For good insulation the resistance usually reads in the megohm range.
Cable insulation tester.
The megger insulation tester is essentially a high range resistance meter.
With advanced performance the insulation tester line is designed to be safe simple to use and gimmick free.
Whether the dielectric is good or bad to evaluate a number of test results on the same piece of equipment you have to conduct the test the same way and under the relatively same environmental parameters each and every time.
A cable insulation resistance test is a test that is performed by applying 500 v or more between the conductor and ground and measuring the resulting leakage current.
The insulation condition from values that are only relative.
Cable faults cost money and create disruption so there is an enormous demand for cable test techniques to ensure cables and joints are in good condition and to allow cable faults to be located rapidly.
An insulation resistance tester is a test instrument that measures current that leaks through the insulation into ground.
The first dc portable insulation tester was developed in 1889 by our founders sydney evershed and ernest vignoles and by 1903 was being sold as a megger insulation tester.
We look for corrosion on the copper cracks in the insulation moisture on the cables and many other indicators of damage to the cables.
Whether you work on motors generators cables or switch gear the fluke digital insulation resistance testers provide noise free reliable results.