New houses. Do you test the circuits "Megger"

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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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So true. There are a few streets around here though that no longer have an earth connection at the pole-mounted transformers. The GEC seems to be missing down aroung vandal/thief height!
 
Volta said:
So true. There are a few streets around here though that no longer have an earth connection at the pole-mounted transformers. The GEC seems to be missing down aroung vandal/thief height!
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I brought this up with a few guys from the POCO here (PG&E) who mentioned that the transformer is grounded by every building on it. This is in a densely populated city - so there is an electrode of some type every 25' or so on the grounded conductor... ;) So that said - they rarely install a ground anymore at the pole. (Not saying I agree with the practice.)

Dangerously, sometimes that all that saves the 120v equipment.
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I once went to a service call where my client was trying to blame all of his burnt crap on the neighbors plumber... :rolleyes: The sole path of his grounded connection was through his water line and through his neighbors service. The plumber got bit taking the water line apart, and my client after seeing the smoke went looking for the nearest construction type looking person because "he must of done something". :rolleyes: Called me to prove it! Too bad - and it took a lot explaining to even partialy convince him that "worked fine until he showed up" is not always the case.
 
ON a new job....can't say I have ever done it. While I dont wire homes anymore I can promise you I don't know any electricians who would look me in the eye and say they megger the wiring in the house....Might be something that should be done, but not something that is being done.
 
radiopet said:
ON a new job....can't say I have ever done it. While I dont wire homes anymore I can promise you I don't know any electricians who would look me in the eye and say they megger the wiring in the house....Might be something that should be done, but not something that is being done.
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I think you nailed it ! I think you would be in for a surprise if you started asking electricians at the supply house or on the job if they can tell you what a megger is or how one should use it. I hope I'm not beginning to sound like Marc :D
 
acrwc10 said:
I think you nailed it ! I think you would be in for a surprise if you started asking electricians at the supply house or on the job if they can tell you what a megger is or how one should use it. I hope I'm not beginning to sound like Marc :D
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I honestly have never used one, or would know how to use one, or even know if I can pick one up at my local supply house. I don't think I've ever even seen one.
 
acrwc10 said:
I think you nailed it ! I think you would be in for a surprise if you started asking electricians at the supply house or on the job if they can tell you what a megger is or how one should use it. I hope I'm not beginning to sound like Marc :D
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lol...I did have to do a double take lookie again at your username...I thought it WAS marc making the comments...lol
 
radiopet said:
lol...I did have to do a double take lookie again at your username...I thought it WAS marc making the comments...lol
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We utilize meggers extensively, I did megger branch circuits when I did that type of work. Today the only time I megger branch circuits is when we are chasing neutral grounds in a building and when we are hired by an EC to comply with a spec.

While meggering is a good idea

I'd bet
99% of electricians do not have access to a megger.
99% of men with a megger in their truck do not megger branch circuits.
50% of men with a megger in the truck do not megger feeders regularly unless reminded of the importance of meggering by their supervisors.
50% of the meggers in trucks do not work and 25% have electricians that have meggers do not know how to work the megger.
Of the small percentage that do megger regularly a fair number have no idea what the results mean.

Which falls on the training and standards more than the employees.
 
brian john said:
We utilize meggers extensively, I did megger branch circuits when I did that type of work. Today the only time I megger branch circuits is when we are chasing neutral grounds in a building and when we are hired by an EC to comply with a spec.

While meggering is a good idea

I'd bet
99% of electricians do not have access to a megger.
99% of men with a megger in their truck do not megger branch circuits.
50% of men with a megger in the truck do not megger feeders regularly unless reminded of the importance of meggering by their supervisors.
50% of the meggers in trucks do not work and 25% have electricians that have meggers do not know how to work the megger.
Of the small percentage that do megger regularly a fair number have no idea what the results mean.

Which falls on the training and standards more than the employees.
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I will agree with those figures.....;)
 
brian john said:
We utilize meggers extensively, I did megger branch circuits when I did that type of work. Today the only time I megger branch circuits is when we are chasing neutral grounds in a building and when we are hired by an EC to comply with a spec.

While meggering is a good idea

I'd bet
99% of electricians do not have access to a megger.
99% of men with a megger in their truck do not megger branch circuits.
50% of men with a megger in the truck do not megger feeders regularly unless reminded of the importance of meggering by their supervisors.
50% of the meggers in trucks do not work and 25% have electricians that have meggers do not know how to work the megger.
Of the small percentage that do megger regularly a fair number have no idea what the results mean.

Which falls on the training and standards more than the employees.
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I'm waiting for Home Depot to come out with a megging book......
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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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Never done it! Don't see a reason why i should start!

Thank goodness our state booted the AFCI requirement per NEC 2008!
 
wptski said:
That article is for motors really. It's really hard to find any specs at all for cables. Even harder to find anything at all about insulation testing of NM!
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Testing NM with a megger is about the easiest test to run with a megger.
 
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