Grounding
- Thread starter jamesdossett
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weressl
Esteemed Member
Yep, we ran into it again.don_resqcapt19 said:
The LINE side is the Guvernment side and the load is the Privat sector side. Of COURSE they behave difrently......
;^)
PS: if that difference would not exist, we would only have one ground bonding point for each service like the rest of the sane world does....
- Location
- Illinois
- Occupation
- retired electrician
David,
Don
And I am saying that a separate building is outside, so it is an outside thing.
Don
- Location
- Illinois
- Occupation
- retired electrician
David,
Don
That is a totally different concept. In those sections we are installing conductive objects in the earth and bonding them together and to the electrical grounding system. We don't have that in the case of the building grounding electrode system.
Don
peter d
Senior Member
- Location
- New England
So the bottom line is that the NEC continues to isolate grounded and grounding conductors, and will all but eliminate the use of a grounded "neutral" for anything but the service neutral.
But the utility/outside distribution world marches on without change and probably never will move away from the MGN system.
So where does that leave us? Where we've always been.
But the utility/outside distribution world marches on without change and probably never will move away from the MGN system.
So where does that leave us? Where we've always been.
tryinghard
Senior Member
- Location
- California
Just install the equipment ground conductor if it is on the load side of the service disconnect! At least the contractors side will be safe and correct.
Any current on low voltage between the utility service source and service destination will not be a hazard past the service disconnect only ahead of it.
Any current on low voltage between the utility service source and service destination will not be a hazard past the service disconnect only ahead of it.
tryinghard
Senior Member
- Location
- California
jamesdossett said:
James,
200A feeder requires a #6 cu ground wire, if your feed is 100? long your equipment ground would cost about $120.00.
You weigh it out $120.00 for a correct and safe application, one that does not intentionally install current on signal cabling.
$120.00,,, hum
M. D.
Senior Member
Well , while I'm no expert I have been reading quite a bit about objectionable current, and in my opinion ,...it is a very big issue. and changes will come . Why you ask ? We are learning everyday and People are winning in court. Money the great motivator:smile:
Again , I would not use 250.32(B)(2) by choice .
Again , I would not use 250.32(B)(2) by choice .
- Location
- Illinois
- Occupation
- retired electrician
M.D.
Don
That part I agree with..sort of. My problem is still with the code panel telling us the installation without an EGC is fine of the line side of the service, but very dangerous on the load side. It is an issue on both sides of the disconnect, and in my opinion an more serious issue on the line side. The American Waterworks Association says that at least one employee of one of there member companies gets shocked every work day because we don't use an EGC between the utility transformer and the building.
Don
M. D.
Senior Member
How do we help change the NESC? in other words can the NEC set the rules for the supply side ? I think a change is underway now , both in thinking and as demonstrated by some of the recent NEC changes we have seen , Also engineers on the supply side are becoming more informed as well , as more and more remedies are employed on the supply side and positive results are seen, it will become easier to see that changes are needed . I hate to say it but Lawsuits also play a role.
ptonsparky
Tom
- Occupation
- EC - retired
Putting that EGC from the pole to the house is going to be real interesting. Looks like a whole new feeder. Don't forget the dryer/range problem at the house. New panel. $129 extra for the new outbuilding isn't bad, but that house service is going to be a wallet getter.
Haven't quite figured out how this requirement will help any installation that has multiple 3 wire services now and we add a new building service required to be 4 wire. With a smaller EGC there may even be more of a potential problem.
Haven't quite figured out how this requirement will help any installation that has multiple 3 wire services now and we add a new building service required to be 4 wire. With a smaller EGC there may even be more of a potential problem.
tryinghard
Senior Member
- Location
- California
Options?
Options?
Could:
1) Require the installation of the equipment-grounding conductor.
2) Require the installation of current transformers on conductive items that
will shunt trip the main.
3) Require water workers, cable installers, & phone installers? to be licensed electricians.
4) Or just leave it alone and know that there is current on these conductive materials.
Options?
don_resqcapt19 said:
Could:
1) Require the installation of the equipment-grounding conductor.
2) Require the installation of current transformers on conductive items that
will shunt trip the main.
3) Require water workers, cable installers, & phone installers? to be licensed electricians.
4) Or just leave it alone and know that there is current on these conductive materials.
don_resqcapt19 said:
Equipotential bonding certainly is different than electrode grounding but it is not a different concept. . Equipotential and electrode connection to the system at multiple points both rely on the concept that multiple contacts with the earth provide near zero potential throughout the installation. . When one of your electrodes is a rebar footer, you get the surface contact of the footer to earth.
Look at what makes an equipotential grid around a pool desirable and you?ll see the reason that multi-point electrodes are desirable outside.
David
- Location
- Massachusetts
dnem said:
Electrodes, no mater how many can not ever accomplish this. That is one of the big electrical myths about grounding.
I agree with Don, different concepts entirely.
IMO the fact the code requires a grounding grid proves that the job can not be done with multiple electrodes.
tryinghard said:
What exactly is the hazard of the multi-point grounded neutral ahead of the service ? . It’s obvious that the load side of a disconnected neutral is a danger in all situations, service, feeder, or circuit. . But how does the presence of an equipment ground eliminate or even lessen that particular threat ?
How about the thought of OCPD operation ? . The only reason you need an equipment ground to operate an OCPD is because the equipment ground is bonded to everything that’s metal. . The old ranges and dryers that have their housing bonded to the neutral use the neutral to operate the OCPD. . The neutral has no problem handling the fault current and tripping the OCPD.
So what’s the hazard that exists outside ahead of the service ?
I’m not arguing for using a neutral inside for fault current. . I’m not arguing for using a neutral on any circuit for fault current. . I’m asking about services or feeders going from one separate structure to another separate structure, building to building, 250.24(A)(2) transformer to building, stuff like that.
I know that connecting the housing of an appliance to a conductor that carries normal load [ie: neutral] is not a desirable situation and it was good that the NEC stopped that years ago. . But structure to structure runs of services and feeders can use the multipoint bonded neutral for fault current without issue. . Utility pole to utility pole, utility transformer to utility transformer can use a mulitpoint grounded neutral without a problem.
Consider this: any 2 points on this planet separated by a mile or more will have different potentials. . If you run a neutral plus a fault current only conductor [equipment ground] from point A to another point which is several miles away, point B, and only ground the neutral at point A, then:
Neutral to fault current conductor voltage at point A will be zero.
Neutral to fault current conductor voltage at point B will not be zero.
So have you gained enough to justify the additional cost of the fault current conductor only in that situation ?
There's a breakoff point where having a fault current only conductor doesn't increase safety for the amount of money you would need to spend. . The utilities obviously don't think it's worth their while to run a fault current only conductor thru their distribution system [but they also often times don't think it's worthwhile to run a neutral and would rather throw their unbalanced current into the ground which is another discussion altogether].
Is it worth while over shorter distances than a mile ? . There's a breaking point somewhere.
David
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- Location
- Illinois
- Occupation
- retired electrician
David,
Don
Not really. Only at and very close to the grounding electrode(s) will be at the same potential. If you are standing on the earth 3' from the electrode you will be subjected to about 85% of the voltage difference between the electrode and remote earth. Remote earth being defined as outside the sphere of influence of the grounding electrode(s), often said to be about 50' away.
Don
tryinghard
Senior Member
- Location
- California
dnem said:
The hazard is current on non-electrical items like phone/coaxial cable.
You are trying to qualify using 250-32 (B)(2) for James? application, but 250-32 (B)(2) is only safe if ALL THREE of it?s criterion are met.
My argument is if they will be installing phone/coaxial cable from this pole to each building, at least one ? if not both ? of these systems will be bonded to electrodes at each end and with this current will ABSOLUTLY travel on them every time the neutral is used!
If these systems are installed between the pole and another building they ABSOLUTLY qualify as violating 250-32(B)(2) & #(2), in other words if these are - or maybe future - installed then you cannot use 250-32(B)(2) ONLY 250-32(B)(1)
tryinghard
Senior Member
- Location
- California
dnem said:
Actually the only purpose of an equipment-grounding conductor is to enable a low impedance path to source so in the event of a fault it will enable extremely high amperes and open the source evacuating the voltage on the non-electrical conductive items ASAP and instantaneously preferred! This is explained clearly in 250-4(A)(3)(4)&(5).
The concern is not for the neutral it is only for the bonded and conductive items to remain clear of current.
I am curious now, in your opinion what does violate 250-32(B)(2) #(2)?
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