- Location
- Massachusetts
Gmack said:
Now wait a minute.
Undersized EGCs or properly sized EGCs?
Under sized EGCs are already an NEC violation.
EGCs need not be as large as the circuit conductors to be effective.
grounding at detached garage
- Thread starter careco1
- Start date
- Status
Now wait a minute.
Undersized EGCs or properly sized EGCs?
Under sized EGCs are already an NEC violation.
EGCs need not be as large as the circuit conductors to be effective.
iwire said:
Minimum sized EGC's are properly sized but are not as large as full sized GC's.
Thats what I mean.
A #8 copper minimum is properly sized as per 250.122.
Will it do the same job as a #3 GC at tripping the OCPD's?
Upstream and down. On a sevice or feeder? Or branch?
I dont think so. It cant.
- Location
- Illinois
- Occupation
- retired electrician
That can't really be a problem as this exact parallel path is require by code rules for services.
Don
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Yes, sorry.kevin said:
stickboy1375
Senior Member
- Location
- Litchfield, CT
roger said:
Can't be any different than a POCO losing a ungrounded conductor... I just feel that everyone here has a different opinion and no hard facts to support it... (as far as running 3 vs. 4 wires to a remote panel)
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- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
No, it's not. Read 250.32(B)(1):Gmack said:
The neutral is not to be connected to the EGC or to the GES at the remote structure, when the feeder includes an EGC.
So, I ask again:
georgestolz said:
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Imagine a feeder with an EGC installed to a building, that is sized as large as the neutral in the feeder.stickboy1375 said:
The EGC in question would clear faults equally as fast.
So, would you say it's equal? I wouldn't. The four-wire has an advantage.
If the neutral opens under normal operations (as in, no faults), then none of the metal connected to the electrical system would be energized.
In the three-wire scenario, all the exposed metal would become energized, because the neutral is connected to the EGCs at the sub-panel. All that unbalanced current is trying to find it's way back to the transformer. It will find paths through people to get back, if the opportunity presents itself.
In my mind, that's about the only advantage. But, neutrals open infrequently, IMO, so it is a small advantage. I've never heard of a fatality from an open neutral, either. But the theory is sound.
- Location
- Illinois
- Occupation
- retired electrician
George,
Don
Again that can't be a real safety problem because that is how we install all of our services, and I have seen a lot more open neutrals on the line side of the service disconnect than on a feeder circuit.
Don
jwelectric
Senior Member
- Location
- North Carolina
don_resqcapt19 said:
stickboy1375 said:
Are you saying that an open neutral is not a safety problem at the service?
Or
Are you saying that because that it is a safety problem at the main it is okay to have the same safety problem elsewhere in the system?
This sounds like the soldier that was looking for a Section 8. He keep telling his CO that the reason that he didn?t want to take the point because there was only one sniper out there and he wanted two or more to shoot at him at the same time or he wouldn?t take the point.
How many different discussions have we had about installing a Main Lug panel in the detached garage?
This main lug panel is fed with a three wire feeder and the bonding is not complete what will facilitate the opening of the overcurrent devices in the remote building?
ATTENTION INSPECTOR MEMBERS; How many main lug panels do you see that are not bonded in the remote buildings?
Before the point of attachment there isn?t much that the NEC can do about the ?open neutral? or any other safety issue but after the point of attachment the NEC rules apply. The idea is to have only one point on the system where this ?floating neutral? syndrome can occur, at the main.
I am glad to see that the 2008, to date, mandates the installation of the equipment grounding conductor and compliance to all of Part III instead of just 250.50.
This will help stop the installation of main lug panels that are not bonding the equipment grounding conductors for the branch circuits back to the source.
The are many electricians as well as inspectors that can?t understand the bonding requirements of the main lug panel at a remote building such as a detached garage as they are taught in the beginning that these panels do not bond the grounded and grounding together.
Then there are some that believe that when the equipment grounding is installed with the feeders that it is to land in the same terminal bar as the grounded (neutral) in the remote panel. Their thoughts are that this main lug panel is treated as service equipment and the equipment grounding conductor is to land with the grounded (neutral) at the service equipment.
They end up running the equipment grounding and the grounded (neutral) conductors in parallel and then no bonding jumper thus the equipment grounding conductors for the branch circuits in the main lug panel are not bonded back to the source.
In my ?opinion? the 2008 cycle takes out all of the guess work and makes it a lot simpler and safer.
- Location
- Massachusetts
Mike I have no idea whatsoever how you managed to drag in the MLO panel discussion here.
This 250.32(B) discussion applies equally to MLO as MB panels.
How would a change in 250.32(B) have an effect on your pet peeve of MLO panels in separate buildings?
As far as people not understanding bonding and grounding.....of course lets 'dumb down' the NEC so even the simplest of pinheads can get it.
This 250.32(B) discussion applies equally to MLO as MB panels.
How would a change in 250.32(B) have an effect on your pet peeve of MLO panels in separate buildings?
As far as people not understanding bonding and grounding.....of course lets 'dumb down' the NEC so even the simplest of pinheads can get it.
- Location
- Illinois
- Occupation
- retired electrician
Mike,
[FONT="]All I am saying is that the code is telling us that the conditions that are required for services is a hazard at a second building. It those conditions are really a hazard, they present the same hazard at both locations and the code rules need to be the same for both locations. The parallel paths the are a hazard at the second building are required to be created by the code rules at services. Also, in my experience and opinion, there are many more open neutral conditions that occur on the line side of the service disconnect than on the load side of it.
When the code tells us that the electrons change their behavior based on who owns them, I really begin to question the technical competence of the code.
This is a lot like the rule that requires a marker tape above service conductors that are trenched in, but does not require a maker tape for the same conductors installed in the same location using directional boring. The hazard of a future dig-in does not change based on the installation method, but the code is telling us that it does.
Don
[/FONT]
[FONT="]All I am saying is that the code is telling us that the conditions that are required for services is a hazard at a second building. It those conditions are really a hazard, they present the same hazard at both locations and the code rules need to be the same for both locations. The parallel paths the are a hazard at the second building are required to be created by the code rules at services. Also, in my experience and opinion, there are many more open neutral conditions that occur on the line side of the service disconnect than on the load side of it.
When the code tells us that the electrons change their behavior based on who owns them, I really begin to question the technical competence of the code.
This is a lot like the rule that requires a marker tape above service conductors that are trenched in, but does not require a maker tape for the same conductors installed in the same location using directional boring. The hazard of a future dig-in does not change based on the installation method, but the code is telling us that it does.
Don
[/FONT]
georgestolz said:
You didnt read or hear.
Your 4 wire GC and EGC are connected back at building #1.
An open neutral at building #1 will place building #1 and #2 with potential/ "floating neutral" syndrome.
Why George, listen this time, your EGC connected at #1 building is connected to your EGC bus at #2 building and all its branch EGC's and interior metal piping and all the rest of its GES.
Don is right. We dont have open neutrals "much" in panels [busbars some, yes] But not many main lugs.
But I have had to troubleshoot a boatload on the line side of a service. And a hell breaks loose when that happens. If you havent been there, well then you wont understand.
But your "thesis" on building #2 is in error.
Now as to your "very dangerous" question. "Why be concerned aboult a fault on a GES"
Think on this.
All interior metal water piping exposed can and is used [in other than residential which is still used also within 5 ft of meter], for/as part of GES.
Last time I looked interior metal water piping is part of a GES as per NEC.
It can and will become energized and as electricians we bond and jumper so that "FAULT CURRENT" on the GES will trip OCPD's.
THAT! is why Im concerned George.
You should be too. Your presumption in all of this discussion isnt based on experience. Quit "mis" quoting the NEC.
You got a long way to go yet.
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stickboy1375
Senior Member
- Location
- Litchfield, CT
roger said:
Sorry you have to wait till monday.... have to make call to state inspector...wanna make sure I get it from the horses mouth :>
stickboy1375
Senior Member
- Location
- Litchfield, CT
jwelectric said:
I don't install main lug panels in remote buildings, they are always main breaker, fed from a 3 wire... with the ungrounded conductor bonded to the ground.... as if it were a seperate service...
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Really? (Sarcasm)Gmack said:
An open neutral at the service is not relevant to our discussion, except for comparison purposes. The question was, "What is the advantage of a three wire feeder over a feeder w/EGC?" If the service neutral at building 1 opens, everybody's screwed anyway.
Gmack, my patience with your "you're an ignorant punk kid" comments is wearing thin. So, I will counter with a picture, maybe we're just not on the same page. Please, explain to me how this open neutral ahead of building #2 will energize the exposed metals connected to the electrical system.
Let's get this aspect settled, and we'll return to the other issue.
- Location
- Illinois
- Occupation
- retired electrician
George,
That drawing appears to show the grounded conductor connected to the grounding conductor at two points in violation of the code rules.
Don
That drawing appears to show the grounded conductor connected to the grounding conductor at two points in violation of the code rules.
Don
- Location
- Illinois
- Occupation
- retired electrician
careco1,
Don
They are correct, if the concrete is not in direct contact with the earth, you can't use the re-bar as a grounding electrode.
As far as a main, 225.30 requires a disconnect for the second building, and a main is the easiest way to do this.
Don
- Status