Electrical Insulation Resistance Test

The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together.

Electrical insulation resistance test.

Failure of insulation is the most common cause of problems in electrical equipment. It tests the resistance of the insulation of all live parts in electrical circuits. Second the range of a megohmmeter is in megohms as its name implies instead of ohms as in a multimeter. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.

The measured value is then compared with minimum values stated in the standard in order to verify that there is not a breakdown of insulation caused by damage to cables and other component parts of a circuit. The insulation resistance test is the second test required by the electrical safety testing standards. Megger mit1020 10 kv insulation resistance testers are all designed specifically to assist the user with the testing and maintenance of high voltage equipment. A common rule of thumb is insulation resistance changes by a factor of two for each 10 degrc change.

The measured resistance indicates the condition of the insulation between two conductive parts. The purpose of insulation is to prevent the flow of electric current between points of different potential in an electrical system. For good insulation the resistance usually reads in the megohm range. The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together.

When temperature increases insulation resistance decreases and vice versa. 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 is temperature sensitive. As a production test this test is often used as a customer acceptance test with minimum insulation resistance per unit length often specified by the customer.

So to compare new readings with previous ones you ll have to correct your readings to some base temperature. For low voltage installations i e. The megger insulation tester is essentially a high range resistance meter ohmmeter with a built in direct current generator. Insulation resistance testing or megger testing as it is more commonly known does what it says on the tin.

Recommended test voltages for routine maintenance insulation resistance tests of equipment rated to 4 160v and above. The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. The insulation resistance test is the second test required by the electrical safety testing standards. An infinite resistance would be the perfect result but no insulator is perfect so the higher the reading the better.

This test is to measure the total resistance of a product s insulation by applying a voltage of 500 v 1000 v for low voltage systems. 230v to measure insulation resistance in ohm s.