ASTM B794-97(2020)

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: B794 − 97 (Reapproved 2020)
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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the effects of repeated insertion
B539 Test Methods for Measuring Resistance of Electrical
and withdrawal of separable electrical connectors which are
Connections (Static Contacts)
harmful to the electrical performance of the connector.
2.2 Military Standard:
1.2 This test method is limited to electrical connectors
MIL-STD-1344A Test Methods for Electrical Connectors
designed for use in applications where the current through any
3. Summary of Test Method
one connection in the connector does not exceed 5 A, and
where the connector may be separated a number of times
3.1 Sample connectors are wired for precision resistance
during the life of the connector.
measurements of each test contact. The samples are divided
into two groups; then resistance measurements are made of
1.3 This test method is limited to electrical connectors
each test contact. The connectors in one group undergo a
intended for use in air ambients where the operating tempera-
number of insertion/withdrawal cycles appropriate for the
ture is less than 65°C.
particular connector under test, and the resistances of these
1.4 The values stated in SI units are to be regarded as connectors are measured again. The connectors in the other
group are not disturbed. All samples are subjected to an
standard. No other units of measurement are included in this
accelerated aging test; then the resistances are measured again.
standard.
All samples are separated (withdrawn), exposed to an acceler-
1.5 This standard does not purport to address all of the
ated aging test in the uninserted condition, removed from the
safety concerns, if any, associated with its use. It is the
test, reinserted, and resistances measured again. The various
responsibility of the user of this standard to become familiar
resistance measurements are compared to detect effects of the
with all hazards including those identified in the appropriate
wear and aging on electrical performance.
Material Safety Data Sheet (MSDS) for this product/material
as provided by the manufacturer, to establish appropriate
4. Significance and Use
safety, health, and environmental practices, and determine the
4.1 Materials for electrical connector contacts must satisfy a
applicability of regulatory limitations prior to use.
number of requirements in the areas of electrical, mechanical,
1.6 This international standard was developed in accor-
and economic characteristics. The stability of electrical prop-
dance with internationally recognized principles on standard-
erties is one of the most important of these characteristics.
ization established in the Decision on Principles for the
Wear of contact surfaces may adversely affect these electrical
Development of International Standards, Guides and Recom- properties, especially in designs where the contact surfaces are
mendations issued by the World Trade Organization Technical relatively thin coatings. This test method provides a means to
Barriers to Trade (TBT) Committee. 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
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is under the jurisdiction of ASTM Committee B02 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee Standards volume information, refer to the standard’s Document Summary page on
B02.05 on Precious Metals and Electrical Contact Materials and Test Methods. the ASTM website.
Current edition approved Oct. 1, 2020. Published October 2020. Originally Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
approved in 1988. Last previous edition approved in 2015 as B794 – 97 (2015). Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
DOI: 10.1520/B0794-97R20. www.dodssp.daps.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B794 − 97 (2020)
contact surfaces, rendering those surfaces more susceptible to when tested in accordance with ASTM Standard B794,
environmental degradation. This test method is intended to Method __ , Procedure __ .” Second, it may be used to impose
detect degradation of the electrical properties of the connector requirements for acceptance of product. In this case, limits for
by such processes. the values shown in Fig. 1 must be established prior to product
acceptance testing. Such limits may be established by various
4.3 This test method describes procedures for conducting
methods such as by evaluation of product which is known to be
wear and durability testing of electrical connectors; the proce-
acceptable or by application of appropriate experience. These
dures produce quantitative results. These results may be used
limits must be documented in a manner that the entity
to compare the performance of different connector designs so
performing the product test can refer to the limits to determine
that meaningful design choices can be made. Such results may
if the test product conforms to such limits. A purchaser may
also be used to compare the performance of a connector to a
wish to supply a table of limits and include on the purchase
previously established standard to evaluate the quality of the
order a statement similar to: “The product, when tested in
samples under test.
accordance with ASTM Standard B794, Method __ , Proce-
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
4.5 The user is cautioned that the conditions in this test deems adequate to ensure the performance of the product.
should be compared to the conditions that the connector will
5. Apparatus
experience in the intended application in order to determine the
relevance of this test method to the particular needs of the user.
5.1 Environmental Test Chamber, capable of controlling the
For example, the environmental stress in this test method is
test ambient in accordance with the sequence shown in Table 1.
less severe than certain industrial and marine environments and
The test chamber shall be sufficiently large that each test
therefore test results are not directly applicable to predict the
sample shall be positioned with at least 100 mm separating it
performance of product intended for use in such areas.
from the nearest wall of the test chamber. The test chamber
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
performance of a particular connector system. In such a case,
5.2 An instrument is required for measuring resistance by
it is appropriate to report the results in a table in the format
the four-wire method. This instrument shall operate within the
shown in Fig. 1 and to state “The results shown in the table
limits on current and open-circuit voltage set forth in Test
were obtained for (insert connector designation or description)
Methods B539, Test Method C. The instrument shall be
capable of measuring a resistance less than 0.100 Ω with a
resolution of 0.0001 Ω. For a resistance 0.100 Ω 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—Obtain sufficient
sample connectors so that the electrical resistance of at least
200 contacts 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
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 (2020)
pads. Specifically, the conductive pads shall be manufactured measured using the same instrumentation and procedures as are
to the same requirements as those that will be required of parts used for the test contacts. It is suggested that this reference
to be used in the system application. These requirements will resistor be a length of wire or a path on a printed wiring board
normally cover the manufacturing process, thickness, with a resistance of the same order of magnitude as that of
composition, hardness, and roughness of both the finish coating typical test contacts. Measure and record the resistance of this
and of any underplating or undercoating. Protective treatments, reference resistor each time that the test contacts are measured.
if used, shall also be specified. For the purpose of connector Expose this reference resistor to the same test environments as
testing, such printed wiring boards are generally fabricated the test contacts and generally treat the resistor in the same
with appropriate circuitry to permit four-wire resistance mea- manner as the test contacts.
surements. 8.2.4 Label the connectors and individual contacts therein in
such a manner that each test contact is uniquely identified.
6.2 Selection of Sample Contacts—In the case where the
Randomly select one half of the connectors (10 connectors if
samples are multicontact connectors and electrical measure-
20 connectors is the total sample size) to undergo wear testing,
ments are performed only on a fraction of the total number of
and refer to these as the “wear test samples.” Insert the other
contacts, the contacts measured shall be distributed throughout
half of the connectors only once at the beginning of the test and
the field of contacts. Measure the corresponding contacts in
refer to these as the “control samples.”
each sample connector.
8.3 Methods and Procedures for Resistance Measurements:
7. Conditioning
8.3.1 Prepare data sheets such that all information shown in
the sample data sheet illustrated in Fig. 2 may be recorded for
7.1 An electrical measurement laboratory is required in
each test contact.
which the ambient temperature is controlled to 23 6 5°C and
8.3.2 Perform all electrical measurements and wear tests in
the relative humidity is held below 60 %. This laboratory need
the electrical measurements laboratory discussed in Section 7.
not be dedicated to this test program to the exclusion of other
Test samples must be allowed to come to equilibrium in this
uses so long as those other uses do not degrade the quality of
ambient for a minimum of 1 h before electrical measurements
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 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
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 FIG. 2 Sample Data Sheet
B794 − 97 (2020)
or connector insertion/withdrawal operations begin. All con- ments for each contact. If the absolute value of the difference
nector insertion/withdrawal operations are done with the con- between R1 and R2 exceeds 5 % of the sum of R1 and R2, then
nector disconnected from any power source. make and record a third measurement for that contact. Record
the new value as R3.
8.3.3 Perform all resistance measurements under dry-circuit
conditions as specified in Test Methods B539, Test Method C. 8.4.3 Disconnect the test contacts from any power source
during the connector withdrawal/insertion operations.
In addition, use a suitable method to cancel small potentials
that may be present in the measurement circuit. Suitable
8.4.4 Using any guides, handles, levers, or other mechanical
methods are (1) measuring the resistance with the current
aides provided by the connector and its housing, repeatedly
flowing one direction through the test contac
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