Cable Insulation Resistance Test Procedure

It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.

Cable insulation resistance test procedure.

Perform an insulation resistance test on each conductor with respect to ground and adjacent conductors. Test duration shall be one minute. Inspect exposed sections of cables and conductors for physical damage. 7 3 2 2 2 2009.

The test measures the insu lation resistance between the phases and or between phase and ground. This test is used to detect conductor insulation damage that may have been caused during installation. Locate the connection point of the wire or cable you want to test so you have access to the exposed conductors. An insulation resistance test is typically performed on de energized wire and cable immediately after installation and before termination to any equipment or accessories.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. 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. A cable insulation test is basically a continuity test so the power to the circuit must be off. What is insulation resistance testing.

Sample insulation resistance megohmeter test connections for cable and transformer using guard terminal. Perform insulation resistance test on each conductor with respect to ground and adjacent conductors. 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 is a non destructive test procedure.

The insulation resistance test is the second test required by the electrical safety testing standards. 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. Applied potential shall be 500 volts dc for 300 volt rated cable and 1000 volts dc for 600 volt rated cable. This is a simple nondestructive method of determining the condition of the cable insulation to check for contamination due to moisture dirt or carbonization.

Let s clarify our use of the term current. Test period must be for 1 minute using a voltage according to manufacturer s published data. Insulation resistance decreases in temperature or moisture. Replace or repair sections that exhibit damage.

Either turn off the breaker or if you re testing the wiring in a piece of equipment unplug it. When performing insulation tests on conductors and cable apply the following procedure. 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. General testing information for single conductor non shielded cable on a reel insulation resistance testing cannot be.