Insulation Resistance Test Procedure

The test measures the insu lation resistance between the phases and or between phase and ground.

Insulation resistance test procedure.

The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c. Read the value of the resistance at the end of the minute test and note it in your table. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.

Hands down without a doubt one of the most universally searched topics on ec m s website from a historical perspective is insulation resistance testing as a result some of our most popular evergreen articles like understanding insulation resistance testing continue to top the charts when it comes to most popular content. The insulation resistance test is the second test required by the electrical safety testing standards. Using insulation testing with an instrument such as the fluke 1555 10 kv insulation tester combined with fluke connect technology such leaks can be detected as insulation resistance slowly tapers over time a sign of normal and expected deterioration. The measured resistance indicates the condition of the insulation between two conductive parts.

Since 80 of electrical maintenance and testing. Developed early in the 20th century the insulation resistance ir test is the oldest and most widely used test for assessing the quality of insulation. Insulation resistance testing purpose. 230v to measure insulation resistance in ohm s.

If you are testing insulation resistance to ground place the positive probe on the ground wire or the grounded metal junction box and the negative probe on the conductor or terminal. 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. Check full load amps flas with the appropriate meter when the motor is turned on or with a full preference. When performing insulation resistance testing you must maintain consistency.

For low voltage installations i e. With a little record keeping and common sense however you can get a good picture of the insulation condition from values that are only relative. Energize the megger for 1 minute. Check the motor frame earth from phase to phase u to e v to e w to e.

Because electrical insulation will exhibit dynamic behavior during the course of your test. Insulation resistance decreases in temperature or moisture. Good insulation shows this charge effect over a time period much longer than the time required to charge the capacitance of the insulation. Performing time resistance tests on large switchgear transformers bushings motors and cables especially at higher voltages require high insulation resistance ranges and clean consistent test voltages.

Insulation resistance testing is a non destructive test procedure. In other cases tests will detect a more serious issue in the moment when current. Set the voltage level of the insulation resistance tester to 500v.