ASTM B794-97
(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
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 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: B 794 – 97
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope All samples are separated (withdrawn), exposed to an acceler-
ated aging test in the uninserted condition, removed from the
1.1 This test method covers the effects of repeated insertion
test, reinserted, and resistances measured again. The various
and withdrawal of separable electrical connectors which are
resistance measurements are compared to detect effects of the
harmful to the electrical performance of the connector.
wear and aging on electrical performance.
1.2 This test method is limited to electrical connectors
designed for use in applications where the current through any
4. Significance and Use
one connection in the connector does not exceed 5 A, and
4.1 Materials for electrical connector contacts must satisfy a
where the connector may be separated a number of times
number of requirements in the areas of electrical, mechanical,
during the life of the connector.
and economic characteristics. The stability of electrical prop-
1.3 This test method is limited to electrical connectors
erties is one of the most important of these characteristics.
intended for use in air ambients where the operating tempera-
Wear of contact surfaces may adversely affect these electrical
ture is less than 65°C.
properties, especially in designs where the contact surfaces are
1.4 This standard does not purport to address all of the
relatively thin coatings. This test method provides a means to
safety concerns, if any, associated with its use. It is the
compare various material systems on a basis relevant to their
responsibility of the user of this standard to establish appro-
application in electrical connector contacts.
priate safety and health practices and determine the applica-
4.2 Repeated insertion and withdrawal of a connector may
bility of regulatory limitations prior to use.
cause wear or other mechanical damage to the electrical
2. Referenced Documents contact surfaces, rendering those surfaces more susceptible to
environmental degradation. This test method is intended to
2.1 ASTM Standards:
detect degradation of the electrical properties of the connector
B 539 Test Methods for Measuring Contact Resistance of
by such processes.
Electrical Connections (Static Contacts)
4.3 This test method describes procedures for conducting
2.2 Military Standard:
wear and durability testing of electrical connectors; the proce-
MIL-STD-1344A Test Methods for Electrical Connectors
dures produce quantitative results. These results may be used
3. Summary of Test Method
to compare the performance of different connector designs so
that meaningful design choices can be made. Such results may
3.1 Sample connectors are wired for precision resistance
also be used to compare the performance of a connector to a
measurements of each test contact. The samples are divided
previously established standard to evaluate the quality of the
into two groups; then resistance measurements are made of
samples under test.
each test contact. The connectors in one group undergo a
4.4 The test results obtained from this test method are
number of insertion/withdrawal cycles appropriate for the
limited in their applicability to connector combinations that are
particular connector under test, and the resistances of these
equivalent in design and manufacture to those actually tested.
connectors are measured again. The connectors in the other
4.5 The user is cautioned that the conditions in this test
group are not disturbed. All samples are subjected to an
should be compared to the conditions that the connector will
accelerated aging test; then the resistances are measured again.
experience in the intended application in order to determine the
relevance of this test method to the particular needs of the user.
This test method is under the jurisdiction of ASTM Committee B-2 on
For example, the environmental stress in this test method is
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
less severe than certain industrial and marine environments and
B02.11 on Electrical Contact Test Methods.
Current edition approved Dec. 10, 1997. Published October 1998. Originally
therefore test results are not directly applicable to predict the
published as B 794 – 88. Last previous edition B 794 – 93
performance of product intended for use in such areas.
Annual Book of ASTM Standards, Vol 03.04.
3 4.6 It is recommended that this test method be used in one
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
of two ways. First, it may be used to evaluate and report the
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
B 794
TABLE 1 Environmental Test Sequence
performance of a particular connector system. In such a case,
it is appropriate to report the results in a table in the format
NOTE 1—Tolerance on temperature control is 62°.
shown in Fig. 1 and to state“ The results shown in the table
were obtained for (insert connector designation or description)
Step Elapsed Time, Temperature, Relative Humidity,
h °C %
when tested in accordance with ASTM Standard B 794,
Method __ , Procedure __ .’’ Second, it may be used to impose 1 0–2.5 ascending, 25–65 92 6 3
2 2.5–5.5 65 92 6 3
requirements for acceptance of product. In this case, limits for
3 5.5–8 descending, 65–25 87 6 8
the values shown in Fig. 1 must be established prior to product
4 8–10.5 ascending, 25–65 92 6 3
5 10.5–13.5 65 92 6 3
acceptance testing. Such limits may be established by various
6 13.5–16 descending, 65–25 87 6 8
methods such as by evaluation of product which is known to be
7 16–24 25 92 6 3
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
limits on current and open-circuit voltage set forth in Test
if the test product conforms to such limits. A purchaser may
Methods B 539, Test Method C. The instrument shall be
wish to supply a table of limits and include on the purchase
capable of measuring a resistance less than 0.100 V with a
order a statement similar to: “The product, when tested in
resolution of 0.0001 V. For a resistance 0.100 V or larger, the
accordance with ASTM Standard B 794, Method __ , Proce-
instrument shall be capable of measuring it with a resolution of
dure __ , shall meet the limits in the supplied table.’’ This table
0.1 % of the resistance value.
supplied by the purchaser may set limits on all of the values in
6. Sampling and Test Specimens
Fig. 1, or only on a subset of those values that the purchaser
deems adequate to ensure the performance of the product.
6.1 Selection of Sample Connectors—Obtain sufficient
sample connectors so that the electrical resistance of at least
5. Apparatus
200 contacts contained in at least 20 separate connectors will
5.1 Environmental Test Chamber, capable of controlling the
be measured in the test. Obtain sample connectors that are
test ambient in accordance with the sequence shown in Table 1.
representative of those that will be used in the intended
The test chamber shall be sufficiently large that each test
application. Recognize that a connector consists of two halves
sample shall be positioned with at least 100 mm separating it
and both halves must be representative of the product to be
from the nearest wall of the test chamber. The test chamber
used. In some cases one half will be a conductive area or pad
design and operation procedure shall conform to the require-
on a printed wiring-board surface, therefore printed wiring
ments contained in MIL-STD-1344A, Method 1002.2.
boards must be obtained that have representative conductive
5.2 An instrument is required for measuring resistance by
pads. Specifically, the conductive pads shall be manufactured
the four-wire method. This instrument shall operate within the
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, compo-
sition, hardness, and roughness of both the finish coating 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
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
FIG. 1 Sample Format for Reporting Results application.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
B 794
Method Number of Insertions
A5
B10
C25
D50
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 mea-
suring 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 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
measured using the same instrumentation and procedures as are
used for the test contacts. It is suggested that this reference
FIG. 2 Sample Data Sheet
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
In addition, use a suitable method to cancel small potentials
reference resistor each time that the test contacts are measured.
that may be present in the measurement circuit. Suitable
Expose this reference resistor to the same test environments as
methods are (1) measuring the resistance with the current
the test contacts and generally treat the resistor in the same
flowing one direction through the test contact, reversing the
manner as the test contacts.
current flow and remeasuring resistance, and averaging the two
8.2.4 Label the connectors and individual contacts therein in
resistance measurements; (2) measuring voltage drop across
such a manner that each test contact is uniquely identified.
the test contact with a constant d-c current flowing, measuring
Randomly select one half of the connectors (10 connectors if
voltage across the contact with no impressed current, and
20 connectors is the total sample size) to undergo wear testing,
subtracting the second voltage from the first and using the
and refer to these as the“ wear test samples.’’ Insert the other
result to calculate resistance; or (3) measuring resistance using
half of the connectors only once at the beginning of the test and
an a-c method. The user shall select one method and use it
refer to these as the “control samples.’’
throughout the experiment.
8.3 Methods and Procedures for Resistance Measurements:
8.3.4 Make all resistance measurements in such a manner
8.3.1 Prepare data sheets such that all information shown in
that the value is recorded with the resolution meeting the
the sample data sheet illustrated in Fig. 2 may be recorded for
following requirements: For contacts with a measured resis-
each test contact.
tance less than 0.100 V, record the resistance with a resolution
8.3.2 Perform all electrical measurements and wear tests in of 0.0001 V or better. For contacts with resistance of 0.100 V
the electrical measurements laboratory discussed in Section 7. or greater, record the resistance measurement with a resolution
Test samples must be allowed to come to equilibrium in this of 0.1 % or better. If the resistance changes during the
ambient for a minimum of 1 h before electrical measurements
measurement such that after about5sa stable value of the
or connector insertion/withdrawal operations begin. All con- required resolution cannot be determined, record an estimate
nector insertion/withdrawal operations are done with the con-
and note that the resistance is unstable.
nector disconnected from any power source.
8.3.5 After each measurement of the reference resistor,
8.3.3 Perform all resistance measurements under dry-circuit compare the new measured value to the initial value. If the
conditions as specified in Test Methods B 539, Test Method C. values differ by more than 2 %, check the calibration of the
NOTICE: T
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