field inspector

[augie47]

can't answer that one ....

can't answer that one ....

Mike Kelly-- Check your private messages...

As far as an inspector not passing of failing on site.. I think this is a commendable move. One only has to read here for a few days to realize the complexity of some issues. Not to brag on myself, and to some this obviously is a "flaw", but I fairly often ask the contractor/electricain to allow me to research something rather than "shoot from the hip". Depending on the pressure on the job, I may allow something questionable with the understanding that after reserch we might need to address that issue.
That's me.... the good/bad & definitely ugly.

 

[infinity]

Whoops there goes another would be contributing member.

ease up a little guys Mike is here to learn

I agree with MD, let's keep with the subject matter. We can exchange the other "stuff" through private messages.

 

[M. D.]

Here when the inspector leaves i either passed or got a tag.I never had one say i will let you know later after i read up on it..........

In Massachusetts , where the motto ought to be , "we regulate regularly" the inspectors have 5 days from the date of receiving notice of completion , to " think about it " Perhaps more inspectors should take some time to "think about it " ,...Perhaps that is what Mike is doing now..

CH 143 3L
Any person installing for hire electrical wiring or fixtures subject to this section shall notify the inspector of wires in writing upon the completion of the work. The inspector of wires shall, within five days of such notification, give written notice of his approval or disapproval of said work. A notice of disapproval shall contain specifications of the part of the work disapproved, together with a reference to the rule or regulation of the board of fire prevention regulations which has been violated.

 

[steelersman]

I performed a residential electrical sub-panel addition in a garage. The h/o did the work and wired the sub-panel with the white conductor(s) and the bare ground conductor(s) together on the isolated neutral bar. I tested the outlets for GFCI and it proved to work well.

What would happen if there was a ground fault?

What would happen if there was an open neutral?

Does the GFCI need a equipment ground to properly function?

I truly believe this is a troll post trying to get a rise out of some folks on here.

 

[M. D.]

I truly believe this is a troll post trying to get a rise out of some folks on here.

And I thought I had time on my hands:roll:

 

[wbalsam1]

Whoops there goes another would be contributing member.

ease up a little guys Mike is here to learn

I sure hope my comments were not taken out of context. I absolutely did not direct my comments about poor inspections to the poster or anyone else on this forum. I'm only relating personal experience, that's all.

I welcome all new members all the while realizing what a truly wonderful site this is. :smile:

 

[resistance]

Welcome to the future.

You are in cali, so it's never going to change.....:grin:

I wouldn't hesitate to believe the OP is an HO doing his own work. Yet, I could be wrong, if I am, then slap me

 

[Jim W in Tampa]

If we had to wait 5 days our jobs would be held up.5 days is a joke.Either the inspector is qualified or he is not.When you take the test to be a master you dont get 5 days,not even 5 hours.Your costing money with a delay like that.Just what is it that would take more than 1 day ?

 

[Dennis Alwon]

I agree that 5 days is too long to wait however I have never had that situation. Look at it this way--- Have you ever asked a question on this forum that you did not know the answer to??? If you did then the same argument can be said about you--- are you qualified? It is impossible to know everything and you all know many EC don't know squat-- relatively speaking-- myself included.

All I am saying is we don't know the situation. Towns may need to hire new guys and train them as they go-- unfortunate- yes but ever electrician got trained as they went and made many a mistake on the way also. Let's not be so quick to assume the negative.

 

[barbeer]

As far as an inspector not passing of failing on site.. I think this is a commendable move. One only has to read here for a few days to realize the complexity of some issues. Not to brag on myself, and to some this obviously is a "flaw", but I fairly often ask the contractor/electricain to allow me to research something rather than "shoot from the hip". Depending on the pressure on the job, I may allow something questionable with the understanding that after reserch we might need to address that issue.
That's me.... the good/bad & definitely ugly.

And the inspectors that do not operate this way (^^^) are the one's that have all these guys b****ing but they still complain!? I fully agree, it is a big book and when you go from a house to a hospital to a fuel station thoughts can be tangled.

 

[gar]

080806-1554 EST

mikekelly:

First, the subpanel is wired wrong as has been stated.

Second, to answer your questions, and a couple more.

Let's assume we have only a 0-120 subpanel, no 240.

How does a GFCI work?

Internally there is no connection of the EGC terminal to any of the GFCI components. Thus, other than for an external tester the EGC terminal and EGC sockets have nothing to do with the GFCI operation.

Internal to the GFCI the hot and neutral conductors pass thru a current transformer. If there is no external shunt path or current source on the load side of the current transformer, then the current transformer output is zero because the neutral and hot conductor currents are exactly equal but of opposite direction and their magnetic fields cancel.

If you unbalance these currents by approximately 5 MA, then a threshold detector will trip the GFCI device. There is filtering on the threshold operation so larger currents cause quicker tripping.

An aside. If I apply a DC unbalance of a reasonable value the GFCI will not trip. In other words considerably above the nominal 5 MA threshold. A dangerous condition that would not cause a trip is: charging a 120 V battery with the negative terminal of the battery connected to neutral, and a short from +120 V to EGC thru your body.

A basic understanding of how GFCI devices work and electrical theory provides a means to answer your questions. I suggest you take one apart and study its construction and operation.

I believe your circuit has neutral and EGC connected together at the subpanel, but isolated from the panel. Assume nothing connects to the subpanel enclosure. Also nowhere beyond the subpanel is there any connection between the EGC and neutral.

What would happen if there was a ground fault?

An adequate conductive path from hot or neutral on the load side of the GFCI to EGC will trip the GFCI. If the short was from neutral to EGC, then there needs to be some load to cause unbalanced current flow.

Anything that will cause an unbalanced current thru the current transformer that exceeds the threshold will trip the GFCI. If I have a 500 V AC supply somewhere and referenced to earth anywhere or in the case of neutral before the GFCI and an appropriate resistor from the 500 V to either the load side neutral or hot wire will trip the GFCI.l

What would happen if there was a an open neutral?

An open neutral to a GFCI receptacle will deprive the GFCI of power to trip the GFCI. Thus, a short of a GFCI output hot line to EGC will not trip the GFCI. Nothing else will trip the device except the TEST button (Leviton device I analyzed). Loss of neutral after the GFCI (on the load side) will deprive the load of power. Nothing will happen until something causes an unbalanced current thru the GFCI, and then it will trip.

Does the GFCI need a equipment ground to properly function?

No. If by that you mean will an unbalanced current thru the current transformer cause the GFCI to trip. This of course requires input power to neutral and hot of the GFCI.


The Leviton can not be RESET (circuit closed and latched) if there is no neutral-hot input power. The TEST button only mechanically trips the latch and I do not call that a test. However, on pushing the RESET button a test is performed and if this is not successful, then the GFCI contacts do not close, and you can not latch the GFCI. You must have input power to RESET and latch the GFCI. Connecting the input neutral and hot to the ouput terminals will not allow you to RESET and latch the GFCI.

If you latch the GFCI, requires correctly connected power and pushing the RESET button, then remove power the latch will remain latched. Now disconnect the power source, switch the power leads to the output terminals, and you will get power flow thru the GFCI. An unbalanced current should trip the GFCI. I have not tested this. Once tripped it would not be possible to RESET the GFCI.

My above assumption that the subpanel enclosure is floating, not connected to anything, means if you short the hot output of a GFCI receptacle to the enclosure that may not trip the GFCI. It will make the subpanel enclosure dangerous.

See my posts 162 and 171 an evolution in analysis at
http://forums.mikeholt.com/showthread.php?t=102022&page=5

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