ASTM F855-2017 pdf free download

ASTM F855-2017 pdf free download.Standard Specifications for Temporary Protective Grounds to Be Used on De-energized Electric Power Lines and Equipment
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 continuous current rating—designated RMS current which can be carried continuously under specified conditions. 3.1.2 protective ground assembly—a temporary electrical connection between a source of potential energization and the earth, rated for the maximum anticipated fault current or continuous induced current, or both. 3.1.2.1 Discussion—Throughout this specification, kc mil = 1000 circular mils. 3.1.3 protective grounding equipment—devices installed temporarily on de-energized electric power circuits for the purposes ofpotential equalization and to conduct a short circuit current for a specified duration (time). 3.1.4 time to failure—failure time of the cable is the time between the initiation of current flow and the instant at which arcing begins. 3.1.5 ultimate capacity—this represents a current which it is calculated the component is capable of conducting for the specified time. It is expected that component damage may result. The component shall not be reused, except in test situations. 3.1.6 withstand rating—this represents a near symmetrical current which shall be conducted without any component being damaged sufficiently to prevent being operable and reusable. The protective ground shall be capable ofpassing a second test at this current after being cooled to ambient temperature.
5. Classification
5.1 Clamps are furnished in, but not limited to, three types according to their function and method of installation, as follows: 5.1.1 Type I—Clamps for installation on de-energized con- ductors equipped with eyes for installation with removable hot sticks. 5.1.2 Type II—Clamps for installation on de-energized con- ductors having permanently mounted hot sticks. 5.1.3 Type III—Clamps for installation on permanently grounded conductors or metal structures with tee handles, and eyes or square or hexagon head screw(s), or both. 5.1.4 Other types ofspecial clamps, such as those for cluster grounds or for underground equipment grounding, may be made, tested, and certified by the manufacturer as meeting the requirements of this specification. 5.1.5 Separable insulated connectors used in manufacturing underground equipment grounding assemblies shall meet the requirements of IEEE 386. 5.2 Clamps are furnished in grades according to mechanical strengths, short circuit capabilities, and duration of faults, as indicated in Table 1 or Table 2. For Table 1 grade designations, clamp ratings must include maximum use current and indica- tion whether testing was done at Ultimate or Withstand Ratings. The maximum use current listed shall not exceed the test current used in their electrical short circuit design tests (per 12.3.4). 5.3 Clamps are furnished in two classes according to the characteristics of the main contact jaws: 5.3.1 Class A—Clamp jaws with smooth contact surfaces. 5.3.2 Class B—Clamp jaws with serrations, or cross hatching, or other means intended to abrade or bite through corrosion products on the surfaces of the conductor being clamped.
9. Electrical and Mechanical Properties
9.1 Electrical and mechanical properties shall conform to the requirements prescribed in Table 1 or Table 2, as appropriate, and the following paragraphs. See Appendix X1 for a discussion and derivation of the current levels in Table 1. See Appendix X2 for a discussion of the effects of asymmetri- cal current and the derivation of the currents in Table 2. 9.1.1 Types I and II stick installed clamps shall be designed such that a failure does not increase the risk of injury to the user or have excess mechanical strength to prevent failure, defined as follows: 9.1.1.1 In the event the clamp is over-torqued during installation, normal fracture shall be such that the attached cable remains under control by being retained with the stick. 9.1.1.2 Clamps with an ultimate torque strength exceeding 45 N·m (400 lbf·in.) are exempt from the provisions of 9.1.1.1. 9.1.2 Resistance from the main contact to the attached cable contact shall be less than that for an equal length of maximum size cable(s) for which the clamp is rated. 9.1.3 Main contacts shall accept and clamp all conductors or structural members in accordance with the manufacturer’s rating. 9.1.4 Clamp shall accept hand assembly of all cables fitted with compatible ferrules as rated per Table 3. 9.1.5 Cable termination shall include a cable support or shall be made to accept a cable supporting ferrule. This support shall secure the entire cable over the jacket and is provided in addition to the electrical connection to the strand.