1.1 These specifications cover the equipment making up the temporary grounding system used on de-energized electric power lines, electric supply stations, and equipment.
1.2 It is common practice for the users of protective grounding equipment to prepare complete instructions and regulations to govern in detail the correct use and maintenance of such equipment.
1.3 The uses and maintenance of this equipment are beyond the scope of these specifications.
1.4 These specifications for a system of protective grounding utilizing copper cables are covered in four parts, as follows:
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Sections |
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Clamps for Temporary Protective Grounds |
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4 - 16 |
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Ferrules for Temporary Protective Grounds |
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17 - 30 |
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Cables for Temporary Protective Grounds |
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31 - 39 |
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Protective Grounds (Complete Assembly With Clamps, Ferrules, and Cable) |
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40 - 52 |
1.5 Each of the four parts is an entity of itself, but is listed as a part of the system for completeness and clarification.
1.6 Currents presented in Table 1 are based upon cable melting times, as determined from equations by I. M. Onderdonk and are to used in situations involving an asymmetry value less than 20 % (X/R ≤ 1.8). See Appendix X1.
Note 1: TPG testing is done on complete assemblies. Assembly ratings assume the grade of lowest graded component (see 43.1.6).
1.6.1 Currents presented in Table 2 are based upon the values from EPRI Project RP2446 Computer Program RTGC “A Desktop Computer Program for Calculating Rating of Temporary Grounding Cables” and are to be used in situations involving an asymmetry value greater than 20 % (X/R ≧ 1.8), see Appendix X2.
Note 1: The above current values are based on electromechanical test values.
Note 2: Assemblies that have been subjected to these shall not be re-used.
Note 3: For use with currents exceeding 20 % asymmetry factor.
Note 4: See X2.7.2 for additional information.
Note 5: Alternate testing circuits are available for laboratories that cannot achieve the above requirements. See Appendix X2 for details.
Note 1:
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