Cable Insulation Test Using Megger

Use megger on high resistance measurements only such as insulation measurements or to check two separate conductors on a cable.

Cable insulation test using megger.

A megger is an ohmmeter that measures resistance in the megohm scale. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. For cables above 300 volt to 600 volt use 1000 volt megger. For cables above and less than 1200 volt use 2500 volt megger.

The test measures the insu lation resistance between the phases and or between phase and ground. The insulation resistance test a k a the megger test is as relevant as ever and in many applications is preferred to other insulation test methods. De energize and discharge the circuit completely before connecting a megger. A megger sends voltage through a cable and measures any current leakage in megohms 1 000 ohms.

The cable s overall insulation system and will reveal localised problems such as poor joints and terminations. To test a cable with a megger you connect one probe to the outside of the cable and with the power turned off you touch the probe to the conducting wire at the point of connection. Applied potential shall be 500 volts dc for 300 volt rated cable and 1000 volts dc. Insulation resistance testing is a non destructive test procedure.

The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. For good insulation the resistance usually reads in the megohm range. Perform insulation resistance test on each conductor with respect to ground and adjacent conductors.

For cables 300 volt use 500 vdc megger. Cable testing and diagnostics provides information about the cable s global condition e g. The megger insulation tester is essentially a high range resistance meter ohmmeter with a built in direct current generator. Routine megger tests of aged electrical cable is a prudent way to ensure your circuits are safe from arc faults that can cause circuits to be blown and safe.

Testing electrical cable with a megohmmeter helps identify damage in the cable insulation. It will also reveal localised weak spots in the insulation. Never touch the test leads while the handle is being cranked. Insulation resistance testing purpose.

The megger insulation tester is essentially a high range resistance meter. The first dc portable insulation tester was developed in 1889 by our founders sydney evershed and ernest vignoles and by 1903 was being sold as a megger insulation tester. Cable testing and diagnostics.