Electrical Insulation Resistance Testing

For good insulation the resistance usually reads in the megohm range.

Electrical insulation resistance testing.

230v to measure insulation resistance in ohm s. The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c. Recommended test voltages for routine maintenance insulation resistance tests of equipment rated to 4 160v and above. Insulation resistance test between wiring conductors to ensure that the insulation of the cables or wires is not damaged and there is no leakage between them this test is performed.

What is insulation resistance testing. Let s clarify our use of the term current. 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. This type of initial test is usually referred to as a proof test.

It tests the resistance of the insulation of all live parts in electrical circuits. Main switch in off position. The insulation resistance test consists in measuring the insulation resistance of a device under test while phase and neutral are short circuited together. Insulation resistance testing or megger testing as it is more commonly known does what it says on the tin.

When installing new electrical machinery or equipment testing insulation resistance is important for two reasons. Should be as under. Second the range of a megohmmeter is in megohms as its name implies instead of ohms as in a multimeter. For low voltage installations i e.

The ohmmic value of the insulation resistance is expressed in megohms mω. The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. Before performing this test the position of the main switch fuses switches etc. The megger insulation tester is essentially a high range resistance meter ohmmeter with a built in direct current generator.

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 measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. First it ensures that the insulation is in adequate condition to begin operation. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.

The results obtained from ir test are not intended to be useful in finding localized defects in the insulation as in a true hipot test but rather give information on the quality of the bulk material used as the. 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. Its objective is to measure the ohmmic value of the insulation under a direct voltage of great stability generally 50 100 250 500 or 1000 vdc.