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BONDING

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A

apauling

Senior Member
Re: BONDING

no to the 2 replies, both roger and iwire. I used the section to point out that the NEC does not consider bonding jumpers in the same conduit as the service entrance conductors (which includes the neutral when supplied) as a parallel to the neutral service entrance conductor. There is no exception or dissalowance for the neutral installation detail. The bonding wire is referred to as a jumper.

I also did not say that the use of the neutral as bond was against the code. If you actually read my first post, I said it was not the best way to do it for the reasons I stated. imho

The constraints against parallel conductors does not appear in the bonding and grounding section, but in 300, the conductors.

I am only stating my opinion that I think that the use of the neutral as bond (in this situation) is allowed, not required as it is a lesser quality of install. I think you are both defending your preference.

I would allow the mentioned install and I would allow the bonding jumper.

I would respond to the post in detail but it seems there was no intent to actually understand what i said, only to dispute it out of context.

I am not alone in this viewpoint.

if you have the handbook to the 99 NEC (many have not yet adopted the 2002NEC) the iilustration at 250.11 points out that a bonding jumper from the ko to the neutral is often required, irregardless of whether the neutral was bare and a conductor from the same point by contact, and that would definitely be a sizing problem if you wereto consider that a paralleled neutral. This is no different than bonding the meter case.

paul
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: BONDING

Originally posted by apauling:
The constraints against parallel conductors does not appear in the bonding and grounding section, but in 300, the conductors.
Click to expand...
Ah, OK, I did not understand grounding and bonding conductors where not conductors. :roll:

Scary Inspector.
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: BONDING

Paul, what you are describing would be as follows

Parallel_Neutral_and_EGC.JPG



so do you contend this is a desired wiring method?

Roger
 
A

apauling

Senior Member
Re: BONDING

without looking up the specific code sections..

No, you have drawn two GEC connections from the meter socket. If there is a GEC connection from that meter socket that ties it to the whole grounding system, there is no need for the colored jumper you have drawn. Remove the colored jumper and that is what I am advocating.

The meter socket is inaccessible and the primary GEC connections need to be accessible, so that GEC line that is drwan is actually a jumper. I AM advocating (not requiring as code allows for the grounded electrode conductor to bond the two metal service cabinets (meter socket and disconnect) that there be a connection from the two cabinets bonding them to the GEC system independently of the neutral service entrance conductor.

The real problem that I have is the use of non-continuous non-metal conduit in the service entrance path. I find no good reason for this. A continuous threaded metallic conduit would allow this jumper to be excluded.

I was reading other threads where iwire advocates that running unprotected wire conduit from the meter socket to the disconnect, or was it from the service drop to the disconnect, was legal. This has got to be rural. I have never worked in an area where this was allowed. I was always required to protect the overhead service drop from drop to disconnect in continuous metal conduit, and where that pipe connection was not secure (ko's for example) electrically, jumpers were required.

And again, I am not saying that the code disallows this bonding with the neutral, I just consider it a lesser quality install. Put in the metal conduit from socket to the disconnect, spend a few more bucks.

Is it possible that you are considering the meter as the service disconnect?

gone till tuesday (probably)

paul
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: BONDING

Originally posted by apauling:
I was reading other threads where iwire advocates that running unprotected wire conduit from the meter socket to the disconnect, or was it from the service drop to the disconnect, was legal. This has got to be rural.
Click to expand...
It was not that I was advocating it, I was just saying it was a method that is allowed in many areas. :)

My own house is an all SE service with about 3' of SE inside the basement.

Rural?

The City of Boston and the rest of MA, RI, CT? I guess if you want to call it that. :cool:

I am not saying that the code disallows this bonding with the neutral, I just consider it a lesser quality install. Put in the metal conduit from socket to the disconnect, spend a few more bucks.
Click to expand...
Paul it has nothing to do with money for me.

Since I have been coming to these forums I have learned a lot, and one thing I have decided for my own piece of mind is not to intentionally create parallel paths for neutral current if it can be avoided and remain code compliant.

To that end I will use Schedule 80 PVC between a meter socket and service panel when protection from physical damage is required and there will be no bonding jumper between them.

I consider this a better quality installation.

Paul you have never given an explanation as to how this additional bonding would add to safety?

If a fault happens in the meter socket, the fault current has a much larger bonding conductor right back to the source of the current when using the grounded conductor.

You do know that the fault current must go back to the source not to the earth?

Bob

[ April 02, 2004, 04:14 AM: Message edited by: iwire ]
 
A

apauling

Senior Member
Re: BONDING

after this I am gone. Are you saying that metal conduit from the meter socket to the disconnect is a parallel path for the neutral? please clarify and i'll be back on Tues.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: BONDING

Originally posted by apauling:
Are you saying that metal conduit from the meter socket to the disconnect is a parallel path for the neutral?
Click to expand...
Yes, most defiantly. :)

I do not know how to explain that it is a parallel path, we have gone over it a bunch of times.

How about you explain how it will not carry neutral current? :cool:

Bob
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: BONDING

Paul, Ed has shown the metalic conduit as a parallel path. Back to my earlier drawing,
you have drawn two GEC connections from the meter socket.
Click to expand...
where do you see (2) GEC's? There is only one GEC shown going out the bottom of the meter.

Can you get your hands on the spring edition of NECDIGEST? I just openned mine at work and John Caloggero addresses this very issue.


Roger

[ April 02, 2004, 04:11 PM: Message edited by: roger ]
 
E

eprice

Senior Member
Location
Utah
Re: BONDING

Originally posted by apauling:
...I AM advocating (not requiring as code allows for the grounded electrode conductor to bond the two metal service cabinets (meter socket and disconnect) that there be a connection from the two cabinets bonding them to the GEC system independently of the neutral service entrance conductor...
Click to expand...
Paul, I'm getting the impression from this post that you consider the purspose of the bonding to be to provide a current path from the cabinets to the grounding electrode system?

I believe the purpose of the bonding is to provide a low impedance path for fault current back to the source which is the utility transformer. That path will need to follow the service neutral. The quickest way to get any fault current that may occur in the meter cabinet to the service neutral and thus back to the source, is to bond it to the service neutral without using some equipment grounding conductor that passes back through the disconnect cabinet. In fact, if there is a ground fault in the meter cabinet, and if the meter cabinet is bonded to the service neutral, the service entrance neutral between meter and disconnect and the parallel (I agree with iwire on this) conduit and/or equipment ground will play no part in the fault clearing path for that current.

Maybe I'm misunderstanding you on this...
 
W

william runkle

Senior Member
Location
Michigan
Re: BONDING

This thread is getting more confusing. Does Paul want to make sure the grounded conductor become isolated? Or does he want to eliminate S.E.U. and use S.E.R. and Non Metallic Conduit from services? So all the meter cans will have to isolate the the?Grounded Conductor? If then how does the Grounded Conductor become Grounded? Have to change the definition of Grounded Conductor to Isolated Neutral Conductor. I have asked these questions to help show Paul that the Grounded conductor is bonded at the meter socket the splice is bolted directly to the can, and is bonded to the service panel. No need for a bonding bushing in the meter can or service panel unless the grounded conductor is bare.
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Re: BONDING

I think the whole idea of the requirement of bonding the neutral to the meter can and at the service disconnect/panel is because between this and the transformer there is no OCPD protection AT ALL! and if there is a fault in the service entrance cable to any of these inclosure's there will be a big ARC! requiring a #6 or even a #4 as a path for this fault would be like putting a cup of water on a house fire as this wire would evaporate into molten metal. as far as depending on the nipple between the meter and the service disconnect/panel this little contact area would just blow up into a mass of molten metal. As Bob has said the path of the neutral would be a much better path back to the transformer than a #6/4 bonding wire.
It must be understood that the fuse on the primary side of a utility transformer is not sized to protect the service drop wires! It is there to protect the primary wires and that is all! I have seen first hand what a fault on the service side can do and it is not good if the neutral fails as the whole service can burn right off the building. Remember that the available fault current can be as high or even higher than 10,000 amps+ when this fault occurs. so requiring this little jumper just don't make any sense and only will be the first conductor to blow open in a service entrance cable fault and cause more problems than it will fix.

I half to add this we run #3 or 2/0 up to the drop then the utility will sometimes run a smaller sized wire I wonder if this is the reason because this way there wire would act like a fuse and burn free before the entrance wires did, like a fuse link? I need Charlie of IPL on this one.

[ April 05, 2004, 01:00 AM: Message edited by: hurk27 ]
 
R

rasmithircgov.com

Member
Location
Florida
Re: BONDING

Paul, please remember we are inspecting code minimums, and as inspectors thats what we are required to enforce. We could what if a job to death. "Just the minimums mam just the minimums." :D
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: BONDING

Originally posted by rasmithircgov.com:
"Just the minimums mam just the minimums." :D
Click to expand...
Robert, are we going to have to address you as Mr. Friday now? ;)

Roger
 
W

websparky

Senior Member
Location
Cleveland, Ohio
Re: BONDING

Hi Guys,

Let me see if I have this straight.....

The code permits the grounded conductor to be bonded to the meter can even if there is a metalic connection via conduit between it and the service disconnect, right?

However, you are pointing out that if this is the case, you will have a parallel path for "neutral" and "fault" current, right?
 
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