From Omni Controls, Inc.
When voltage is impressed across any insulation system, some current leaks into, through, and around the insulation. When testing with dc highvoltage, capacitive charging current, insulation absorption current, insulation leakage current, and by-pass current are all present to some degree. For the purposes of this document on cable fault locating, only leakage current through the insulation will be considered.
For shielded cable, insulation is used to limit current leakage between the phase conductor and ground or between two conductors of differing potential. As long as the leakage current does not exceed a specific design limit, the cable is judged good and is able to deliver electrical energy to a load efficiently.
Cable insulation may be considered good when leakage current is negligible but since there is no perfect insulator even good insulation allows some small amount of leakage current measured in microamperes.
Product Announcements
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The HP91 performs high voltage insulation tests including AC Hipot, DC Hipot and the insulation resistance (IR) test. It is intended for production, repair or compliance testing of motors,...
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Megger introduces the new family of 5 and 10 kV insulation testers comprised of three analog/digital models.
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Locates current in hidden wires and cables...
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Topics of Interest
4.4 INSULATING MATERIALS
General Properties
Original material by T.W.DAKIN (deceased)
Electrical Insulation and Dielectric Defined. Electrical insulation is a medium or a material...
Ground-fault circuit interrupters (GFCIs), also called earth leakage or residual-current circuit breakers, can sense leakage current to earth ground from live parts and interrupt the circuit...
Overview
When the current flow path is directed correctly, the pressure of the source voltage forces normal current magnitudes to flow through the load impedances. During this time, the insulation...
In an industry comprised of workers with varying electronics knowledge, a Hipot test can seem a daunting task for some. Indeed, many test operators and quality assurance supervisors, having never been...
Every electric wire in your plant - whether it's in a motor, generator, cable, switch, transformer, etc. - is carefully covered with some form of electrical insulation. The wire itself is usually...
