Megohmmeter

J. Schwiebert · Oct 25, 2015

I was helping my boy on installing a heat cable and it said to check the cable with a megohmmeter. Anybody have one or use one? We used a good Ohmmeter. Comments? Thanks. J.

Bill in IN · Oct 25, 2015

A "Megger" is simply an ohmmeter that use 500 volts DC instead of the usual 9 volts. It will find much lower level leakages in insulation. They sound like they are lawyering a little. Is the cable powered through a ground fault? If so I wouldn't worry with it.

Billy Shafer · Oct 25, 2015

I agree with you. Meggers are over rated. I have been working on generators since 1968. I have used a Megger twice in that time. They can be dangerous to you and equipment. If you don't know how to use them. I saw one genset fail a megger test. 30 years later it was still in operation. With no problems

Bill in IN · Oct 26, 2015

Meggers can be very useful. Hi-Pots (High Potential testers) even more so. Would you want to put 138,000 volts on an untested circuit?. This application is just a CYA exercise in my view. The lawyers and accountants are ruling the world....

Billy Shafer · Oct 26, 2015

Yes Bill I should have said on lower voltage.I agree the two are destroying everything. Pretty soon you will need a lawyer just to go to the bathroom.

dr sportster · Oct 26, 2015

Meggers are not overrated and are a must for some jobs . If you put bus duct in a high rise building and you don't megger each piece and it fails now what do you do disassemble 20 stories of bus duct to find the bad section . No you meggered each piece after installation . If you don't do this your screwed.

dr sportster · Oct 26, 2015

You are testing the insulation because I'm geussing the cable is buried in concrete and has to be chopped up if the cable fails or be abandoned in the floor. Perfect test for a megger.

Determined · Oct 26, 2015

Think of a spark plug wire.
The core may be fine and test as such with your ohmmeter.
Your ohmmeter will not give you any indication of the condition of the insulation unless it is completely worn off allowing a short to ground.
You need more voltage to check the integrity of your insulation.
This is the type of application where a megger would be used.
A Megger will show you what an ohmmeter can not.

Heyseed · Oct 28, 2015

I installed some Ditra floor heat and they require testing the cable before, during and after installing the tile or it voids the warranty. It made sense to test it before we buried it in thinset under a thousand dollars of Italian tile. Not even a rental place had one so I ended up buying one online.

John D Smith · Oct 29, 2015

Get in touch with the manufacturer. Ask questions.

Megohmmeter

J. Schwiebert

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Bill in IN

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Billy Shafer

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Bill in IN

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Billy Shafer

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dr sportster

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dr sportster

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Determined

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Heyseed

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John D Smith

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