A megger is also known simply as an insulation tester. It’s basically an ohmmeter, but it’s one that generates its own electricity under high DC voltages, such as 500 and 1,000 volts, and transmits it in small currents through the cable to be tested. The voltages are high, but the currents are small enough to be safe.
What does Meggered mean?
resistance of insulation
trademark an instrument that generates a high voltage in order to test the resistance of insulation, etc.
What are acceptable Megger test readings?
Anything reading between 2 megohms and 1000 megohms is usually considered a good reading, unless other problems have been noted. Anything less than 2 megohms indicates an insulation problem.
Can a Megger shock you?
Insulation testers are limited to no more than a few milli-Amps of test current. Remember, 5 milli-Amps will shock you, and 50 milli-Amps can kill you.
What is the difference between Hipot and Megger?
Both instruments apply a comparatively high voltage across insulation and draw leakage current through the insulation, commensurate with its insulating properties and condition. But, a megohmmeter gives the operator a measurement, while a high-pot takes action.
What is infinity on a Megger?
If your megohmmeter is reading “OL” (over load) or “I” (infinity), these are commonly used readings on megohmmeters when the measurement exceeds the maximum indicated value of the tester.
What is electrical Megger?
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.
Can a megger damage insulation?
Using a megger meter is not destructive. When insulation has been damaged, a megger tester is used in determining the cause by testing. The test is typically conducted at rates that are low as compared to the insulation. The insulation tests may range from as low as 40 V dc to 10 kV.
How do I use a Megger to test exposed conductors?
Locate the connection point of the wire or cable you want to test so you have access to the exposed conductors. Clamp the alligator clip on one of the megger probes to the wire or cable, touch the other probe to the exposed conductor and press the test button. The megger will generate a current between the probes,…
What is an electrical cable Megger used for?
The insulation of residential electrical cables deteriorates very slowly and will probably outlast the house. However, handy homeowners and appliance technicians may find a megger to be a useful tool for diagnosing faulty heat-generating elements, such as those in stoves and water heaters.
What happens if you short the probes on a Megger?
However, if you short the megger probes by touching them, you can still get a shock equivalent to the one you would get if you touched an electric fence. Like an ohmmeter, a megger has two probes – one of which usually has an alligator clip – and an analog or digital meter.
How do you read the resistance of a Megger?
The megger will generate a current between the probes, and the meter will record the resistance of the jacket to the flow of the current. Maintain contact for 30 to 60 seconds to get a reliable reading. Look for a resistance reading between 35 and 100 megohms.
