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  • If you are referring to a megohm meter, it is a test of the insulation properties of such things as electric wiring, motor windings and high power antenna mounts.

    We use a "megger" or "meg out" electrical wiring and equipment to see if it is shorted to ground in any way.

    The megger uses much higher voltages to check resistance than a normal Volt-ohm meter.

    Ideally, you want infinity resistance but I've installed 460 volt motors with 750 meg ohms resistance to ground and had no problem.

  • On the whole megger testing is non destructive. What happens is a DC voltage is applied to the device or winding under test. It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it.

    On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing.

    Working voltages up to 240 volts should use the 300 range.

    Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range.

    As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.


As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.




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Q: What is a megger test?
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Related questions

What is the number of a megger test to shoot for?

A good number on a megger test should be around 2 megohms.

What is the importance of Megger test?

Megger tests are important because the test makes sure that your electrical insulation is safe and operating as intended. Megger tests are performed using a Meg-ohmmeter.

Can you megger or test an rcd?


What is the g in a megger test?

It is the terminal on the megger that the ground cable connect to when testing a device to ground.

How megger produce voltage?

The megger is used to find insulation resistance in any equipement. It will generate around 10kVA power to test.

What is the minimum resistance between phasea in megger test?


What type of voltage applied during megger test?


How much time duration is required while Meggar test is applied?

The time duration for a megger test is as long as it takes to turn the handle of the megger about five times. Voltage is generated on the first turn and if there is an insulation breakdown on the device being tested it will show instantaneously. If the megger is an electronic megger hold the generate button down for about three seconds.

What happens if a megger test fails?

If a megger test fails you have a short between the two wires or the wire to ground that you are testing. This short circuit has to be repaired before the equipment is placed back into service.

How do you test motor for burn?

To test a motor, use a megger (megohm meter) to test the insulation of the internal motor windings. Select a voltage to apply to the motor using an output from the megger that is higher that the operating voltage that the motor operates on.

What value of tester is to be used for measuring insulation resistance of three phase 600V cables?

The typical test equipment for this is a megger. The megger is connected to two conductors at a time to test the insulation between the two.

What is a Megger 1552 used for?

The Megger MFT 1552 is a combined electrical circuit tester which includes test features for Insulation testing, Earth loop impedance tests, RCD Testing and Continuity testing. It comes supplies with full Calibration Certificate.