New houses. Do you test the circuits "Megger"

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acrwc10

acrwc10

Master Code Professional
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CA
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Building inspector
Just out of curiosity on residential work, with the need for AFCI's , does anybody megger the circuit before drywall just to be sure they are clear of faults or do you wait until a problem shows up? (tripping AFCI) Then trouble shoot the issue.
 
With the housing crash, who's doing new houses, and can they even afford a megger these days?
Dies_Laughing_emoticon.gif


But the remodels, additions & basement finishes I'm up to my gills with these days, yes.... my new 1507 gets used.
 
thats actually a pretty good idea. if the house is wired with afci's everywhere then using a megger is a good idea. just tie the wires together with wirenuts and megger the homerun. shouldnt take longer than a few minutes to wirenut wires together. just to make sure you dont have any shorts before. if any shows up someones going to pay:smile: the boss frowns upon using a megger so i dont know how thats going to work out
 
we dont meg I dont even know if we have a megger in the company. What I have done in the past when I know Its an area I will never be able to access again is Ill hook some temp power and make sure all boxes have power. We did this one time with a group of canlights on a church Knew we couldnt get back to them Really should meg but using my bosses mentality we just dont have the time theres always the next house to get to
 
billdozier said:
we dont meg I dont even know if we have a megger in the company. What I have done in the past when I know Its an area I will never be able to access again is Ill hook some temp power and make sure all boxes have power. We did this one time with a group of canlights on a church Knew we couldnt get back to them Really should meg but using my bosses mentality we just dont have the time theres always the next house to get to
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That is not going to show a nick in the insulation that may appear later on as a fault, I know this from experience. A Megger test takes no more time then what you did with a temp cord and is a lot more accurate.
 
acrwc10 said:
That is not going to show a nick in the insulation that may appear later on as a fault, I know this from experience. A Megger test takes no more time then what you did with a temp cord and is a lot more accurate.
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It still might not find every problem, since you'll be manipulating the conductors when you put devices on, but it sure can't hurt.

For those who add circuits to mobile and modular homes, and rewire (in whole or in part) mobile and modular homes, the code requires you to megger the completed circuits.
 
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acrwc10 said:
Just out of curiosity on residential work, with the need for AFCI's , does anybody megger the circuit before drywall just to be sure they are clear of faults or do you wait until a problem shows up? (tripping AFCI) Then trouble shoot the issue.
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I have never thought of doing that before but if I wire a new house I am going to. I just need to buy a megger first. :)
 
Several years ago I bid a set of blue prints for a house that had written in the specs. that all circuits be Megger tested. I laughed at the spec and thought to my self why waste the time? Now I feel very differently about the subject after seeing just how many "hidden" faults there can be after sheet-rock, faults that don't show up on a regular ohm meter and are intermittent in faulting.
 
All of the addition/remodels I wire is me being the one to oversee the project(s). I have never meggered anything, I dont even own one of those things.
That said, I see where doing so would benifit the job. Im just so used to doing it ,, ummm, errr,, the old fashioned way?
 
Pierre C Belarge said:
110.7 Wiring Integrity.
Completed wiring installations shall be free from short circuits. Ground faults, or any connections to ground other than as required or permitted elsewhere in this Code.
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Doesn't mean you have to meg it.

What I use to do was megger and show the GC, if there was an issue later it fell on someone eles's shoulders (I ALWAYS THOUGHT).

With busway I did it as I received the bus, as each piece went up and the now partially completed run then the completed run. Then when water got in the bus it WAS on someone else.
 
steelersman said:
now there's one I think I knew without any help from the NEC. Seems like common sense.
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Seems like it , but how many times have you gone on a service call and found a ground/bond being used as a neutral ?
 
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acrwc10 said:
steelersman said:
now there's one I think I knew without any help from the NEC. Seems like common sense.
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Seems like it , but how many times have you gone on a service call and found a ground/bond being used as a neutral ?
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I dont have a count, but I have seen this in some trouble calls. It seemed as though instead of finding where the heutral had come loose the person would just tap off of the ground.
That can be deadly.
I remember a trouble call once where the tennants called the POCO first. I forget the original problem, but I went outside to check the sevice and found the ground clamp to be damaged and loose and went to start fixing it. I then got the crap knocked out of me. Come to find out the neutral connection had broke loose up at the pole and the service was trying to use the ground as the neutral.
 
aftershock said:
I dont have a count, but I have seen this in some trouble calls. It seemed as though instead of finding where the heutral had come loose the person would just tap off of the ground.
That can be deadly.
I remember a trouble call once where the tennants called the POCO first. I forget the original problem, but I went outside to check the sevice and found the ground clamp to be damaged and loose and went to start fixing it. I then got the crap knocked out of me. Come to find out the neutral connection had broke loose up at the pole and the service was trying to use the ground as the neutral.
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OUCH, I'll bet you haven't made that mistake twice.
 
aftershock said:
I remember a trouble call once where the tennants called the POCO first. I forget the original problem, but I went outside to check the sevice and found the ground clamp to be damaged and loose and went to start fixing it. I then got the crap knocked out of me. Come to find out the neutral connection had broke loose up at the pole and the service was trying to use the ground as the neutral.
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That can happen without a 110.7 violation. A loose service neutral with a properly installed grounding electrode system will always do that - Ohms Law.
 
George Stolz said:
That can happen without a 110.7 violation. A loose service neutral with a properly installed grounding electrode system will always do that - Ohms Law.
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The same can also happen if there is no isolation at the water metering - the metalic water line becomes a parallel path via the nieghbors house.
 
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