ASTM B868-96(2002)e2
(Practice)Standard Practice for Contact Performance Classification of Electrical Connection Systems
Standard Practice for Contact Performance Classification of Electrical Connection Systems
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 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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e2
Designation: B 868 – 96 (Reapproved 2002)
Standard Practice for
Contact Performance Classification of Electrical Connection
Systems
This standard is issued under the fixed designation B 868; 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.
e NOTE—Paragraph 1.5 was corrected editorially in June 2002.
e NOTE—Editorial changes were made throughout in March 2005.
1. Scope radation of Electrical Pressure Connections Involving
Aluminum and Intended for Residential Applications
1.1 This practice provides a uniform method of specifying
2.2 UL Standard:
performance requirements for (or reporting test results of)
UL 486B Wire Connectors for Use with Aluminum Con-
electrical contact and connection systems. Both conductor and
ductors, Third Edition, 1991
connector system performance may be specified by this prac-
2.3 EEI-NEMA Standard:
tice, separately or in combination.
EEI-NEMA Standard TDJ-162 (ANSI C119.4), “Connec-
1.2 This practice may be used for separable or permanent
tors for Use Between Aluminum-to-Aluminum or
contacts employing metallic conductors and contacts.
Aluminum-to-Copper Bare Overhead Conductors”
1.3 This practice provides methods for both signal and
power applications.
3. Terminology
1.4 This practice does not specify the sample preparation or
3.1 Terms used in this practice are defined in Terminology
testsequencesrequiredfordeterminingcontactperformance.It
B 542 except as noted in 3.2.
is the responsibility of the user of this practice to determine the
3.2 Definitions of Terms Specific to This Standard:
applied test sequence(s) appropriate for the application.
3.2.1 conductor, n—electrically conductive member carry-
1.5 This standard does not purport to address all of the
ing current to a contact interface. Examples are wire and cable,
safety concerns, if any, associated with its use. It is the
busbar, and conductive paths on an etched printed circuit
responsibility of the user of this standard to become familiar
board.
with all hazards including those identified in the appropriate
3.2.2 contact performance, n—contact interface behavior as
Material Safety Data Sheet for this product/material as pro-
indicated by initial electrical resistance and resistance change
vided by the manufacturer, to establish appropriate safety and
under the applied test conditions.
health practices, and determine the applicability of regulatory
limitations prior to use.
4. Summary of Practice
2. Referenced Documents 4.1 The prescribed performance specification (or reporting)
2 statement consists of three sections, as follows:
2.1 ASTM Standards:
4.1.1 Performance Classification, in accordance with this
B 539 Test Methods for Measuring Resistance of Electrical
practice (Section 6).
Connections (Static Contacts)
4.1.2 Variability Index, determined by sample size and
B 542 Terminology Relating to Electrical Contacts and
distribution of resistance values measured at end of test, in
Their Use
accordance with this practice (Section 7).
B 812 Test Method for Resistance to Environmental Deg-
4.1.3 Statement of test method employed to determine
performance classification.
1 4.2 The format for the performance specification (or report-
This practice is under the jurisdiction ofASTM Committee B02 on Nonferrous
Metals and Alloys and is the direct responsibility of Subcommittee B02.11 on ing) statement is as follows:
Electrical Contact Test Methods.
Current edition approved March 10, 1996. Published May 1996.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Underwriters Laboratories (UL), Corporate Progress, 333
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Pfingsten Rd., Northbrook, IL 60062.
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
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B 868 – 96 (2002)
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-
tice.
5. Significance and Use 6.2.5 Conductor resistance per unit length is preferably
determined by measurements incorporating the same instru-
5.1 This practice is based on the use of electrical resistance
mentation used for contact resistance measurements, at the
as an indicator of contact performance.
same ambient temperature and current as for the contact
5.2 Existingstandards,suchasthosereferencedinSection2
performance test being applied.
as representative examples, provide the basis for applied test
6.2.6 When conductor resistance is determined at the same
conditions. Modifications in procedure or sample size, or both,
time as contact performance in accordance with 6.2.5, and the
of existing standards may have to be made to provide for
conductor is solid with circular cross section, potential drop
resistance measurement and to meet variability index require-
measurements may be used without conversion for the purpose
ments that a user may specify.
of determining contact performance. (See example, Appendix
5.3 This practice accommodates the use of multiple test
X2.)
methods,asmayberequiredtoassuresatisfactoryperformance
6.3 Contact resistance shall be measured in accordance with
in a given application.
Test Methods B 539.
6.3.1 For power connections, resolution of resistance deter-
6. Performance Classification
mination shall be 0.1 R or better. For most applications, this
d
6.1 The performance classification statement consists of
requires potential drop resolution of 10 µV at a measurement
three letters in sequence indicating, respectively, category of
current density approximately equal to conductor ratings. (See
contact (signal or power), average initial contact resistance,
Appendix X1.) Use Test Method B of Test Methods B 539
and change of average contact resistance as a consequence of
adjusting the current to meet the stated current requirements.
the applied test conditions.
6.3.2 For signal connections, resolution of resistance deter-
6.2 For this standard classification method, the performance
mination shall be at 10 % of the average initial contact
of a connection system for power applications is expressed as
resistance or better, using Test Method C of Test Methods
theratioofthecontactresistancetotheequivalentresistanceof
B 539.
the attached conductor. The equivalent resistance of the con-
6.3.3 For contact configurations in which bulk conductor or
ductor is the resistance of a length of solid circular conductor
connector resistance is included in the measured contact
exactly one diameter in length.The conductor size used for the
resistance, a single value of measured bulk resistance (see Test
evaluation shall be that which is normally specified or utilized
Methods B 539) shall be subtracted from the measured contact
with the particular connection system being evaluated.
resistance values. Resolution of the bulk resistance measure-
6.2.1 For connection systems involving solid circular con-
ment shall be 0.1 R or finer, and the bulk resistance measure-
d
ductors, the equivalent resistance R is calculated according to
d
ment error tolerance shall be no greater than 60.2 R .
d
the formula:
6.4 The first letter of the performance classification, indi-
R 5 R 3 D
d
cating contact category, shall be “P” for power contacts and
connections and “S” for signal contacts and connections. The
where:
letter is assigned according to the intended application for each
R = equivalent resistance,
d
of the applied test conditions.
R = resistance per unit length, V, and
D = diameter of conductor (in same length unit). 6.4.1 A given connector type may be intended for multiple
applications, both signal and power (example: circuit board
6.2.1.1 Appendix X1 provides representative nominal data
connector). The category used for performance classification
for some common sizes of copper and aluminum conductors of
for each test sequence applied shall be that for which the test
circular cross section for the purpose of establishing instru-
sequence is intended.
mentation requirements.
6.5 The letter indicating performance with respect to aver-
6.2.2 For conductors with other than solid circular cross
age (arithmetic mean) initial resistance of all samples tested
section, equivalent diameter based on actual conductive cross-
shall be in accordance with Table 1.
section area shall be used. For example: a conductor of
rectangular cross section 0.5 by 6 mm has a cross-section area 6.6 The letter indicating performance with respect to resis-
equal to that of a solid circular conductor 1.95 mm in diameter, tance change of the worst-case sample tested shall be in
and therefore D in the equation in 6.2.1 is 1.95 mm. accordance with Table 2.
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B 868 – 96 (2002)
TABLE 1 Initial Resistance Indicator
R = arithmetic mean resistance change for the total set of
c
Initial Resistance Average Initial Resistance
n connections tested, mV.
Indicator
Power Category (P) Signal Category (S)
8. Format
A R <1.1 R R <5mV
c d c
B<2 R <10 mV
d 8.1 A format for specifying connection or contact perfor-
C<5 R <20 mV
d
mance is: “Connections shall meet or exceed ASTM B 868
D <10 R <50 mV
d
Class XXX withYYvariability index when tested according to
E <100 R <100 mV
d
F <1000 R <200 mV
d the applied conditions of ZZZ,” where “XXX” is the perfor-
G >1000 R >200 mV
d
mance classification (Section 6),“YY” is the variability index
(Section 7.1.1), and “ZZZ” is the specified test method. A
condensed form is: “Connections shall meet or exceed ASTM
TABLE 2 Resistance Change Indicator
B 868 Class XXX/YY/ZZZ.”
Power Category (P) Signal Cat
...
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