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Standards for Insulating links
ANSI/CPLSO-14
ANSI/UL2737 (Withdrawn)
ASTM F2973
MIL-L-24410 (Withdrawn)
Tests by Independent Organizations
Load Insulator
Miller & Hirtzer
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PAGE 2 The Standard The ASTM standard F2973‐16 in its scope indicates that it applies to links whose primary application is related to power line electrical safety. It includes specification of design, material and testing requirements for the manufacture and in‐service inspection testing and care requirements for the user or the agent of the user. Evaluation I do not intend in this evaluation to touch on the materials or manufacture of the insulating link devices. My evaluation with focus for the most part on the electrical testing methods and some on the mechanical testing of the devices. GENERAL TESTING COMMENTS The first failing of the standard is the allowance of a test of one device. A proper approach would require a random selection from manufacturing of at least 3 devices. This requirement was pointed out by negative votes during the creation of the standard. It would seem to this writer that since this is a life safety device that the members of the committee creating the standard would require more than one device for testing to assure that the manufacturing methods consistently produce uniform products. The second concern is that some of the general test requirements are not associated with the quality of or methods of testing. Nothing is said about proper instrumentation and shielding that might affect the measurement of the leakage current. It is strange that the test location shall not be below 15.5 degrees considering that the link will be used in the field in temperatures from below freezing to extreme heat. The third concern is the allowance of dc testing. This error was pointed out by negative votes during the creation of the standard and is discussed in detail below. The fourth concern is the lack of mechanical testing as a part of the standard except for an in‐service test. This device must meet or exceed all the mechanical specifications for hooks and hardware for a lift device based on its capabilities for lifting plus margins of safety and is discussed below.
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