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Maurice Turgeon

United States

#45 Feb 22, 2010
I don't believe electrician training is the only place to obtain megger training, other sources have already been mentioned and this Forum IMO is also a good starting point.

True, 12V or 24V components would not survive a 1000V jolt and many cables won't survive more than twice their rating.

However cables in sensitive electronic equipment can be safely checked if disconnected from the sensitive components.

A megger, ohmeter, screwdriver etc. are just tools. We all learn from mentors, books and practice.

What I do notice is the enthusiasm in a lot of the posts by technicians writing in a foreign language, which I could not do, to try to expand their knowledge. Which I applaud.

San Salvador, El Salvador

#46 Apr 20, 2010
I have # 12 ,#10 & #8 THHN solid single conductor wire. How would I go about doing a megger Test on these wires,

What Reading should I be looking for. Bad & Good


#48 May 15, 2010
what is the lowest value of LV megger test for acceptance?


#49 Aug 16, 2010
well, connect the positive lead (usually color red) of the megger tester then the negative lead (usually color black) to the earth/ground,literally to the surface of the earth..

Tanzania, United Republic of

#50 Sep 19, 2010
I'ld like 2 know what megger tester is & wht are it's funxns

Dammam, Saudi Arabia

#51 Jan 10, 2011
Can anybody here tell me how to test a XLPE/PVC,0.6/1kV cable for insulation which was in operation for more than 20Years. Also i want to know that if this cable is tested at 1000/500V Megger what could be the acceptable M ohms and if I want to make use of this for 380V ? I need your help. please help me.
helal basho

Riyadh, Saudi Arabia

#52 Aug 25, 2011
Loganath wrote:
Post u r mail id, I'll send u a file, which will be useful to u in testing of cables<quoted text>
my e-mail is :[email protected]
thank you very much for youe assistance.
helal basho

Riyadh, Saudi Arabia

#53 Aug 25, 2011
my e-mail is : [email protected]
thank you very much for your aasitance


#54 Sep 29, 2011
Any one know list standard cable insulation? Help me
Muhasan Indonesia

Jakarta, Indonesia

#55 Jan 26, 2012
Megger like what is good quality and simple use of his


#56 Feb 8, 2012
please some body help me ,i want to know that 300sqmm voltage rating600/1000 v cable,i insulation testing at 500vmegger what could be the acceptable ohms and what is the lowers mohms/gohms/tohms.please solve my problum........thank you very much

Birmingham, AL

#57 Feb 8, 2012
Zahid, what you ask can only be addressed in generalities. If you megger 30 meters of cable (conductor-to-conductor)and get a reading of only 90 meg ohm that cable may be useable if it's not being used on a GFCI protected circuit and the enviromental conditions will not get worse. Such as; the moisture or temperature will not increase.

Also, if the cable is on a floor when tested it should be measured again after it's installed. And tested again as a preventative maintenance function every year after that. Record the values and test conditions and compare then with previous measurements.

Obviously, readings of old cable will never be better than readings of the same type of new cable. So, if you want to see if your cable has deteriorated you should compare the readings of your cable with radings of the same cable under the same enviromental conditions and lenght.

I personally would not use cable reading less than 50 meg ohm per 30 meters. It's reasonable to assume that that cable would only measure 25 meg ohms if it was 60 meters long etc.
Don Ray Tex

Hutto, TX

#59 Feb 5, 2013
If you want to "add to" then share your knowlege or if you feel the topic too complex refer them to a site where they can learn rather than referring to someone who is attempting to learn something as an "idiot".
Leo Pold

Central District, Hong Kong

#60 Mar 8, 2013
Can anyone help me what to use in meggering the 24VDC instrumentations? Is the insulation tester 250VDC, 500Mohms acceptable?
Maurice Turgeon

Birmingham, AL

#61 Mar 9, 2013
Leo, the general rule of thumb, is to megger at twice the voltage rating of the cable for one minute. Other than automotive wire, 300V is the minimum in the US.

Anything over 99 M ohm is very good and may be as good as the meter can read.

On single conductor cable I've heard of folks dropping a spool of wire in a tub of ordinary water, keeping the ends dry, and connecting the megger leads to one end of the wire, the other to the metal tub.

Since a megger uses very high voltages, one would have to be very careful to not get shocked!

The best method I know to determine good readings from bad readings is to compare each to new, good wire. Record your findings for future reference.

Pasadena, CA

#62 Jan 29, 2016
Why should we do megger testing
Why should we need it ?

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