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Joined: Dec 2004
Posts: 1,064
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You can use any and all on the list if you want.

My point is the use of the word MUST.

Unless you are there while the foundation is dug, or while the water pipe is being installed, or if you decide to dig down 3' and at least 10' long to prove the water pipe actually meets the critia, you can't use it...

So why use it, unless you can prove it.

Also, the water pipe is the only electrode that MUST be supplemented by at least one of the others on the list. The only one that the code calls out to be supplemented.

I went to Mike's bonding/grounding course a while back and asked the same question to him, after a decussion we had on the same topic a while back, and I got hammered by some of you guys about this.

After searching and thinking about this, he concluded the same thing I am stating here.

It is a technical thing with regards to using the word MUST.
It doesn't really say that you MUST use it as a GE. It only states it MUST be supplemented, and it shall be bonded to the GES.

2 ground rods constitute a GES, then bond the water pipe to it, that way you don't have to prove or dig.


Dnk....




[This message has been edited by Dnkldorf (edited 01-16-2006).]

Joined: Jan 2003
Posts: 4,391
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OK if you feel better not calling it a grounding electrode so be it.

Has this change of name changed anything at all?

It's either a GE and connected with a conductor per 250.66 or it metal stuff that has to be bonded with a conductor sized per 250.66.

Again going with your view none of the items on the list have to be used as GEs only bonded to the GES.

I can see why you feel so strongly about this. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Joined: May 2003
Posts: 2,876
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e57 Offline
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This is why I often refer to water as a bond/electrode, once you bond it, it is by proxy an electrode in the grand sceme of things. (In the world of copper piping at least) Part of the system.

And "shall" does in effect mean "must'...


"Shall: indicating that something must happen or somebody is obliged to do something because of a rule or law."

Or: "Mandatory"
Quote
90.5 Mandatory Rules, Permissive Rules, and Explanatory Material.
(A) Mandatory Rules. Mandatory rules of this Code are those that identify actions that are specifically required or prohibited and are characterized by the use of the terms shall or shall not.

If a metal water pipe is there, it has to become part of the system. Many places considered it as the primary electrode... I think just because it was on top of the list... [Linked Image]

Now if it were a metal pipe inside, and a PVC underground outside, that would be different. At which point it is no longer an electrode. But it still would have to be bonded due to 250.104.

BTW Bob.... What is it about grounding these days that has you in such a tizzy? Is there a problem with the grounding system at home? Feel free to lay back on the couch and relax... It's better if you talk about it... [Linked Image]


Mark Heller
"Well - I oughta....." -Jackie Gleason
Joined: Jan 2003
Posts: 4,391
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Quote
BTW Bob.... What is it about grounding these days that has you in such a tizzy? Is there a problem with the grounding system at home?

I will make a deal, you explain to me what a 'primary electrode' is

Quote
Many places considered it as the primary electrode...

and I will tell you what is getting me in a 'tizzy'. [Linked Image]


Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Joined: Jan 2006
Posts: 44
M
Member
Did we forget equalizing the potential in the building systems? Why do we bond water lines and structural steel in commercial settings, place bare copper in concrete and yet we still use multipal grounding rods as well. Even if multipal ground rods get the job done should we not bond the water line (if it is not plastic) to insure equalizing the potential? I think I would leave the gas line alone,yeikes.

Joined: Aug 2004
Posts: 55
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wendel Offline OP
Member
Is this an accurate statement relative to primary and secondary grounding electrodes?

A grounding electrode system usually consists of a primary
grounding electrode, plus possibly a secondary electrode. A
primary electrode can be (if in direct contact with the earth):
10' of ground rod. 10' of well casing or metallic water pipe
(must be connected within 5' of pipe entrance to house). 20'
of copper wire buried in the bottom of the footings. A
secondary electrode will be required if the primary is a water
pipe or (NEC) if the primary electrode is >25 ohms to the
dirt.
It seems a secondary electrode is needed where a water pipe is used due to the fact water pipes deterioriate and can therefore be replaces with a nonconducting material like plastic at some time in the future.

[This message has been edited by wendel (edited 01-17-2006).]

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Posts: 650
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'Primary' versus 'secondary' grounding electrodes is a meaningless distinction _electrically_. There may be a legal/code/historical ramification, but in the present code there is no electrical distinction.

You can have effective versus ineffective grounding electrodes, and you can have bonded metal piping that is not a grounding electrode.

If it looks, smells, tastes, or conducts like a grounding electrode, the it must be tied to the grounding electrode system. All grounding electrodes tied to the grounding electrode system will function to a greater or lessor extent as part of the grounding electrode system.

250.50 tells you that _if available_, you must use all of the items listed in 250.52(A)(1) to (A)(6) as the grounding electrode system. If the electrodes are _not avaialble_, then you _must_ install one of items (A)(5) - (A)(7). So you _must_ have a grounding electrode that meets certain minimum requirements (size, material, depth, etc)

250.53(D)(2) tells us that item 250.52(A)(1) is not in and of itself sufficient, and that you must have additional grounding electrodes.

250.56 tells us that items 250.52(A)(5) and (A)(6) must meet certain performance criteria, _or_ that you must have yet another grounding electrode.

-Jon

Joined: Dec 2004
Posts: 1,064
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Member
Once again, a great explanation from Jon..


Dnk..

Joined: May 2005
Posts: 42
A
Member
Grounds rods are cheap.

Unless you live in an area where the ground is so hard you can't drive one, I don't know why you wouldn't just drive a ground rod or two to make sure you have a good ground.

The Code is the bare minimum.

[This message has been edited by Amazingmg (edited 01-17-2006).]

Joined: May 2002
Posts: 1,716
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Member
Jon, the 2005 has changed the wording from if available to All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.

This new wording does not give any exception to say a concrete encased electrode that was poured and buried before it could be bonded, it is in fact present and shall (or must to those who prefer must [Linked Image]) be bonded to the others that are present even if it means dragging out the dreaded chipping hammer.

Amazingmg, you do realize that rods are pretty much a waste of time don't you? Even if you drive 10 rods that might combine to get to 25 ohms they will only assist in dispersing lightning or a HV surge but really do nothing as far as people safety at our low voltages.

Roger

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