Electrical Insulation Resistance Test

The insulation resistance test is the second test required by the electrical safety testing standards.

Electrical insulation resistance test.

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 essentially a high range resistance meter ohmmeter with a built in direct current generator. Recommended test voltages for routine maintenance insulation resistance tests of equipment rated to 4 160v and above. When temperature increases insulation resistance decreases and vice versa.

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. The purpose of insulation is to prevent the flow of electric current between points of different potential in an electrical system. The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together. To prevent problems with your electrical equipment due to failure of insulation we recommend insulation tests be conducted regularly.

The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c. The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together. Failure of insulation is the most common cause of problems in electrical equipment. Insulation resistance testing or megger testing as it is more commonly known does what it says on the tin.

So to compare new readings with previous ones you ll have to correct your readings to some base temperature. For good insulation the resistance usually reads in the megohm range. 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. An infinite resistance would be the perfect result but no insulator is perfect so the higher the reading the better.

Insulation resistance is temperature sensitive. The measured resistance indicates the condition of the insulation between two conductive parts. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. The insulation resistance test is the second test required by the electrical safety testing standards.

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. A common rule of thumb is insulation resistance changes by a factor of two for each 10 degrc change. For low voltage installations i e. The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables.

230v to measure insulation resistance in ohm s. It tests the resistance of the insulation of all live parts in electrical circuits.