ASTM B539-01
(Test Method)Standard Test Methods for Measuring Resistance of Electrical Connections (Static Contacts)
Standard Test Methods for Measuring Resistance of Electrical Connections (Static Contacts)
SCOPE
1.1 These test methods cover equipment and techniques for measuring the resistance of static electrical connections such as wire terminations or splices, friction connectors, soldered joints, and wrapped-wire connections.
1.2 Measurements under two distinct levels of electrical loading are described. These levels are: (1) dry circuit, (2) and rated current. One or both of these levels of loading may be required in specific cases.
1.3 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 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.4 It is the responsibility of the user 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.
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Standards Content (Sample)
An American National Standard
Designation: B 539 – 01
Standard Test Methods for
Measuring Resistance of Electrical Connections (Static
1
Contacts)
This standard is issued under the fixed designation B 539; 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 3.1.2 connection resistance—the resistance from the termi-
nation point on one end of a device containing static contacts,
1.1 These test methods cover equipment and techniques for
through the contacts to the termination point on the other end
measuring the resistance of static electrical connections such as
of the device. The termination point is the location on a
wire terminations or splices, friction connectors, soldered
terminal of a device where a wire or printed circuit path
joints, and wrapped-wire connections.
electrically connects to the terminal. This resistance is the
1.2 Measurements under two distinct levels of electrical
value of resistance displayed by the device in a circuit
loading are described. These levels are: (1) dry circuit, (2) and
application.
rated current. One or both of these levels of loading may be
3.1.2.1 Discussion—The term contact resistance is often
required in specific cases.
used in commercial literature to indicate the connection resis-
1.3 This standard does not purport to address all of the
tance displayed by the device in a standard application. In the
safety concerns, if any, associated with its use. It is the
more rigorous usage of contact resistance, the connection
responsibility of the user of this standard to establish appro-
resistance is the sum of the contact resistance plus the bulk
priate safety and health practices and determine the applica-
resistance of leads within the device that go to the static
bility of regulatory limitations prior to use.
contacts from the point that the leads are connected to the
1.4 It is the responsibility of the user to become familiar
external circuitry. Measurement of contact resistance indepen-
with all hazards including those identified in the appropriate
dent of all bulk resistance is very difficult for most commercial
Material Safety Data Sheet for this product/material as pro-
devices.
vided by the manufacturer.
3.1.3 dry circuit—a circuit in which the open-circuit voltage
2. Referenced Documents is less than or equal to 20 mV. Current is usually low in a dry
circuit, but a low-current circuit is not necessarily a dry circuit.
2.1 ASTM Standards:
When the applied voltage (open-circuit voltage) is too low to
B 542 Terminology Relating to Electrical Contacts and
2
cause any physical changes in the contact junction, such as
Their Use
break-down of thin insulating films or softening of contact
E 122 Practice for Calculating Sample Size to Estimate,
asperities, the circuit is said to be a dry circuit.
With a Specified Tolerable Error, the Average for a
3
3.1.4 open-circuit voltage—the steady-state voltage which
Characteristic of a Lot or Process
would appear across the contacts if they were opened.
3. Terminology
3.1.5 static contacts—electric junctions designed for infre-
quent separation and connection, and intended to perform their
3.1 Definitions: see Terminology B 542 for definitions of
function only when contacting members are stationary relative
contact resistance, film resistance, and constriction resistance.
to each other. This definition includes crimped, welded, brazed,
3.1.1 bulk resistance—the resistance a contact assembly
riveted, or soldered joints; friction connections such as pin and
would have if it were solid metal of an identical geometry so
socket connectors or taper pins, twisted-wire splices; and
that the nominal contact area offered zero resistance. When
connections made with screws, or bolts and nuts between
measuring contact resistance one attempts to include as little
electrical wiring and components. The definition excludes
bulk resistance as possible in the measurement, by placing
relay contacts, slip rings and commutators, and switches and
measuring probes as close to the contact interface as practical.
circuit breakers.
3.2 Descriptions of Terms for Levels of Electrical Loading:
1
These test methods are under the jurisdiction of ASTM Committee B02 on
3.2.1 dry circuit—This method provides for measurement
Nonferrous Metals and Alloys and are the direct responsibility of Subcommittee
of contact resistance under very low levels of electrical
B02.11 on Electrical Contact Test Methods.
Current edition approved Nov. 10, 2001. Published January 2002. Originally
excitation, with applied voltages and currents selected to be too
published as B 539 – 70. Last previous edition B 539 – 96.
low to cause breakdown of thin oxide films or other contami-
2
Annual Book of ASTM Standards, Vol 02.04.
3 nates in the con
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