Cable Insulation Resistance Test Sheet

Additional equipment for testing major cables very low frequency vlf high voltage test set for xlpe cables.

Cable insulation resistance test sheet.

Insulation resistance testing is a non destructive test procedure. To measure insulation resistance from a conductor to the outside of the cable we need to connect the line lead of the megger to one of the conductors and connect the earth lead of the megger to a wire wrapped around the sheath of the cable. The method of measuring the insulation resistance is to test and assess the state of the isolation head and body how do you check for a broken wire. The test measures the insu lation resistance between the phases and or between phase and ground.

Let s clarify our use of the term current. Earth fault loop impedance efli 8 3 9. Check for a broken wire or bad plug connection in an extension cord by bending the cord along its length. Operation of rcd s test.

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. Maintenance insulation resistance testing can be performed on a regular basis and the collected data used to indicate if the conductor insulation is deteriorating over time. Insulation resistance testing purpose. Let s us check one situation where the insulation resistance is to be tested in a two wire cable.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. Correct circuit connections test. 8 3 7 this test completes the active neutral transposition test neutral not switched.

Performed as a step test cables discharged 4 times test duration after test ieee 400 2012 omnibus ieee guide for field testing and evaluation of the insulation of shielded power cable systems rated 5 kv and above. 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. 8 3 8 this test completes the neutral earth transposition test active and neutral belong to the same circuit. What is insulation resistance testing.

5kv insulation resistance tester 10 kv for 12 7 22 and 19 33 kv cables. The ohmmic value of the insulation resistance is expressed in megohms mω. If the insulation resistance falls below an accepted user dictated value or falling rapidly over time then cable. For good insulation the resistance usually reads in the megohm range.

It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. 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. This type of test is a form of preventative maintenance.