There are a variety of technologies and methods used to test the insulation of wire and cable, including high-potting, very low frequency (VLF), power factor, partial discharge, time-domain reflectometry (TDR), and “thumping.” Like a visit to the doctor’s office, each test examines the test item in a different way and looks for a different response [...]
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Tenants of the Time & Life Building in New York’s Rockefeller Center include Time Inc., publisher of more than 100 magazines. In an effort to “green” the building, shaft grounding rings have been installed to protect the bearings of HVAC fan motors. Proper tuning of a variable frequency drive’s output range and proper grounding of [...]
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“Where the cow won’t give milk anymore” is a standard lyric in old classic country songs; perhaps you’ve wondered why. Well, back in the early days many strange and downright bizarre occurrences happened on the farm, most of which were thought to be the product of superstition, bad living or old wives’ tales; but that [...]
(6 votes, average: 2.50 out of 5)
Medium voltage systems are defined by the IEEE as those operating at voltage levels greater than 1,000 volts and up to 72,000 volts. High voltage is defined by NEC 490.2 as any system operating at “more than 600 volts, nominal.” Field electrical inspectors may be asked to inspect medium voltage installations in the course of [...]
(2 votes, average: 3.50 out of 5)
Based on the response to recent seminars, the topic of medium voltage equipment and installations is one of high interest. This article will provide a brief history of the evolution, as seen by the author, of the industry and give a high-level overview of a few key areas from the product standpoint and terminology. Not [...]
(2 votes, average: 5.00 out of 5)
IAEI, as the keystone of the electrical industry, is a membership driven, non-profit association promoting electrical safety throughout the industry by providing premier education, certification of inspectors, advocacy, partnerships and expert leadership in Electrical Codes and Standards development.
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