Megger Testing

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zinsco

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San Diego, CA
How do you do a megger test on the wiring of a home?

I've heard of megger testing but for what ever reason I have never actually done one.

My customer's tree near her house was hit by lightning and the insurance company suggested that she have an electrician do a megger test on her wiring. They said they would pay for it so I told her I would go rent one and do it for her.

Now, I assume you unplug everything in the house, turn of all the breakers, connect one lead from the megger to ground, the other lead to each wire one at a time taking them off each breaker. Run the megger and see the results.

What voltage will I set the megger at and do I need to disconnect the bond from neutral to ufffer?

What results should I expect and how do I read it?

Thanks
 
I have enough experience with a megger to be dangerous. From your post you may want to consider finding someone in your area that is well versed in doing this type of work. Get their price and add a % for your time. I doubt the insurance co. would pay for any thing that may be damaged during the megger process if not done correctly. Not to mention putting you credibility on the line. Depending on your location you may find some one here.
 
Assuming all devices are in place.

Disconnect any appliances and unplug and utilization equipment.

I would either do a continuity check or megger at 50 or 100 VDC (if available on your meter) first to avoid frying any equipment with 1000 VDC.

With the power off and all safety checks made.

I would megger each circuit hot to ground, hot to neutral, hot to hot in (in a multiwire circuit), neutral to ground.

I would test for one minute each, record temperature, humidity and test voltage and megger reading.
 
wptski said:
You can't megger any circuits that have a GFCI receptacle on it without disconnecting them or the test will fail.
Click to expand...

Any devices such as GFCI, Smokes detectors, door bell transformers, make sure all light switches are off first, dryer, washer and refrigerator unplugged.
 
megger

megger

All devices must be removed from circuits including lighting. You cannot test any other way.
I just did one for someone yesterday...
Go to fluke.com look up 1587 tester. Call their tech support for more info, they will tell you same thing. meter cost about 600 bucks.
 
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