ASTM G165-99(2017)
(Practice)Standard Practice for Determining Rail-to-Earth Resistance
Standard Practice for Determining Rail-to-Earth Resistance
SIGNIFICANCE AND USE
4.1 Low resistance between the rails and earth could result in large magnitudes of stray earth currents with the attendant corrosion damage to underground metallic structures.
4.2 These measurements are of a low voltage type and are not designed to evaluate the high voltage dielectric characteristics of the rail insulating elements.
4.3 Sections of track with rail-to-earth resistances less than acceptable minimums must be tested in greater detail to determine the reason(s) for this condition. Determination of the reason(s) for any low rail-to-earth resistance may require the use of special testing techniques or special instruments, or both, beyond the scope of this practice.
4.4 The electrical tests call for the use of electric meters that have varying characteristics depending on cost, manufacture, and generic type. It is assumed that any person employing the test procedures contained herein will know how to determine and apply proper correction factors and that they will have sufficient knowledge to ensure reasonable accuracy in the data obtained.
4.5 This practice does not encompass all possible field conditions to obtain rail-to-earth resistance characteristics. No general set of test procedures will be applicable to all situations.
SCOPE
1.1 This practice covers the procedures necessary to follow for measuring resistance-to-earth of the running rails which are used as the conductors for returning the train operating current to the substation in electric mass transit systems.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G165 − 99 (Reapproved 2017)
Standard Practice for
Determining Rail-to-Earth Resistance
This standard is issued under the fixed designation G165; 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.
1. Scope 3.1.3 impedance bond—a device connected to running rails
for automatic train operations.
1.1 This practice covers the procedures necessary to follow
for measuring resistance-to-earth of the running rails which are 3.1.4 The terminology used herein, if not specifically de-
used as the conductors for returning the train operating current fined otherwise, shall be in accordance with Terminology G15.
to the substation in electric mass transit systems. Definitions provided herein, and not given in Terminology
G15, are limited to this practice.
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
4. Significance and Use
only.
4.1 Low resistance between the rails and earth could result
1.3 This standard does not purport to address all of the
in large magnitudes of stray earth currents with the attendant
safety concerns, if any, associated with its use. It is the
corrosion damage to underground metallic structures.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.2 These measurements are of a low voltage type and are
bility of regulatory limitations prior to use. not designed to evaluate the high voltage dielectric character-
1.4 This international standard was developed in accor- istics of the rail insulating elements.
dance with internationally recognized principles on standard-
4.3 Sections of track with rail-to-earth resistances less than
ization established in the Decision on Principles for the
acceptable minimums must be tested in greater detail to
Development of International Standards, Guides and Recom-
determinethereason(s)forthiscondition.Determinationofthe
mendations issued by the World Trade Organization Technical
reason(s) for any low rail-to-earth resistance may require the
Barriers to Trade (TBT) Committee.
use of special testing techniques or special instruments, or
both, beyond the scope of this practice.
2. Referenced Documents
4.4 The electrical tests call for the use of electric meters that
2.1 ASTM Standards:
have varying characteristics depending on cost, manufacture,
G15 Terminology Relating to Corrosion and Corrosion Test-
and generic type. It is assumed that any person employing the
ing (Withdrawn 2010)
test procedures contained herein will know how to determine
3. Terminology and apply proper correction factors and that they will have
sufficient knowledge to ensure reasonable accuracy in the data
3.1 Definitions of Terms Specific to This Standard:
obtained.
3.1.1 cross bond—insulated copper cables that connected
4.5 This practice does not encompass all possible field
between adjacent sections of track to ensure electrical conti-
nuity between them. conditions to obtain rail-to-earth resistance characteristics. No
general set of test procedures will be applicable to all situa-
3.1.2 direct fixation fastener—adeviceforfasteningrunning
tions.
rails to their support structures.
5. Equipment
This practice is under the jurisdiction of ASTM Committee G01 on Corrosion
5.1 Indicating dc; high impedance (minimum ten megohm)
of Metals and is the direct responsibility of Subcommittee G01.10 on Corrosion in
Soils.
voltmeter (two required); multi-scale, capable of reading posi-
Current edition approved May 1, 2017. Published May 2017. Originally
tive and negative values without removing test leads; and
approved in 1999. Last previous edition approved in 2012 as G165 – 99 (2012).
covering at least the following full scale ranges:
DOI: 10.1520/G0165-99R17.
5.1.1 0 to 10 mV,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1.2 0 to 100 mV,
Standards volume information, refer to the standard’s Document Summary page on
5.1.3 0 to 1 V,
the ASTM website.
5.1.4 0 to 10 V, and
The last approved version of this historical standard is referenced on
www.astm.org. 5.1.5 0 to 100 V.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G165 − 99 (2017)
5.1.6 Meters shall be accurate within 1 % of full scale. 7. Electrical Tests
7.1 Electricallyisolatesectionsoftrack(seetypicalarrange-
5.2 Direct current ammeter, multi-scale, covering the fol-
ments in Figs. 1 and 2). Length of track section to be tested is
lowing full scale ranges:
dependent upon the locations of rail insulators. Rail insulators
5.2.1 0 to 1 A,
are found at the ends of turnouts and single and double
5.2.2 0 to 10 A, and
crossovers. The lengths of the track sections will vary within
5.2.3 0 to 100 A.
the general range of 60 to 2750 m (200 to 9000 ft).
5.3 Direct current milliammeter, multi-scale, covering the
7.1.1 Remove cable connections from across rail insulators.
following full scale ranges:
7.1.2 Disconnect cross bonds within section of track being
5.3.1 0 to 15 mA,
tested and other track.
5.3.2 0 to 150 mA, and
7.1.3 Disconnect power traction substation negative feeder
5.3.3 0 to 1500 mA,
cables from track section being tested.
5.4 An alternative to the ammeter and milliammeter is a
NOTE 1—Switches within substation can be opened.
millivolt meter and external shunts covering the listed current
7.2 Ensure electrical continuity between the rails within the
ranges. Meters (and shunt combinations if used) shall be
insulated track section being tested by the use of the existing
accurate to within 1 % of full scale.
cables at impedance bonds or by installing temporary wire
5.5 Direct current power source with control circuits.
connections between the rails.
Generally, 6 or 12 V automotive type wet cell batteries will
7.3 Track-to-earthresistancemeasurementswillbeobtained
suffice.
as shown on Fig. 3 for main track sections and as shown on
5.6 Test wires, assorted lengths and sizes, to suit field Fig. 4 for main track sections containing double crossovers.
conditions. Wires should have minimum 600 V insulation in Measurements on track sections containing turnouts and single
perfect condition (no visible cuts or abrasions) and be multi- crossovers will be similar to that shown on Fig. 4 with the
strand copper conductors for flexibility. number of test points being determined by the electrical
configuration of insulating joints and bonding cables.
5.7 Miscellaneous tools as required for making wire
7.4 The track-to-earth resistance measurements for the track
connections, splicing, and so forth.
in the train storage yards will require special consideration for
5.8 Vehicle to transport equipment and personnel along
each section to be tested because of the number and location of
track to facilitate testing.
insulating joints resulting from the type of signal system being
used within the yard area and because of the number of cross
6. Visual Inspection
bonds and other bonding cables used within the yard.
6.1 The track section to be tested should be visually
7.5 All data shall be recorded.
examined to ensure the insulating components have been
7.6 A sketch showing location of the test and the electrical
installed and there is no debris, water, or other conductive
test set-up used shall be included.
material in electrical contact with the metallic track compo-
nents that could result in the lowering of the effective track- 7.7 The number of readings taken to determine an electrical
to-earth resistance thus producing incorrect data. constant or property must be sufficient to ensure that random
FIG. 1 Schematic Diagram — Typical Mainline Track Section
G165 − 99 (2017)
FIG. 2 Schematic Diagram — Typical Double Crossover Track Section
NOTE 1—All cable connections removed for measurements as shown on Fig. 1.
NOTE 2—Ground resistance to be on the order of 1/100 (or less) of the track-to-earth resistance for the section being tested.
FIG. 3 Schematic Diagram — Mainline Test Arrangement
NOTE 1—All cable connections removed for measurements as shown on Fig. 2.
NOTE 2—Ground resistance to be on the order of 1/100 (or less) of the track-to-earth resistance for the section being tested.
FIG. 4 Schematic Diagram — Double Crossover Test Arrangement
G165 − 99 (2017)
NOT
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