ASTM B868-96(2008)

Standard Practice for Contact Performance Classification of Electrical Connection Systems

SIGNIFICANCE AND USE
This practice is based on the use of electrical resistance as an indicator of contact performance.
Existing standards, such as those referenced in Section 2 as representative examples, provide the basis for applied test conditions. Modifications in procedure or sample size, or both, of existing standards may have to be made to provide for resistance measurement and to meet variability index requirements that a user may specify.
This practice accommodates the use of multipletest methods, as may be required to assure satisfactory performance in a given application.
SCOPE
1.1 This practice provides a uniform method of specifying performance requirements for (or reporting test results of) electrical contact and connection systems. Both conductor and connector system performance may be specified by this practice, separately or in combination.
1.2 This practice may be used for separable or permanent contacts employing metallic conductors and contacts.
1.3 This practice provides methods for both signal and power applications.
1.4 This practice does not specify the sample preparation or test sequences required for determining contact performance. It is the responsibility of the user of this practice to determine the applied test sequence(s) appropriate for the application.
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.

General Information

• Status: Historical
• Publication Date: 29-Feb-2008
• ICS: 29.120.20 - Connecting devices
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.11 - Electrical Contact Test Methods

Relations

• Replaces: ASTM B868-96(2002)e3 - Standard Practice for Contact Performance Classification of Electrical Connection Systems
• Effective Date: 01-Mar-2008

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B868 −96(Reapproved 2008)
Standard Practice for
Contact Performance Classification of Electrical Connection
Systems
This standard is issued under the fixed designation B868; 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 B542Terminology Relating to Electrical Contacts andTheir
Use
1.1 This practice provides a uniform method of specifying
B812Test Method for Resistance to Environmental Degra-
performance requirements for (or reporting test results of)
dation of Electrical Pressure Connections Involving Alu-
electrical contact and connection systems. Both conductor and
minum and Intended for Residential Applications
connector system performance may be specified by this
2.2 UL Standard:
practice, separately or in combination.
UL 486B Wire Connectors for Use with Aluminum
1.2 This practice may be used for separable or permanent
Conductors, Third Edition, 1991
contacts employing metallic conductors and contacts.
3. Terminology
1.3 This practice provides methods for both signal and
power applications.
3.1 Terms used in this practice are defined in Terminology
B542 except as noted in 3.2.
1.4 This practice does not specify the sample preparation or
testsequencesrequiredfordeterminingcontactperformance.It
3.2 Definitions of Terms Specific to This Standard:
istheresponsibilityoftheuserofthispracticetodeterminethe
3.2.1 conductor, n—electrically conductive member carry-
applied test sequence(s) appropriate for the application.
ingcurrenttoacontactinterface.Examplesarewireandcable,
1.5 This standard does not purport to address all of the busbar, and conductive paths on an etched printed circuit
safety concerns, if any, associated with its use. It is the board.
responsibility of the user of this standard to become familiar
3.2.2 contact performance, n—contact interface behavior as
with all hazards including those identified in the appropriate
indicated by initial electrical resistance and resistance change
Material Safety Data Sheet (MSDS) for this product/material
under the applied test conditions.
as provided by the manufacturer, to establish appropriate
safety and health practices, and determine the applicability of
4. Summary of Practice
regulatory limitations prior to use.
4.1 The prescribed performance specification (or reporting)
statement consists of three sections, as follows:
2. Referenced Documents
4.1.1 Performance Classification, in accordance with this
2.1 ASTM Standards:
practice (Section 6).
B539Test Methods for Measuring Resistance of Electrical
4.1.2 Variability Index, determined by sample size and
Connections (Static Contacts)
distribution of resistance values measured at end of test, in
accordance with this practice (Section 7).
ThispracticeisunderthejurisdictionofASTMCommitteeB02onNonferrous
4.1.3 Statement of test method employed to determine
Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on
performance classification.
Electrical Contact Test Methods.
Current edition approved March 1, 2008. Published March 2008. Originally
4.2 The format for the performance specification (or report-
ε3
approved in 1996. Last previous edition approved in 2002 as B868–96(2002) .
ing) statement is as follows:
DOI: 10.1520/B0868-96R08.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from Underwriters Laboratories (UL), 333 Pfingsten Rd.,
the ASTM website. Northbrook, IL 60062-2096, http://www.ul.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B868−96 (2008)
6.2.3 For contacts incorporating or connecting conductors
of different materials or cross section, or both, the R value
d
used for contact performance determination shall be based on
the conductor of minimum resistance per unit length.
6.2.4 For contacts involving a connector, the conductor
material and cross section used for determination of the R
d
value to be used shall be the wire, busbar, circuit board
conductive strip, or other, as appropriate for the rating or
representative application of the connector.The conductor size
may be determined according to the connector manufacturer’s
specification, current rating, or conventional application prac-
5. Significance and Use
tice.
5.1 This practice is based on the use of electrical resistance
6.2.5 Conductor resistance per unit length is preferably
as an indicator of contact performance.
determined by measurements incorporating the same instru-
mentation used for contact resistance measurements, at the
5.2 Existingstandards,suchasthosereferencedinSection2
same ambient temperature and current as for the contact
as representative examples, provide the basis for applied test
performance test being applied.
conditions. Modifications in procedure or sample size, or both,
of existing standards may have to be made to provide for
6.2.6 When conductor resistance is determined at the same
resistance measurement and to meet variability index require-
time as contact performance in accordance with 6.2.5, and the
ments that a user may specify.
conductor is solid with circular cross section, potential drop
measurementsmaybeusedwithoutconversionforthepurpose
5.3 This practice accommodates the use of multiple test
of determining contact performance. (See example, Appendix
methods,asmayberequiredtoassuresatisfactoryperformance
X2.)
in a given application.
6.3 Contactresistanceshallbemeasuredinaccordancewith
6. Performance Classification
Test Methods B539.
6.1 The performance classification statement consists of
6.3.1 For power connections, resolution of resistance deter-
three letters in sequence indicating, respectively, category of
mination shall be 0.1 R or better. For most applications, this
d
contact (signal or power), average initial contact resistance,
requires potential drop resolution of 10 µV at a measurement
and change of average contact resistance as a consequence of
current density approximately equal to conductor ratings. (See
the applied test conditions.
Appendix X1.) Use Test Method B of Test Methods B539
6.2 Forthisstandardclassificationmethod,theperformance
adjusting the current to meet the stated current requirements.
of a connection system for power applications is expressed as
6.3.2 For signal connections, resolution of resistance deter-
theratioofthecontactresistancetotheequivalentresistanceof
mination shall be at 10% of the average initial contact
the attached conductor. The equivalent resistance of the con-
resistance or better, using Test Method C of Test Methods
ductor is the resistance of a length of solid circular conductor
B539.
exactlyonediameterinlength.Theconductorsizeusedforthe
6.3.3 For contact configurations in which bulk conductor or
evaluation shall be that which is normally specified or utilized
connector resistance is included in the measured contact
with the particular connection system being evaluated.
resistance, a single value of measured bulk resistance (seeTest
6.2.1 For connection systems involving solid circular
Methods B539) shall be subtracted from the measured contact
conductors, the equivalent resistance R is calculated accord-
d
resistance values. Resolution of the bulk resistance measure-
ing to the formula:
ment shall be 0.1 R or finer, and the bulk resistance measure-
d
R 5 R 3D
d
ment error tolerance shall be no greater than 60.2 R .
d
where:
6.4 The first letter of the performance classification, indi-
R = equivalent resistance,
d
cating contact category, shall be “P” for power contacts and
R = resistance per unit length, Ω, and
connections and “S” for signal contacts and connections. The
D = diameter of conductor (in same length unit).
letterisassignedaccordingtotheintendedapplicationforeach
6.2.1.1 Appendix X1 provides representative nominal data
of the applied test conditions.
forsomecommonsizesofcopperandaluminumconductorsof
6.4.1 A given connector type may be intended for multiple
circular cross section for the purpose of establishing instru-
applications, both signal and power (example: circuit board
mentation requirements.
connector). The category used for performance classification
6.2.2 For conductors with other than solid circular cross
for each test sequence applied shall be that for which the test
section, equivalent diameter based on actual conductive cross-
sequence is intended.
section area shall be used. For example: a conductor of
rectangular cross section 0.5 by 6 mm has a cross-section area 6.5 The letter indicating performance with respect to aver-
age (arithmetic mean) initial resistance of all samples tested
equaltothatofasolidcircularconductor1.95mmindiameter,
and therefore D in the equation in 6.2.1 is 1.95 mm. shall be in accordance with Table 1.
B868−96 (2008)
TABLE 1 Initial Resistance Indicator
where:
Initial Resistance Average Initial Resistance
R = resistance change for each connection tested, mΩ, and
c
Indicator
Power Category (P) Signal Category (S)
¯
A R <1.1 R R <5 mΩ
c d c = arithmetic mean resistance change for the total set of n
R
c
B<2 R <10 mΩ
d
connections tested, mΩ.
C<5 R <20 mΩ
d
D <10 R <50 mΩ
d
8. Format
E <100 R <100 mΩ
d
F <1000 R <200 mΩ
d
8.1 A format for specifying connection or contact perfor-
G $1000 R † $200 mΩ †
d
mance is: “Connections shall meet or exceed ASTM B868
ClassXXXwithYYvariabilityindexwhentestedaccordingto
† corrected editorially.
the applied conditions of ZZZ,” where “XXX” is the perfor-
mance classification (Section 6),“YY” is the variability index
6.6 The letter indicating performance with respect to resis-
(Section 7.1.1), and “ZZZ” is the specified test method. A
tance change of the worst-case sample tested shall be in
condensed form is: “Connections shall meet or exceedASTM
accordance with Table 2.
B868 Class XXX/YY/ZZZ.”
8.2 A format for reporting contact performance test results
TABLE 2 Resistance Change Indicator
is: “Performance is ASTM B868 XXX with YY variability
Power Category (P) Signal Category (S)
indexwhentestedaccordingtotheappliedconditionsofZZZ.”
Ratio: Final/I
...