o/t Use of Megger in a Home inspection

[DHester]

Got a question that is not code related. I am trying to get a feel for how long it would take if you were to Megger a residential electrical system.

I have a basic understanding of what the test is for (Insulation test) and how it is performed. What I am trying to understand is if one was to perform this test how involved this would be.

As you can see I have never seen anyone do it so I am trying to get feel for the process.

[Jerry Peck - Codeman]

First, be careful when using a megger (place cursor over link, then right click, select 'Open in new window' http://s159.photobucket.com/user/brianj ... 7.pbw.html ).

Here is some good reading before purchasing and using a megger (place cursor over link, then right click, select 'Open in new window' http://www.transcat.com/PDF/BasicInsulationTesting.pdf ).

Here is some more reading, not the best article, but informatice nonetheless (place cursor over link, then right click, select 'Open in new window' http://ecmweb.com/test-amp-measurement/ ... ce-testing ).

Here is some more reading (place cursor over link, then right click, select 'Open in new window' http://jmtestsystems.com/PDFs/megohmmet ... esting.pdf ).

And some more reading (place cursor over link, then right click, select 'Open in new window' http://www.newark.com/pdfs/techarticles ... VCable.pdf ).

It is not something I would chose to do during a home inspection - while megohm testing is not necessarily designed to be used on NM cable, it could be, but it will be quite time consuming as all loads need to be removed from the circuits and all power needs to be removed from the circuits (remove the conductors from the breakers or you will be testing the internal workings of the breakers too, which could cause AFCI and GFCI breakers to go bad, not sure of regular breakers but if I were to presume something like that I would presume on the safe side - that regular breakers could be negatively affected too).

[DHester]

Jerry, That is what I thought. I have done some research on it before and had a basic idea of the principles involved but since I have never performed such a test and have not ever seen it performed I wanted a little real world knowledge.

I absolutely can see this used in a PM practice in a commercial setting and or an isolated evaluation of a problem circuit/motor etc...