ASTM B812-96(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: B812 − 96 (Reapproved 2013)
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 B812; 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.
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 1.3.4 This test method does not evaluate degradation which
may occur in residential applications due to exposure of the
1.1 This test method covers all residential pressure connec-
electrical connection system to additional environmental con-
tionsystems.Detailedexamplesofapplicationtospecifictypes
stituents such as (but not limited to) the following examples:
of connection systems, set-screw neutral bus connectors and
1.3.4.1 Household chemicals (liquid or gaseous) such as
twist-on wire-splicing connectors, are provided in Appendix
ammonia, bleach, or other cleaning agents.
X1 and Appendix X2.
1.3.4.2 Chemicals as may occur due to normal hobby or
1.2 The purpose of this test method is to evaluate the
professionalactivitiessuchasphotography,painting,sculpture,
performance of residential electrical pressure connection sys-
or similar activities.
tems under conditions of cyclic temperature change (within
1.3.4.3 Environments encountered during construction or
rating) and high humidity.
remodeling such as direct exposure to rain, uncured wet
1.3 The limitations of the test method are as follows:
concrete, welding or soldering fluxes and other agents.
1.3.1 This test method shall not be considered to confirm a
1.3.5 This test method is limited to evaluation of pressure
specific lifetime in application environments.
connection systems.
1.3.2 The applicability of this test method is limited to
1.4 This standard does not purport to address all of the
pressure connection systems rated at or below 600Vd-c or a-c
safety concerns, if any, associated with its use. It is the
RMS.
responsibility of the user of this standard to become familiar
1.3.3 This test method is limited to temperature and water
with all hazards including those identified in the appropriate
vapor exposure in addition to electrical current as required to
Material Safety Data Sheet (MSDS) for this product/material
measure connection resistance.
as provided by the manufacturer, to establish appropriate
safety and health practices, and determine the applicability of
regulatory limitations prior to use.
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
1.5 This standard should be used to measure and describe
B02.11 on Electrical Contact Test Methods.
the properties of materials, products, or assemblies in response
Current edition approved Aug. 1, 2013. Published August 2013. Originally
to electrical current flow under controlled laboratory condi-
approved in 1990. Last previous edition approved in 2008 as B812 – 96 (2008).
DOI: 10.1520/B0812-96R13. tions and should not be used to describe or appraise the fire
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B812 − 96 (2013)
hazard or fire risk of materials, products, or assemblies under 3.5 reference connection system, n—the reference connec-
actual installation conditions or under actual fire conditions. tion system is the same connection system as that which is
However, results of this test may be used as elements of a fire under evaluation, but which is exposed only to a dry environ-
risk assessment which takes into account all of the factors ment at normal room temperature.
which are pertinent to an assessment of the fire hazard of a
4. Summary of Test Method
particular end use.
4.1 The environmental exposure of the connections tested
2. Referenced Documents
consists of weekly sequences consisting of five thermal cycles
of 75°C temperature change (taking a maximum of8hto
2.1 ASTM Standards:
accomplish), followed by exposure for the balance of the week
B542 Terminology Relating to Electrical Contacts and Their
to conditions at or near 100 % relative humidity at room
Use
temperature. The text exposure cycle is repeated for a mini-
2.2 Underwriter Laboratory Standards:
mum of four one-week cycles. Reference connections are kept
UL486B Standard for Wire Connectors For Use With Alu-
3 in a dry environment at room temperature for the same
minum Conductors, ANSI/UL 486B
duration. Potential drop measurements, at rated current, are
UL486C Standard for Splicing Wire Connectors
made prior to each weekly environmental exposure cycle, and
2.3 NEC Document:
a final set of measurements is taken at the end of the test.
ANSI/NFPA 70 National Electric Code
5. Significance and Use
3. Terminology
5.1 The principal underlying the test is the sensitivity of the
3.1 residential applications, n—residential applications are
electricalcontactinterfacetotemperatureandhumiditycycling
those involving a structure or vehicle used entirely for perma-
that electrical pressure connection systems experience as a
nent or temporary human habitation. Included are homes
result of usage and installation environment. The temperature
(single or multiple-unit houses and mobile or modular
cyclingmaycausemicromotionatthematingelectricalcontact
structures), motels, hotels, dormitories, hospitals, rest homes,
surfaces which can expose fresh metal to the local ambient
and recreational vehicles. Excluded are railroad cars, boats,
atmosphere. The humidity exposure is known to facilitate
airplanes, nonresidential, commercial (office buildings, stores)
corrosion on freshly exposed metal surfaces. Thus, for those
and industrial applications (factories, warehouses).
connection systems that do not maintain stable metal-to-metal
3.2 pressure connection system, n—an electrical connection
contact surfaces under the condition of thermal cycling and
intended to carry current between components or conductors in
humidity exposure, repeated sequences of these exposures lead
contact under mechanical pressure.
to degradation of the contacting surface indicated by potential
3.2.1 Discussion—The mechanical pressure may be applied
drop increase.
by clamping, tightening of threaded components, spring force,
5.2 The test is of short duration relative to the expected life
crimping, swaging, or other means. For the purpose of the test
of connections in residential usage. Stability of connection
procedure, the connection system consists of all components
resistance implies resistance to deterioration due to environ-
normally present in the application, including both current-
mental conditions encountered in residential service. Increas-
carrying and other metallic components, and non-metallic
ing connection resistance as a result of the test exposure
components (insulators, insulation, protective boots or sleeve,
indicates deterioration of electrical contact interfaces. Assur-
etc.). Also see definition of “Connection, Pressure
anceoflongtermreliabilityandsafetyofconnectiontypesthat
(Solderless),” in Article 100 of reference noted in Section 2.3
deteriorate requires further evaluation for specific specified
(NEC).
environments and applications.
3.3 aluminum, n—as the term “aluminum,” the material of
5.3 Use—It is recommended that this test method be used in
which conductors (wire, cable, busbars, etc.), connection
one of two ways. First, it may be used to evaluate and report
components,andtestboardcomponentsmaybemade,includes
the performance of a particular connection system. For such
aluminum metal and its alloys.
use, it is appropriate to report the results in a summary (or
3.4 reference conductor, n—a continuous length of the same
tabular) format such as shown in Section 17, together with the
conductor material (wire, cable, busbar, etc.) incorporated in
statement “The results shown in the summary (or table) were
the connection system being tested by being mounted on the
obtained for (insert description of connection) when tested in
same test board assembly and connected in the same series
accordance with Test Method B812. Second, it may be used as
circuit.
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.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Specificationofconnectionsystemsinaccordancewiththisuse
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
of the standard test method would be of the form: “The
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
maximum potential drop increase for any connection, when
Available from Underwriters Laboratories (UL), 333 Pfingsten Rd.,
tested in accordance with Test Method B812 for a period of
Northbrook, IL 60062-2096, http://www.ul.com.
weeks, shall be mV relative to the reference connections.”
Available from National Fire Protection Association (NFPA), 1 Batterymarch
Park, Quincy, MA 02169-7471, http://www.nfpa.org. Connection systems that are most resistant to thermal-cycle/
B812 − 96 (2013)
humidity deterioration, within the limitations of determination such that no contamination of test samples or deionized water
bythistestmethod,shownoincreaseinpotentialdrop,relative occurs. The vessel is to be operated in a normal laboratory
to the reference connections, when tested for indefinite time. environment which has continuous temperature control during
Connections that are less resistant to thermal-cycle/humidity the period of the test.
conditions applied by this test will demonstrate progressive
NOTE 1—This apparatus is intended to expose samples to relative
increases in potential drop with increasing time on test. Thus,
humidity at or near 100 %.
the following examples of specifications are in the order of
7.3 Temperature Chamber—The temperature chamber shall
most stringent (No. 1) to least stringent (No. 3).
be capable of control at the defined upper temperature of the
Duration, weeks Maximum Potential Drop Increase, mV
thermal cycle such that chamber temperature stability,
1. 52 0
uniformity, and control accuracy shall be within 62°C. The
2. 16 0.2
3. 4 1.0
lower temperature of the cycle may be achieved in the same
chamber, if it is capable of cooling to the lower defined
6. Interferences
temperature. Alternatively, the thermal cycle can be achieved
6.1 Temperature—Because resistance of metallic conduc-
by transfer between the high-temperature chamber and a
tors is a function of temperature, provision of a standard length
room-temperature environment or cold chamber, depending on
of conductor wire has been provided to permit correction for
the prescribed low temperature of the thermal cycle.
room temperature changes for potential drop measurements.
7.4 Power—A 50⁄60 Hz ac constant current supply is
However, degraded electrical connections among the test
required,capableofcontinuouslymaintainingthespecifiedtest
samples can be a source of abnormal heat during the measure-
current within 61 %. For safety reasons, the maximum output
ments (when current is flowing), causing temperature varia-
potential at open circuit shall be 12 V and the supply output
tions from point-to-point on the test assembly. If individual
must be isolated from the 120/240 volt alternating current
connections are noted to be heating abnormally when potential
(VAC) primary circuit.
drop measurements are being made (as determined by rela-
tively high potential drop), it is desirable to minimize tempera- 7.5 Test Board—A mounting board or frame shall be pro-
vided for the test samples such that the board or frame be inert
ture nonuniformity by using temporary thermal isolation bar-
riers. with regard to humidity and dimensionally stable with regard
to the thermal cycle of 75°C temperature change. To the extent
6.2 Current—Current variation during the measurement
possible, the thermal expansion coefficient shall match that of
leads to erratic results. Calibration of the required constant
the material being tested. (Example: frame shall be aluminum
current source shall be maintained.
if aluminum wire or cable is a major part of the connection
6.3 Instruments—Instrument stability shall be maintained
system being tested.) The board or frame shall provide for
by means of frequent calibration checks. Stability of reference
mechanical mounting of the test samples such that individual
voltage drop across a standard resistor should be maintained to
samples are independent of adjacent samples in regards to
within the instrument ratings by checks both before and after
effects of mounting or the process of obtaining electrical
each group of measurements.
measurements. As required by dimensions of the thermal or
humidity chambers used, the test sample population may be
6.4 Magnetic Fields—Voltage signals resulting from stray
divided among several test boards.
magnetic fields intersecting the voltage probe leads or power
supply leads need to be assessed prior to beginning each series
7.6 Temperature Measurement—Ambientandchambertem-
of measurements. Generally, this can be done by moving the
perature shall be measured by such apparatus as can detect
leads and observing the resultant voltage changes.
0.5°C temperature change within the desired range. A cali-
Alternatively, a source of stray magnetic field such as an
brat
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