Electrical Cable Insulation Testing Procedure

The megger test is a method of testing making use of an insulation tester resistance meter that will help to verify the condition of electrical insulation.

Electrical cable insulation testing procedure. Measurement of dielectric strength and detection of short circuits. Nevertheless even today insulation is subject to many. The insulation test can perform. When your plant electrical system and equipment are new the electrical insulation should be in top notch shape.

To measure electrical leakage in wire we pass the current through devices then. The vlf test can be used in a. Because electrical insulation will exhibit dynamic behavior during the course of your test. As higher voltage vlf equipment is developed standards may be adapted to increase the voltage level for application.

What makes insulation go bad. The procedure for vlf testing is nearly identical to that of dc hi pot testing and is also conducted as a go no go test. From 20v to 2000v. Insulation resistance quality of an electrical system degrades with time environment condition i e.

Determining insulation resistances from fifty kilo ohm to two thousand mega ohm at high voltage i e. We verify the electrical insulation level in any device such as a motor cable and transformer. Furthermore manufacturers of wire cable motors and so on have continually improved their insulations for services in industry. The insulation test proceeds as follows.

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 test is basically a continuity test so the power to the circuit must be off. The insulation test combines several functions. The result of this can be measured in terms of mega ohm.

Deviations from the baseline information permit evaluation of the insulation. Locate the connection point of the wire or cable you want to test so you have access to the exposed conductors. Vlf testing of cables is supported in iec 60502 up to 35 kv and in ieee 400 2 up to 69 kv. Dc testing has also been shown to reduce the remaining life of cables with aged polymer insulation.

Temperature humidity moisture and dust particles. If the cable can withstand the applied voltage for the duration of the test it. Test results are dependent on the temperature of the insulating material and the humidity of the surrounding environment at the time of the test. Table 100 22 minimum radii for power cable.

Insulation resistance test data may be used to establish a trending pattern. Either turn off the breaker or if you re testing the wiring in a piece of equipment unplug it.