ASTM B812-96(2002)e1
(Test Method)Standard Test Method for Resistance to Environmental Degradation of Electrical Pressure Connections Involving Aluminum and Intended for Residential Applications
Standard Test Method for Resistance to Environmental Degradation of Electrical Pressure Connections Involving Aluminum and Intended for Residential Applications
SCOPE
1.1 This test method covers all residential pressure connection systems. Detailed examples of application to specific types of connection systems, set-screw neutral bus connectors and twist-on wire-splicing connectors, are provided in Appendix X1 and Appendix X2.
1.2 The purpose of this test method is to evaluate the performance of residential electrical pressure connection systems under conditions of cyclic temperature change (within rating) and high humidity.
1.3 The limitations of the test method are as follows:
1.3.1 This test method shall not be considered to confirm a specific lifetime in application environments.
1.3.2 The applicability of this test method is limited to pressure connection systems rated at or below 600 V d-c or a-c RMS.
1.3.3 This test method is limited to temperature and water vapor exposure in addition to electrical current as required to measure connection resistance.
1.3.4 This test method does not evaluate degradation which may occur in residential applications due to exposure of the electrical connection system to additional environmental constituents such as (but not limited to) the following examples:
1.3.4.1 Household chemicals (liquid or gaseous) such as ammonia, bleach, or other cleaning agents.
1.3.4.2 Chemicals as may occur due to normal hobby or professional activities such as photography, painting, sculpture, or similar activities.
1.3.4.3 Environments encountered during construction or remodeling such as direct exposure to rain, uncured wet concrete, welding or soldering fluxes and other agents.
1.3.5 This test method is limited to evaluation of pressure connection systems.
1.4 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./p>
1.4 This standard should be used to measure and describe the properties of materials, products, or assemblies in response to electrical current flow under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual installation conditions or under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use.
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e1
Designation:B812–96(Reapproved2002)
Standard Test Method for
Resistance to Environmental Degradation of Electrical
Pressure Connections Involving Aluminum and Intended for
Residential Applications
This standard is issued under the fixed designation B 812; 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 1.4 was corrected editorially in June 2002.
INTRODUCTION
Electrical pressure connection systems involving aluminum are those in which one or more of the
components of the system in the direct electrical path or carrying any electrical current is fabricated
ofaluminum,includingaluminumwires,aluminumbusbars,aluminumbolts,aluminumterminations,
or any other aluminum current-carrying member. Included are systems which must carry current for
safety purposes such as ground shields or straps attached to aluminum framing or other structural
members. Pressure connection systems can be evaluated by this test method. Such systems are
comprised of the wire or other structure being connected and the means of connection, any element
of which is made of aluminum.
Connection systems tested are exposed sequentially to ambients of high relative humidity and
temperature cycles of 75°C, such as may be encountered by some connections in actual residential
applications.Periodicobservationofthepotentialdropacrosstheconnectioninterfaceswhilecarrying
rated current provides a measurement of connection performance.
1. Scope 1.3.3 This test method is limited to temperature and water
vapor exposure in addition to electrical current as required to
1.1 This test method covers all residential pressure connec-
measure connection resistance.
tionsystems.Detailedexamplesofapplicationtospecifictypes
1.3.4 This test method does not evaluate degradation which
of connection systems, set-screw neutral bus connectors and
may occur in residential applications due to exposure of the
twist-on wire-splicing connectors, are provided in Appendix
electrical connection system to additional environmental con-
X1 and Appendix X2.
stituents such as (but not limited to) the following examples:
1.2 The purpose of this test method is to evaluate the
1.3.4.1 Household chemicals (liquid or gaseous) such as
performance of residential electrical pressure connection sys-
ammonia, bleach, or other cleaning agents.
tems under conditions of cyclic temperature change (within
1.3.4.2 Chemicals as may occur due to normal hobby or
rating) and high humidity.
professionalactivitiessuchasphotography,painting,sculpture,
1.3 The limitations of the test method are as follows:
or similar activities.
1.3.1 This test method shall not be considered to confirm a
1.3.4.3 Environments encountered during construction or
specific lifetime in application environments.
remodeling such as direct exposure to rain, uncured wet
1.3.2 The applicability of this test method is limited to
concrete, welding or soldering fluxes and other agents.
pressure connection systems rated at or below 600Vd-c or a-c
1.3.5 This test method is limited to evaluation of pressure
RMS.
connection systems.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
This test method is under the jurisdiction of ASTM Committee B02 on
responsibility of the user of this standard to become familiar
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
with all hazards including those identified in the appropriate
B02.11 on Electrical Contact Test Methods.
Material Safety Data Sheet for this product/material as pro-
Current edition approved May 10, 1996. Published July 1996. Originally
published as B 812 – 90. Last previous edition B 812 – 90. vided by the manufacturer, to establish appropriate safety and
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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B812–96 (2002)
health practices, and determine the applicability of regulatory the connection system being tested by being mounted on the
limitations prior to use. same test board assembly and connected in the same series
1.5 This standard should be used to measure and describe circuit.
the properties of materials, products, or assemblies in response 3.5 reference connection system—the reference connection
to electrical current flow under controlled laboratory condi- system is the same connection system as that which is under
tions and should not be used to describe or appraise the fire evaluation, but which is exposed only to a dry environment at
hazard or fire risk of materials, products, or assemblies under normal room temperature.
actual installation conditions or under actual fire conditions.
4. Summary of Test Method
However, results of this test may be used as elements of a fire
4.1 The environmental exposure of the connections tested
risk assessment which takes into account all of the factors
consists of weekly sequences consisting of five thermal cycles
which are pertinent to an assessment of the fire hazard of a
of 75°C temperature change (taking a maximum of8hto
particular end use.
accomplish), followed by exposure for the balance of the week
to conditions at or near 100 % relative humidity at room
2. Referenced Documents
temperature. The text exposure cycle is repeated for a mini-
2.1 ASTM Standards:
mum of four one-week cycles. Reference connections are kept
B 542 Terminology Relating to Electrical Contacts and
in a dry environment at room temperature for the same
Their Use
duration. Potential drop measurements, at rated current, are
2.2 Underwriter Laboratory Standards
made prior to each weekly environmental exposure cycle, and
UL486B, Standard for Wire Connectors For Use With
a final set of measurements is taken at the end of the test.
Aluminum Conductors, ANSI/UL 486B
UL486C, Standard for Splicing Wire Connectors
5. Significance and Use
2.3 National Electrical Code:
5.1 The principal underlying the test is the sensitivity of the
ANSI/NFPA 70
electricalcontactinterfacetotemperatureandhumiditycycling
that electrical pressure connection systems experience as a
3. Terminology
result of usage and installation environment. The temperature
cyclingmaycausemicromotionatthematingelectricalcontact
3.1 residential applications—residential applications are
surfaces which can expose fresh metal to the local ambient
those involving a structure or vehicle used entirely for perma-
atmosphere. The humidity exposure is known to facilitate
nent or temporary human habitation. Included are homes
corrosion on freshly exposed metal surfaces. Thus, for those
(single or multiple-unit houses and mobile or modular struc-
connection systems that do not maintain stable metal-to-metal
tures), motels, hotels, dormitories, hospitals, rest homes, and
contact surfaces under the condition of thermal cycling and
recreational vehicles. Excluded are railroad cars, boats, air-
humidity exposure, repeated sequences of these exposures lead
planes, nonresidential, commercial (office buildings, stores)
to degradation of the contacting surface indicated by potential
and industrial applications (factories, warehouses).
drop increase.
3.2 pressure connection system—an electrical connection
5.2 The test is of short duration relative to the expected life
intended to carry current between components or conductors in
of connections in residential usage. Stability of connection
contact under mechanical pressure.
resistance implies resistance to deterioration due to environ-
3.2.1 Discussion—The mechanical pressure may be applied
mental conditions encountered in residential service. Increas-
by clamping, tightening of threaded components, spring force,
ing connection resistance as a result of the test exposure
crimping, swaging, or other means. For the purpose of the test
indicates deterioration of electrical contact interfaces. Assur-
procedure, the connection system consists of all components
anceoflongtermreliabilityandsafetyofconnectiontypesthat
normally present in the application, including both current-
deteriorate requires further evaluation for specific specified
carrying and other metallic components, and non-metallic
environments and applications.
components (insulators, insulation, protective boots or sleeve,
5.3 Use—Itisrecommendedthatthistestmethodbeusedin
etc.). Also see definition of “Connection, Pressure (Solder-
one of two ways. First, it may be used to evaluate and report
less),” in Article 100 of reference noted in Section 2.3 (NEC).
the performance of a particular connection system. For such
3.3 aluminum—as the term “aluminum,” the material of
use, it is appropriate to report the results in a summary (or
which conductors (wire, cable, busbars, etc.), connection
tabular) format such as shown in Section 17, together with the
components,andtestboardcomponentsmaybemade,includes
statement “ The results shown in the summary (or table) were
aluminum metal and its alloys.
obtained for (insert description of connection) when tested in
3.4 reference conductor—a continuous length of the same
accordance withTest Method B 812. Second, it may be used as
conductor material (wire, cable, busbar, etc.) incorporated in
the basis for specification of acceptability of product. For this
use, the minimum test time and the maximum allowable
increase in potential drop must be established by the specifier.
Annual Book of ASTM Standards, Vol 02.04.
Specificationofconnectionsystemsinaccordancewiththisuse
Available from Underwriters Laboratories, 333 Pfingsten Rd., Northbrook, IL
of the standard test method would be of the form: “The
60062–2096.
maximum potential drop increase for any connection, when
National Fire Protection Association, 1 Batterymarch Park, Quincy, MA
02269–9101. tested in accordance with Test Method B 812 for a period of
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B812–96 (2002)
weeks, shall be mV relative to the reference connections.” such that no contamination of test samples or deionized water
Connection systems that are most resistant to thermal-cycle/ occurs. The vessel is to be operated in a normal laboratory
humidity deterioration, within the limitations of determination environment which has continuous temperature control during
bythistestmethod,shownoincreaseinpotentialdrop,relative the period of the test.
to the reference connections, when tested for indefinite time.
NOTE 1—This apparatus is intended to expose samples to relative
Connections that are less resistant to thermal-cycle/humidity
humidity at or near 100 %.
conditions applied by this test will demonstrate progressive
7.3 Temperature Chamber—The temperature chamber shall
increases in potential drop with increasing time on test. Thus,
be capable of control at the defined upper temperature of the
the following examples of specifications are in the order of
thermal cycle such that chamber temperature stability, unifor-
most stringent (No. 1) to least stringent (No. 3).
mity, and control accuracy shall be within 62°C. The lower
Duration, weeks Maximum Potential Drop Increase, mV
temperatureofthecyclemaybeachievedinthesamechamber,
1. 52 0
2. 16 0.2
if it is capable of cooling to the lower defined temperature.
3. 4 1.0
Alternatively, the thermal cycle can be achieved by transfer
between the high-temperature chamber and a room-
6. Interferences
temperature environment or cold chamber, depending on the
6.1 Temperature—Because resistance of metallic conduc-
prescribed low temperature of the thermal cycle.
tors is a function of temperature, provision of a standard length
7.4 Power—A 50/60 Hz ac constant current supply is
of conductor wire has been provided to permit correction for
required,capableofcontinuouslymaintainingthespecifiedtest
room temperature changes for potential drop measurements.
current within 61 %. For safety reasons, the maximum output
However, degraded electrical connections among the test
potential at open circuit shall be 12 V and the supply output
samples can be a source of abnormal heat during the measure-
must be isolated from the 120/240 volt alternating current
ments (when current is flowing), causing temperature varia-
(VAC) primary circuit.
tions from point-to-point on the test assembly. If individual
7.5 Test Board—A mounting board or frame shall be pro-
connections are noted to be heating abnormally when potential
vided for the test samples such that the board or frame be inert
drop measurements are being made (as determined by rela-
with regard to humidity and dimensionally stable with regard
tively high potential drop), it is desirable to minimize tempera-
to the thermal cycle of 75°C temperature change. To the extent
ture nonuniformity by using temporary thermal isolation bar-
possible, the thermal expansion coefficient shall match that of
riers.
the material being tested. (Example: frame shall be aluminum
6.2 Current—Current variation during the measurement
if aluminum wire or cable is a major part of the connection
leads to erratic results. Calibration of the required constant
system being tested.) The board or frame shall provide for
current source shall be maintained.
mechanical mounting of the test samples such that individual
6.3 Instruments—Instrument stability shall be maintained
samples are independent of adjacent samples in regards to
by means of frequent calibration checks. Stability of reference
effects of mounting or the process of obtaining electrical
voltage drop across a standard resistor should be maintained to
measurements. As required by dimensions of the thermal or
within the instrument ratings by checks both before and after
humidity chambers used, the test sample population may be
each group of measurements.
divided among several test boards.
6.4 Magnetic Fields—Voltage signals resulting from stray
7.6 Temperature Measurement—Ambient and chamber
magnetic fields intersecting the voltage probe leads or power
temperature shall be measured by such apparatus as can detect
supply leads need to be assessed prior to beginning each series
0.5°C temperature change within the desired range. A cali-
of measurements. Generally, this can be done by moving the
brated glass thermometer is acceptable for this purpose.
leads and observing the resultant voltage changes. Alterna-
7.7 Current Measurement—An a-c ammeter capable of
tively, a source of stray magnetic field such as an energized
resolution of 0.5 % of the applied measurement current is
autotransformer can be moved adjacent to the measurement
required.
circuit for detection of voltage changes. If voltage
...
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