Continueous GEC

Status
Not open for further replies.
S

sfav8r

Senior Member
Location
San Francisco Bay Area
I just had an inspection in a city I normally don't work in (service upgrade).

Everything was OK, however the inspector didn't like the way I did the EGC. I ran an EGC from the new panel to the 1" copper water main where it enters the foundation, and I ran another EGC from the new panel to an 8' ground rod near the new panel.

The problem she had with it, is that it was two pieces of wire (one for each system). She wanted one continueous wire from the rod to the pipe to the panel.

It's not really a big deal, but it seems to me that the way I did it is more fail safe. If I do it her way, there is really the single ground point (the pipes) which are grounded additionally by the rod. In my way they are two completely different systems. Even if the EGC to the pipes gets broken, the completely differnet rod system still grounds the system.

I thought the the requirement for continuous EGC referred to splices between the ground rod (or pipes) and the panel, not between the two systems.

Is she right? FYI she passed the job, this is just for future reference)

Thanks
 
Re: Continueous GEC

IMO no she is not but it is a common mistake.

You can run from the panel to the as many grounding electrode conductors as you want.

You could also run from the panel to the water pipe, then run a separate wire from the water pipe to a ground rod.

This is one my 'favorite' NEC handbook graphics, look at it carefully and you can see what is considered the GEC and what is considered bonding jumpers.

Bonding_Jumpers.JPG


You might suggest she take a look at the handbook.
 
Re: Continueous GEC

I guess it would help to look at the code section.


2002 NEC
250.64(C) Continuous. The grounding electrode conductor shall be installed in one continuous length without a splice or joint, unless spliced only by irreversible compression-type connectors listed for the purpose or by the exothermic welding process.
Click to expand...
No where in that section does it say you may only run one GEC, but each GEC you run would have to be continuous.

Then there is 250.64(F)

2002 NEC
(F) To Electrode(s). A grounding electrode conductor shall be permitted to be run to any convenient grounding electrode available in the grounding electrode system or to one or more grounding electrode(s) individually. The grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all the electrodes connected to it.
Click to expand...
 
Re: Continueous GEC

It's not really a big deal
Click to expand...
I think it's a big deal. There can be significant time and materials cost in the electrode system and conductors.

And it's really as straight forward as Iwire's illustration. I've ran into too many inspectors and EC's that have serious flaws in their understanding of the grounding system.

I've been told to replace jumpers with a continuous GEC and I'm just not into having to act as an educator for people that should know this stuff.
 
Re: Continueous GEC

and I ran another EGC from the new panel to an 8' ground rod near the new panel.
Click to expand...
Anyone thinking what I'm thinking? ;) As for the original question I have to agree with the other guys. Bob's picture is a good example. Fo me alot of times seeing something in a graphic is alot clearer than reading words.
 
Re: Continueous GEC

Anyone thinking what I'm thinking?
Click to expand...
Yeah, I didn't notice that before.

Are there two panels connected to the grounding electrode system?

Are there two grounding electrode systems?

I'm not clear on the installation now.

Edit: I don't think I know what I'm talking about. It looks fine again now.

I guess I don't know what you,re thinking Scott.

[ February 12, 2005, 05:46 PM: Message edited by: physis ]
 
Re: Continueous GEC

I can see that some inspectors read it that way. I had to get clear that I was not clear about it. not all "electrodes" have to be connected unspliced. The explanation in the 2002 handbook illustration @250.15 indicates that it doesn't have to rise continuous to any panel.

Other than being unclear on the intent of the NEC about this, I agree that I have interpreted that only one needs to rise unspliced to the panel, and supplemental electrodes can even be connected to that GEC, and have never been called on it when I was working.

Does that make 3 Bob, or is it too waffled an answer?

paul :)

[ February 12, 2005, 11:18 PM: Message edited by: apauling ]
 
Re: Continueous GEC

Originally posted by physis:
...and I'm just not into having to act as an educator for people that should know this stuff.
Click to expand...
Easy there. If the person is willing to listen and will accept a different interpretation, it's not so bad. The ones that won't listen won't take an education anyway. :)

[ February 13, 2005, 07:00 AM: Message edited by: georgestolz ]
 
Re: Continueous GEC

I guess I don't know what you,re thinking Scott.
Click to expand...
Actually what I was getting at was the requirement for 25 ohms or less for the ground rod. Since the post indicates one ground rod I am assuming a test was done and it was less than 25 ohms. More likely, the inspector is not aware of this requirement based on the lack of knowledge on the gec.

[ February 13, 2005, 08:55 AM: Message edited by: electricmanscott ]
 
Re: Continueous GEC

Easy there. If the person is willing to listen and will accept a different interpretation, it's not so bad. The ones that won't listen won't take an education anyway. We are talking about one of the driest, crosseyed articles in the NEC here.
Click to expand...
I mostly agree with you there George. (you know I'm gonna say "but" now). :D

But. Most of an inspector's attention is on the grounding system when inspecting a new service. They simply have to know it. And this is a more or less daily function of a building departmenmt.

Also, a lot of the inspectors who misunderstand it are kind of from the old school and don't change their minds about things so easily.

It can be a real hassle to straighten out something that never really needed to be straightened out.

I thought it sounded a little harsh of me too. Because I actually enjoy helping people with understanding things. (not that I'm particularly well informed) But this isn't an area for on the job training by someone who has work to do.

Edit: Scott, I thought about that but didn't think that's what you were thinking. :D

[ February 13, 2005, 01:36 PM: Message edited by: physis ]
 
Re: Continueous GEC

Let me point out that the original question addressed the Grounding Electrode Conductor (GEC), but then incorrectly used the abbreviation ?EGC,? for Equipment Grounding Conductor. I infer that the intent was to discuss the GEC.
 
Re: Continueous GEC

My reading of the 25 ohms to ground issue is that it only applies to rods, pipes, and plates that are the sole electrode. With the waterpipe as the electrode, the rod is a supplemental electrode and doesn't have to conform to the 25 ohm requirement. 250.56 2005

What makes me say this is the wording "a single electrode"

also, the 2005 Code has changes all throughout 250.64 concerning GEC installation. The only real change I see is that it is permissible to use a copper or aluminum buss bar as a central connection point for all of the electrodes. For example, all of the separate electrodes could have a GEC running to a common grounding bus located somewhere in the building, then a single GEC could be run to the main disconnect. The GEC would not have to run "continuous" to any electrode in this case. This has been commonly done in telecommunications buildings for as long as I have been an electrician.

[ February 14, 2005, 03:23 PM: Message edited by: crossman ]
 
Re: Continueous GEC

Crossman
You must have missed this:
250.53(D)(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(7). Where the supplemental electrode is a rod, pipe, or plate type, it shall comply with 250.56. The supplemental electrode shall be permitted to be bonded to the grounding electrode conductor, the grounded service-entrance conductor, the nonflexible grounded service raceway, or any grounded service enclosure.
Click to expand...
Look at the bold requirment!
 
Re: Continueous GEC

I too missed it about 3 years ago I posted a statment like you and I was told that there is a differance between supplemental and Supplementary I was trying to figure out what they were talking about since this was getting confussing and when I re-read it I saw the requirment. :roll:

Of course this section here it what was throwing me off:
250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56 , but the earth shall not be used as the sole equipment grounding conductor.
Click to expand...
See Bold
 
Re: Continueous GEC

Look at 250.64(F)

"any convenient grounding electrode available"

Edit: Sorry, that's not the one you're interested in.

Edit: Sorry again, it is the one you're interested in. But also 250.64(C)

The GEC only has to be continuous to the first electrode in the system. After that you can use jumpers.

[ February 15, 2005, 10:07 PM: Message edited by: physis ]
 
Re: Continueous GEC

The GEC is required to be continuous and unbroken. It can be spliced if it is irreversible, such as crimping or exothermic welding.

lets say one uses the conductor to the cold water as the GEC.

250.50 Grounding Electrode System. requires the other electrode if available to be BONDED together to provide the GEC System.

So we supplement the cold water with a conductor from the steel or ground rod or concrete encased, that is connected (bonded) to the GEC. These conductors are not required to be unspliced and continuous.
 
Re: Continueous GEC

No.

250.64(C) Only says the GEC has to be continuous. Not continuous to each electrode.

This is kind of stupid but:

250.64(F) Say that one end of the GEC only has to go to any convenient electrode.

And.

Article 100 "Grouding Electrode Conductor" Says where the other end goes. (To the service)

The conductors between the electrodes are allowed to be bonding jumpers.

Editted to be more helpful. :)

[ February 16, 2005, 03:31 AM: Message edited by: physis ]
 
Status
Not open for further replies.
Top