Insulation Resistance Test Procedure

Insulation resistance testing is a non destructive test procedure.

Insulation resistance test procedure.

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 decreases in temperature or moisture. After the required connections are made you apply the test voltage for a period of one min. For low voltage installations i e.

The insulation resistance test is the second test required by the electrical safety testing standards. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c. 1 short time or spot reading test.

Let s clarify our use of the term current. 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. 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. The measured resistance indicates the condition of the insulation between two conductive parts.

What is insulation resistance testing. The test measures the insu lation resistance between the phases and or between phase and ground. The minimum test value of motor insulation resistance is 1 meg ohm 1 mh. 230v to measure insulation resistance in ohm s.

General testing information for single conductor non shielded cable on a reel insulation resistance testing cannot be. Check full load amps flas with the appropriate meter when the motor is turned on or with a full preference clamp meter unnamed napplet fla. Set the voltage level of the insulation resistance tester to 500v. Tests are typically conducted by applying a direct current dc voltage to the conductor under test and measuring the current that flows through insulation called the leakage current and into the non current carrying metal parts of equipment.

Basically there are three different tests that can be done using a megohmmeter. Check the motor frame earth from phase to phase u to e v to e w to e. In other cases tests will detect a more serious issue in the moment when current suddenly drops and returns. Basically you re applying a voltage specifically a highly regulated stabilized dc voltage across a dielectric measuring the amount of current flowing through that dielectric and then calculating using ohm s law a resistance measurement.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. 1 insulation resistance ir this is the simplest of the tests.