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Thread: Grounding electrode conductor
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10-08-2009, 07:04 PM #1
Grounding electrode conductor
The Grounding electrode conductor is contacting the aluminum grounded conductor. Other than the dissimilar metals, is this an issue. The GEC runs through the utility room wall, exposed.
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10-08-2009, 08:32 PM #2
Re: Grounding electrode conductor
It looks like the neutrals and grounds are secured under the same terminal bar which makes that panel the service equipment, non- sub panel, main panel thingy
If that's the case, everything is inter- connected anyways, so I don't see it as a problem.
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10-09-2009, 07:42 AM #3
Re: Grounding electrode conductor
Thanks
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10-09-2009, 12:18 PM #4
Re: Grounding electrode conductor
There is a meter on the exterior wall.
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10-09-2009, 12:18 PM #5
Re: Grounding electrode conductor
Same thing I was wondering, does the grounding electrode conductor "follow the surface"?
From the 2008 NEC. (underlining and bold are mine)
- 250.64 Grounding Electrode Conductor Installation.
- - Grounding electrode conductors at the service, at each building or structure where supplied by a feeder(s) or branch circuit(s), or at a separately derived system shall be installed as specified in 250.64(A) through (F).
- - - (B) Securing and Protection Against Physical Damage. Where exposed, a grounding electrode conductor or its enclosure shall be securely fastened to the surface on which it is carried. A 4 AWG or larger copper or aluminum grounding electrode conductor shall be protected where exposed to physical damage. A 6 AWG grounding electrode conductor that is free from exposure to physical damage shall be permitted to be run along the surface of the building construction without metal covering or protection where it is securely fastened to the construction; otherwise, it shall be in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or cable armor. Grounding electrode conductors smaller than 6 AWG shall be in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or cable armor.
Interesting that 4-wire SER is being used.
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10-09-2009, 12:19 PM #6
Re: Grounding electrode conductor
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10-09-2009, 02:16 PM #7
Re: Grounding electrode conductor
No it is run through the studs. You can see it in this photo.
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10-09-2009, 02:32 PM #8
Re: Grounding electrode conductor
Mat,
I would recommend they either close that wall in for those stud spaces where that grounding electrode conductor is run (making them into enclosed stud cavities) or nail a protective runner board along the wall protecting it. Those two choices would be much easier than trying to put conduit around it at this point.
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10-09-2009, 03:39 PM #9
Re: Grounding electrode conductor
No problem. I would have more of a problem with the circuit grounds and neutrals sharing taps.
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10-12-2009, 06:26 AM #10
Re: Grounding electrode conductor
is that conductor a #6 or a #4 ? Need to know that before passing judgement. Just because it goes to a ground rod does not mean it a # 6.
I know of contractors that only carry #4 and use it for water and rods.
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10-12-2009, 07:31 AM #11
Re: Grounding electrode conductor
Dissimilar metals in contact can oxidize which in turn could create a problem. I would have an electrician form the conductors away from each other so as to remedy that issue.
- Another issue might be the 4-conductor SER feeding the panel. If this panel includes the service overcurrent protective device, then it should have been fed with 3-wire SEC, not 4-wire SER. The 4th wire which was intended at time of manufacture to serve as an equipment grounding conductor, is now in parallel with the grounded conductor, which is a violation of code.
My guess is that the "electrician" used 4-wire cable in place of 3-wire for the service conductors, and figured "what the heck, might as well tie this 4th wire in, too". Common mistake. But a mistake/violation, none-the-less.
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10-12-2009, 07:54 AM #12
Re: Grounding electrode conductor
Fred,
I am apparently missing something here. I know that the service entrances conductors are typically run as 3 conductors, 2-ungrounded conductors and 1-grounded conductor, but I don't recall a prohibition against running a ground wire with it - do you have the code on that? I know that "could" cause a problem (as I stated in my post a few days ago above) if the neutral were to have a bad or open connection - put is it prohibited?
If, in fact, the panel does not contain the service disconnect, then the equipment grounding conductors must be placed on an equipment grounding bar, the bonding screw removed from the neutral bus, and the grounding electrode conductor relocated to originate in the service equipment.
The other question which arises is the service cable is runs in what looks to be a conduit and not clamped to the enclosure.
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10-12-2009, 10:01 AM #13
Re: Grounding electrode conductor
Hi Jerry: Since all of the conductors in the SER must be considered conductors contained in the same cable and of the same circuit as per 300.4, then the EGC is not being used as a Grounded Conductor, therefore it isn't governed by parallel conductor rules,(not a parallel neutral) but rather by EGC rules found at 250.130. This section states (250.130(A)) that this connection shall be made by bonding the EGC to the Grounded Service Conductor AND the Grounding Electrode Conductor. It would seem unusual to have this identical condition in both the metering enclosure and the service disconnecting means if they are in separate enclosures. (Not saying it hasn't been done countless times over the years) but certainly redundant. So, I guess each condition where this appears would best be evaluated on its own individual merits.
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10-12-2009, 11:29 AM #14
Re: Grounding electrode conductor
[quote=Fred Warner;104696]Since all of the conductors in the SER must be considered conductors contained in the same cable and of the same circuit as per 300.4,[/quite]
300.4 addresses "300.4 Protection Against Physical Damage."
Not sure what you are referring to about 300.4 in relation to what you said?
then the EGC is not being used as a Grounded Conductor, therefore it isn't governed by parallel conductor rules,(not a parallel neutral) but rather by EGC rules found at 250.130.This section states (250.130(A)) that this connection shall be made by bonding the EGC to the Grounded Service Conductor AND the Grounding Electrode Conductor.
- - Equipment grounding conductor connections at the source of separately derived systems shall be made in accordance with 250.30(A)(1). Equipment grounding conductor connections at service equipment shall be made as indicated in 250.130(A) or (B). For replacement of non–grounding-type receptacles with grounding-type receptacles and for branch-circuit extensions only in existing installations that do not have an equipment grounding conductor in the branch circuit, connections shall be permitted as indicated in 250.130(C).
- - - (A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor.
- - - (B) For Ungrounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounding electrode conductor.
- - - (C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following:
- - - - (1) Any accessible point on the grounding electrode system as described in 250.50
- - - - (2) Any accessible point on the grounding electrode conductor
- - - - (3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
- - - - (4) For grounded systems, the grounded service conductor within the service equipment enclosure
- - - - (5) For ungrounded systems, the grounding terminal bar within the service equipment enclosure
- - - - - FPN: See 406.3(D) for the use of a ground-fault circuit-interrupting type of receptacle.
That what is shown in that photo:
- - - (A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor.
It would seem unusual to have this identical condition in both the metering enclosure and the service disconnecting means if they are in separate enclosures. (Not saying it hasn't been done countless times over the years) but certainly redundant. So, I guess each condition where this appears would best be evaluated on its own individual merits.
So, does that mean you are agreeing that it is not prohibited?
As I said, and you agreed, it would be redundant, but ... it is also therefore allowed, not against code, right?
http://www.cable.alcan.com/NR/rdonly...66C/0/serw.pdf
http://www.cable.alcan.com/alcancabl...SE+Style+R.htm
(bold and underlining are mine)
"Alcan Type SE Style R three conductor insulated, round-type Service Entrance Cable is designed for above-ground service entrance use, as well as interior wiring."
http://www.acewireco.com/pdfs/2670.pdf
"APPLICATION: Primarily used for interior “service - runs” from the main service to distribution panels and individual load centers; maximum conductor temperature of 75°C; maximum potential of 600 volts. Also used as branch circuit or feeders for wiring of ranges, wall - mounted ovens, counter - mounted cooking units, and clothes drying circuits where the a - c supply is not over 150 volts to ground. May be used in overhead service for attachment to the side of a building from the weatherhead to the meter equipment."
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10-12-2009, 01:01 PM #15
Re: Grounding electrode conductor
Jerry: I intended to cite 300.3(1) which in turn cites 310.4. Sorry. My bad.
As far as the redundancy, I don't think this 4th conductor acting as an equipment grounding conductor and bolted to the grounded conductor on each end termination could be called a parallel neutral, because it doesn't qualify under the definition of parallel conductor.
Do I believe it's code compliant.....not yet (keep working on me )........but something is telling me "no".
IMHO, and only MHO, It's a slippery slope when neutral return current may divide along 2 paths. In this particular scenario there would be a minimal amount of resistance which would in turn allow the opening of the OCPD.
It's just that there are two conductors originating in the metering enclosure and terminating in the service equipment in an identical method. This type of redundancy raises a red flag with me.
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10-12-2009, 01:16 PM #16
Re: Grounding electrode conductor
Fred,
You mean 300.3(B)(1), right?
By the way, 300.3(B)(1) references 310.4, not 300.4.
Those dang numbers git all confusing all da time.
As far as the redundancy, I don't think this 4th conductor acting as an equipment grounding conductor and bolted to the grounded conductor on each end termination could be called a parallel neutral, because it doesn't qualify under the definition of parallel conductor.
Do I believe it's code compliant.....not yet (keep working on me )........but something is telling me "no".
IMHO, and only MHO, It's a slippery slope when neutral return current may divide along 2 paths. In this particular scenario there would be a minimal amount of resistance which would in turn allow the opening of the OCPD.
It's just that there are two conductors originating in the metering enclosure and terminating in the service equipment in an identical method. This type of redundancy raises a red flag with me.
It really raises some dire warnings, however ... the SER cable has the groundING conductor sized the same as the groundED conductor (at least the ones I've seen do), so ... if the neural groundED conductor was lost, the groundING conductor would serve the same purpose, and, being as they are connected to the same thing a both ends, there should not be a problem, especially as the neutral groundED service entrance conductor is not even required to be insulated.
In that sense, they "act like" and "serve the purpose of" "parallel conductors" as addressed in 310.4 (depending on their size).
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10-12-2009, 02:06 PM #17
Re: Grounding electrode conductor
Are you sure that is not the Bond wire to the gas meter ?
They run those like that all the time here. Most of the time on the exterior wall or under the crawl space.
I'm ready for my beating...........
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10-12-2009, 03:07 PM #18
Re: Grounding electrode conductor
I think that the metering enclosure located outside also has a service disconnecting means in it and the 4-wire cable is just improperly terminated. This would make the most sense to me.
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10-12-2009, 05:40 PM #19
Re: Grounding electrode conductor
If that's the case, it's an easy fix. Simply have to install an equipment grounding bar and relocate the EGC's including the 4th conductor of the SER cable to it; then remove the bonding bolt from the neutral bar which will effectively "float" the neutral bus away from the enclosure and stop all that return current from traveling on the EQC's. But, it's still going to have to have the grounding electrode conductor removed from the neutral bar and brought out to the service equipment (located in the meter/disconnect enclosure) and terminated there.
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10-12-2009, 06:33 PM #20
Re: Grounding electrode conductor
We (at least some of us) have noticed but think otherwise.
There is a main in that panel, and ALL the equipment grounding wires are on that same terminal bar, which suggests to me that the only thing different is that they ran SER instead of SE, and that there is no disconnect outside (otherwise, why have one inside?).
If the scenario Fred and Ben are proposing is correct, then the correction is a lot more than simply relocating the 4th (equipment ground) wire to another terminal bar ... ALL the equipment grounding conductor would need to be relocated as well .. AND the neutral terminal bar would need to be verified that it is indeed not connected to the enclosure.
Mat is the only one who can clear those questions up for us.
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10-12-2009, 06:53 PM #21
Re: Grounding electrode conductor
Jerry, I am now convinced beyond a reasonable doubt that parallel paths on the line side of the service disconnect are permitted by NEC rules. The grounded conductor is used for all bonding and grounding purposes on the line side of the service disconnect. Thanks for your help.
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10-12-2009, 06:58 PM #22
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10-12-2009, 07:39 PM #23
Re: Grounding electrode conductor
That you did, apologies for missing it.
The neutral bar shown in the photo at the beginning of this thread has a removable bonding bolt.
But I did see a stranded neutral with what looks to be cut off and missing strands.
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