Sample Data Sheet
B794 − 97 (2009)
result to calculate resistance; or (3) measuring resistance using Provideaminimumdwelltimeof5sinboththeconnectedand
an a-c method. The user shall select one method and use it the unconnected position. Insertion and withdrawal velocity
throughout the experiment. shall be reasonably typical of that seen by the particular
8.3.4 Make all resistance measurements in such a manner connector in actual usage.
that the value is recorded with the resolution meeting the 8.4.5 Remeasure the resistance of each contact in the
following requirements: For contacts with a measured resis-
wear-test group and record the result as R4.After a value of R4
tance less than 0.100Ω, record the resistance with a resolution has been recorded for all contacts on a connector
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:B794–97(Reapproved2003) Designation:B794–97(Reapproved2009)
Standard Test Method for
Durability Wear Testing of Separable Electrical Connector
Systems Using Electrical Resistance Measurements
This standard is issued under the fixed designation B 794; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Thistestmethodcoverstheeffectsofrepeatedinsertionandwithdrawalofseparableelectricalconnectorswhichareharmful
to the electrical performance of the connector.
1.2 This test method is limited to electrical connectors designed for use in applications where the current through any one
connection in the connector does not exceed 5A, and where the connector may be separated a number of times during the life of
the connector.
1.3 This test method is limited to electrical connectors intended for use in air ambients where the operating temperature is less
than 65°C.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data
Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and
determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
B 539 Test Methods for Measuring Resistance of Electrical Connections (Static Contacts)Contacts)
2.2 Military Standard:
MIL-STD-1344A Test Methods for Electrical Connectors
3. Summary of Test Method
3.1 Sample connectors are wired for precision resistance measurements of each test contact. The samples are divided into two
groups; then resistance measurements are made of each test contact. The connectors in one group undergo a number of
insertion/withdrawalcyclesappropriatefortheparticularconnectorundertest,andtheresistancesoftheseconnectorsaremeasured
again. The connectors in the other group are not disturbed. All samples are subjected to an accelerated aging test; then the
resistances are measured again. All samples are separated (withdrawn), exposed to an accelerated aging test in the uninserted
condition, removed from the test, reinserted, and resistances measured again. The various resistance measurements are compared
to detect effects of the wear and aging on electrical performance.
4. Significance and Use
4.1 Materials for electrical connector contacts must satisfy a number of requirements in the areas of electrical, mechanical, and
economic characteristics.The stability of electrical properties is one of the most important of these characteristics.Wear of contact
surfaces may adversely affect these electrical properties, especially in designs where the contact surfaces are relatively thin
coatings. This test method provides a means to compare various material systems on a basis relevant to their application in
electrical connector contacts.
4.2 Repeated insertion and withdrawal of a connector may cause wear or other mechanical damage to the electrical contact
This test method is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on
Electrical Contact Test Methods.
Current edition approved June 10, 2003. Published July 2003. Originally approved in 1988. Last previous edition approved in 1997 as B794–97.
Current edition approved April 15, 2009. Published April 2009. Originally approved in 1988. Last previous edition approved in 2003 as B 794 – 97 (2003).
Annual Book of ASTM Standards, Vol 03.04.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.19111-5098,
http://www.dodssp.daps.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B794–97 (2009)
surfaces, rendering those surfaces more susceptible to environmental degradation. This test method is intended to detect
degradation of the electrical properties of the connector by such processes.
4.3 This test method describes procedures for conducting wear and durability testing of electrical connectors; the procedures
produce quantitative results. These results may be used to compare the performance of different connector designs so that
meaningful design choices can be made. Such results may also be used to compare the performance of a connector to a previously
established standard to evaluate the quality of the samples under test.
4.4 Thetestresultsobtainedfromthistestmethodarelimitedintheirapplicabilitytoconnectorcombinationsthatareequivalent
in design and manufacture to those actually tested.
4.5 The user is cautioned that the conditions in this test should be compared to the conditions that the connector will experience
in the intended application in order to determine the relevance of this test method to the particular needs of the user. For example,
the environmental stress in this test method is less severe than certain industrial and marine environments and therefore test results
are not directly applicable to predict the performance of product intended for use in such areas.
4.6 It is recommended that this test method be used in one of two ways. First, it may be used to evaluate and report the
performance of a particular connector system. In such a case, it is appropriate to report the results in a table in the format shown
in Fig. 1 and to state “ The results shown in the table were obtained for (insert connector designation or description) when tested
in accordance with ASTM Standard B 794, Method __ , Procedure __ .” Second, it may be used to impose requirements for
acceptance of product. In this case, limits for the values shown in Fig. 1 must be established prior to product acceptance testing.
Such limits may be established by various methods such as by evaluation of product which is known to be acceptable or by
application of appropriate experience. These limits must be documented in a manner that the entity performing the product test
can refer to the limits to determine if the test product conforms to such limits. A purchaser may wish to supply a table of limits
and include on the purchase order a statement similar to: “The product, when tested in accordance with ASTM Standard B 794,
Method __ , Procedure __ , shall meet the limits in the supplied table.” This table supplied by the purchaser may set limits on all
of the values in Fig. 1, or only on a subset of those values that the purchaser deems adequate to ensure the performance of the
product.
5. Apparatus
5.1 Environmental Test Chamber,capableofcontrollingthetestambientinaccordancewiththesequenceshowninTable1.The
test chamber shall be sufficiently large that each test sample shall be positioned with at least 100 mm separating it from the nearest
wall of the test chamber. The test chamber design and operation procedure shall conform to the requirements contained in
MIL-STD-1344A,, Method 1002.2.
5.2 An instrument is required for measuring resistance by the four-wire method. This instrument shall operate within the limits
on current and open-circuit voltage set forth in Test Methods B 539, Test Method C. The instrument shall be capable of measuring
FIG. 1 Sample Format for Reporting Results
B794–97 (2009)
TABLE 1 Environmental Test Sequence
NOTE 1—Tolerance on temperature control is 62°.
Step Elapsed Time, Temperature, Relative Humidity,
h °C %
1 0–2.5 ascending, 25–65 92 6 3
2 2.5–5.5 65 92 6 3
3 5.5–8 descending, 65–25 87 6 8
4 8–10.5 ascending, 25–65 92 6 3
5 10.5–13.5 65 92 6 3
6 13.5–16 descending, 65–25 87 6 8
7 16–24 25 92 6 3
a resistance less than 0.100 V with a resolution of 0.0001 V. For a resistance 0.100 V or larger, the instrument shall be capable
of measuring it with a resolution of 0.1 % of the resistance value.
6. Sampling and Test Specimens
6.1 Selection of Sample Connectors—Obtainsufficientsampleconnectorssothattheelectricalresistanceofatleast200contacts
contained in at least 20 separate connectors will be measured in the test. Obtain sample connectors that are representative of those
that will be used in the intended application. Recognize that a connector consists of two halves and both halves must be
representative of the product to be used. In some cases one half will be a conductive area or pad on a printed wiring-board surface,
therefore printed wiring boards must be obtained that have representative conductive pads. Specifically, the conductive pads shall
be manufactured to the same requirements as those that will be required of parts to be used in the system application. These
requirements will normally cover the manufacturing process, thickness, composition, hardness, and roughness of both the finish
coatingandofanyunderplatingorundercoating.Protectivetreatments,ifused,shallalsobespecified.Forthepurposeofconnector
testing, such printed wiring boards are generally fabricated with appropriate circuitry to permit four-wire resistance measurements.
6.2 Selection of Sample Contacts—In the case where the samples are multicontact connectors and electrical measurements are
performed only on a fraction of the total number of contacts, the contacts measured shall be distributed throughout the field of
contacts. Measure the corresponding contacts in each sample connector.
7. Conditioning
7.1 An electrical measurement laboratory is required in which the ambient temperature is controlled to 23 6 5°C and the
relative humidity is held below 60 %. This laboratory need not be dedicated to this test program to the exclusion of other uses so
long as those other uses do not degrade the quality of data obtained on the connector test samples.
8. Procedure
8.1 Selection of Test Method—Select a test method from the following table which is appropriate for connector design and
application.
Method Number of Insertions
A 5
B 10
C 25
D 50
E 100
F 200
G 400
H (number selected per agreement
between producer and user)
8.2 Sample Preparation:
8.2.1 Assemble the connectors into mounting plates, guides, fixtures, racks, or similar apparatus if such apparatus is generally
used in the actual application of the connector. Perform such assembly at the time in the sample wiring process that best simulates
the typical manner in which the connectors are assembled into a system.
8.2.2 Wire samples for evaluation by this test method for electrical resistance measurements before the two connector halves
are plugged together. The wiring and resistance measuring circuitry shall be of the four-wire type as described in Test Methods
B 539. Do the wiring in a manner that is typical of the way the connector would be wired in service, and especially in a manner
that does not introduce unrealistic contaminants or mechanical stresses on the connector. Do not perform cleaning, lubrication, or
other treatments of the connector unless such treatments are specified by the connector manufacturer or user as the required
procedure for the application of the particular connector under test.
8.2.3 Wireatleastonereferenceresistorforresistancemeasurementsinsuchamannerthatitsresistancemaybemeasuredusing
the same instrumentation and procedures as are used for the test contacts. It is suggested that this reference resistor be a length
ofwireorapathonaprintedwiringboardwitharesistanceofthesameorderofmagnitudeasthatoftypicaltestcontacts.Measure
B794–97 (2009)
and record the resistance of this reference resistor each time that the test contacts are measured. Expose this reference resistor to
the same test environments as the test contacts and generally treat the resistor in the same manner as the test contacts.
8.2.4 Label the connectors and individual contacts therein in such a manner that each test contact is uniquely identified.
Randomly select one half of the connectors (10 connectors if 20 connectors is the total sample size) to undergo wear testing, and
refer to these as the “wear test samples.” Insert the other half of the connectors only once at the beginning of the test and refer
to these as the “control samples.”
8.3 Methods and Procedures for Resistance Measurements:
8.3.1 Prepare data sheets such that all information shown in the sample data sheet illustrated in Fig. 2 may be recorded for each
test contact.
8.3.2 Perform all electrical measurements and wear tests in the electrical measurements laboratory discussed in Section 7. Test
samples must be allowed to come to equilibrium in this ambient for a minimum of 1 h before electrical measurements or connector
insertion/withdrawal operations begin. All connector insertion/withdrawal operations are done with the connector disconnected
from any power source.
8.3.3 Perform all resistance measurements under dry-circuit conditions as specified in Test Methods B 539, Test Method C. In
addition, use a suitable method to cancel small potentials that may be present in the measurement circuit. Suitable methods are
(1) measuring the resistance with the current flowing one direction through the test contact, reversing the current flow and
remeasuring resistance, and averaging the two resistance measurements; (2) measuring voltage drop across the test contact with
a constant d-c current flowing, measuring voltage across the contact with no impressed current, and subtracting the second voltage
from the first and using the result to calculate resistance; or (3) measuring resistance using an a-c method. The user shall select
one method and use it throughout the experiment.
8.3.4 Make all resistance measurements in such a manner that the value is recorded with the resolution meeting the following
requirements: For contacts with a measured resistance less than 0.100 V
...
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