Megger Test Results

[cvirgil]

I'm reviewing results from a megger test on 600V condcutors from Phase to ground and Phase to Phase.

A-G = 700Megohm
B-G = 1000Megohm
C-G = 800Megohm

A-B = 1600Megohm
B-C = 1580Megohm
A-C = 1400Megohm

Any idea as to why the values are different? All phase condcutors are the same length.

 

[rbulsara]

To me it looks good. Meggering is not an exact value test but a order of magnitude type of test for initial testing.

 

[waross]

I agree with rbulsara.
Your readings look very good.
yours

 

[Zogzog]

For IR testing it is not the values that are important (As long as everything is >100M), its the trend. Keep these results to compare the results next time you test these to predict expected life of your insulation.

Scott Peterson
Training Manager
Power Plus Engineering

http://www.epowerplus.com

 

[rbulsara]

To add to what zogzog indicated, make sure you record ambient conditions for all megger (insulation resistance) testing, such as temperature, humidity, weather, any relavant condition of the cables etc. These all have an effect on meggar reading and has to be evaulated by an experienced person.

 

[sparky321]

I agree totally with rbulsara, It is critical to record those parameters. If not you could see increases or decreases in your readings.
Jim Jimmmer Jim

 

[Zogzog]

Thanks guys I forgot to mention that. IR readings should be corrected to 20 degrees C. Humidity will affect the results but there is no method for humidty correction so your best bet is to try to test about the same time of the year where humidity levels are about the same as the last test.

Scott Peterson
Training Manager
Power Plus Engineering

http://www.epowerplus.com