Do I need a megger?

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zappy

zappy

Senior Member
Location
CA.
I got a call from a customer. They got caught doing work without a permit. The inspector told them to get a electrician to confirm that everything is safe. The inspector said it's because the sheet rock is already up. There lucky he didn't make them take all the sheet rock off!

So I should check for wire size, tight connections, properly grounded equipment, GFCI, AFCI in bedrooms. Anything else I should do? I don't own a megger. Should I get one? Can you recommend one that's a good price and easy to use? Thank you for your help.
 
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satcom

Senior Member
zappy said:
I got a call from a customer. They got caught doing work without a permit. The inspector told them to get a electrician to confirm that everything is safe. The inspector said it's because the sheet rock is already up. There lucky he didn't make them take all the sheet rock off!

So I should check for wire size, tight connections, properly grounded equipment, GFCI, AFCI in bedrooms. Anything else I should do? I don't own a megger. Should I get one? Can you recommend one that's a good price and easy to use? Thank you for your help.
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I had some pictures of dumpsters loaded with entire basement jobs, that were done without permits or inspections, they all were told the same get so electrician to say it's safe, only problem is there are not many electricians that are going to put their seal on a job, that is covered up, a megger is not a magic tool, you can have some real mess behind the walls, most people call every ec in the book, and most of them decline taking on that kind of liability.
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I suspect that the Inspector will want to see a written report that describes not only what you found, but how you went about looking for issues. If you don't include a statement that you tested for damaged insulation, they might not accept the results. I think you could rent a meggar for a reasonable fee.

I would also add one step to your inspection. Start by turning on all lights and plugging something into every receptacle in the entire house. Then turn off all breakers. Turn on one breaker at a time, and see what gets powered by that circuit. This will tell you about possible violations of the rules about no other outlets on small appliance, laundry, and bathroom receptacle circuits, possible concerns about too many outlets on a single circuit, and possible lack of AFCI protection where it is needed. As a side benefit, you can give the home owner a list of what breaker suppliles what loads.
 
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satox

Member
"Megger" .....I havent used one of those in 20 years! We had yearly station grounding checks that we needed to use the "megger" with. The cool thing was if the values you came up with were too low ... you added salt solutions to the ground stake area until you met spec!
 
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zog

zog

Senior Member
Location
Charlotte, NC
satox said:
"Megger" .....I havent used one of those in 20 years! We had yearly station grounding checks that we needed to use the "megger" with. The cool thing was if the values you came up with were too low ... you added salt solutions to the ground stake area until you met spec!
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You don't use a megger to measure ground resistance, the results are meaningless. You use a 3 or 4 point fall of potential test set.

Adding a salt solution would reduce the values, not raise them, and it is a temperory fix until the next good rainfall so not an acceptable method of meeting a certain spec for your ground resistance.
 
growler

growler

Senior Member
Location
Atlanta,GA
zappy said:
I got a call from a customer. They got caught doing work without a permit. The inspector told them to get a electrician to confirm that everything is safe. The inspector said it's because the sheet rock is already up. There lucky he didn't make them take all the sheet rock off!
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A homeowner can pull a permit for a job like this so what they want is an EC that's dumb enough to take the responsibility and liability for someone else's work that probably has no idea what they are doing.

I would be very carefull about getting involved. First you will need to know who did the work and then get an idea of how much they know about electrical. Then you will want to pull some of the sheetrock to see it the wiring looks OK. If they did the random samples right then the rest may be OK. Many times those working without permits are not doing a real good job because they know the work will be hidden and so it's fast and cheap.


If you pull some of the rock and find they didn't drill their holes 1 1/4 from the edge of the stud or didn't use nail guards that should tell you something. Give things a good visual first and look for signs that it all crap work. Most of these jobs I wouldn't touch with a ten foot pole short of a complete rewire.
 
W

wireguru

Senior Member
i wouldnt touch it without exposing every inch of wire. Why should you put your license and livelyhood on the line to save a cheap homeowner a few bucks? They cut corners and now they have to pay the price. Who knows whats going on behind those walls. Could be scraps of romex soldered and taped together for all you know. If it was done right it would have been permitted.
 
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SEO

Senior Member
Location
Michigan
Anybody that would sign their name on a project that they did not look at is taking a great risk. They may be liable for future damages and or injury resulting from the unseen installation.

There may be open splices, cords spliced to nm cable, nail plates not installed where required, no draft stopping where required, nm cable installed in cold air returns, staples driven in to far the list could go on and on.

I see this kind of stuff on rough inspections where people are trying to do it right and do have it inspected.
 
Split Bolt

Split Bolt

Senior Member
Location
Northern Virginia
IMHO, NEVER stick your neck out by putting your reputation on the line for somebody else! Every now and then, I'll get a call from a homeowner who did all of his wiring and left tails of romex hanging at the panel. "How much would you charge me to hook the circuits up to breakers? I don't feel confident enough to do that part of the job!" I just tell them I'm sorry I can't help them, but I'm a licensed master electrician, which means I know better! Then I politely tell them "good luck with that!":D
 
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dbuckley

Senior Member
Location
Canterbury, New Zealand
Rewire said:
What would you regularly use one for?
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Before I apply power to a circuit, I megger it to make sure its a safe circuit to energize. Yes, every circuit. If it leaks, I need to know why, so someone doesn't get shocked sometime down the line, or we dont end up with a fire on our hands.

Whereas AFCIs and GFCIs stop the worst excesses (generating what people call nusiance trips), its almost impossible to open a breaker this side of putting a spanner betwixt hot and N.
 
Rewire

Rewire

Senior Member
Location
Lake of the Ozarks
dbuckley said:
Before I apply power to a circuit, I megger it to make sure its a safe circuit to energize. Yes, every circuit. If it leaks, I need to know why, so someone doesn't get shocked sometime down the line, or we dont end up with a fire on our hands.

Whereas AFCIs and GFCIs stop the worst excesses (generating what people call nusiance trips), its almost impossible to open a breaker this side of putting a spanner betwixt hot and N.
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On a properly grounded circuit a "leak" should trip the breraker.
 
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satcom

Senior Member
Rewire said:
On a properly grounded circuit a "leak" should trip the breraker.
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Some breakers are not designed to trip on many conditions, some of the old style thermal breakers would not trip.

At one time, electrician used a megger before they powered up, and you may still find some wiring prints and megger readings taken on those completed homes wiring, and it had the electricians name on it, fat chance of finding that in todays homes, your lucky to remember anything about the guys wiring the home, expect he had loud music playing, and left a mess when they left, the true craft workers are gone, replaced by an army of ax and knife, just do it guys.
 
ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
conductor to conductor, conductor to grnd. Make sure you have no loads, gfci or dimmers. Isolate from EG and neutral bars. all connections at jbox etc must be made up.
b-w
b-g
w-g
connect wires to N & EG bars after each test. Check each new circuit neutral to previously tested neutrals at bussbar. They should be open, if not you have neutrals tied together someplace. Check new circuit hot to neutral bar etc and repeat as needed.
 
Rewire

Rewire

Senior Member
Location
Lake of the Ozarks
ptonsparky said:
conductor to conductor, conductor to grnd. Make sure you have no loads, gfci or dimmers. Isolate from EG and neutral bars. all connections at jbox etc must be made up.
b-w
b-g
w-g
connect wires to N & EG bars after each test. Check each new circuit neutral to previously tested neutrals at bussbar. They should be open, if not you have neutrals tied together someplace. Check new circuit hot to neutral bar etc and repeat as needed.
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I have my fluke 1507 out i just tested a ten foot piece of romex I then gouged the wire with my strippers and I then tested again , results were the same.
 
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