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Thread: Main ground only to Water line??
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06-11-2012, 04:10 PM #1
Main ground only to Water line??
Inspected a home built in 1950, which has some updated electrical in the 100 amp main box, but the only ground wire, a #6awg 500 volt stranded wire (black wire in photo) was clamped to the water line just a few feet from the box. While there was a ground across the water meter of the same wire, I am not convinced this is proper and am calling it out to be looked at by a licensed electrician. IMNO (In My Nonelectrical Opinon) it should have an additional exterior ground rod along with this ground wire running all the way to the other side of the meter, as well as a bond across the meter and hwt/gas line. How much of this is just "recommendation" versus "required". I wanted to see if anyone would take a look and give me some advice I can include.
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06-11-2012, 04:33 PM #2
Re: Main ground only to Water line??
Under the modern NEC the water pipe electrode is required to be supplemented by one additional electrode. However depending on the age of the service this requirement might not have been around at the time of installation. Do you know when the service was installed?
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06-12-2012, 03:37 AM #3
Re: Main ground only to Water line??
No Robert, the homeowner was placed in a nursing home. However, based on the yellow interior Romex that only recently came out (a year or two ago to my knowledge), work must have been done recently. Would installing that new line have required updating the ground?
Also, should the connection to the water pipe go to the supply side of the water meter, or is it okay to be clamped to the water line 20 feet away?
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06-12-2012, 03:49 AM #4
Re: Main ground only to Water line??
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06-12-2012, 05:48 AM #5
Re: Main ground only to Water line??
If the meter was removed and a event happened there would be no grounding for the purpose of a lightning strike or high voltage surge.
Here is what the NEC says about system grounding.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that
are grounded shall be connected to earth in a manner that
will limit the voltage imposed by lightning, line surges, or
unintentional contact with higher-voltage lines and that will
stabilize the voltage to earth during normal operation.
Receptacle grounding would continue to work the same as it is not dependent on a ground rod or water line or any other electrode.
All answers based on unamended National Electrical codes.
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06-12-2012, 05:51 AM #6
Re: Main ground only to Water line??
Adding a new circuit should not have triggered a requirement to upgrade the system grounding.
The GEC connection used to be allowed to just connect to an accessible point on the water line. Now it is specified as within 5' of where it enters the house.
All answers based on unamended National Electrical codes.
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06-12-2012, 09:00 AM #7
Re: Main ground only to Water line??
I'll echo what others are pointing out...it may have been allowed at one time but is now obviously an outdated way of doing things. Adding some branches and doing other minor work would not necessarily have required bringing the grounding method up to code. A replacement of the service or panel would have.
We're really only talking about less than $100 worth of materials and a couple of hours of work. I am sure the agile son or grandson of the HO could do the work quite easily.
Nice that the meter was bonded across, though.
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06-12-2012, 09:23 AM #8
Re: Main ground only to Water line??
Grounding is a bit unique in that quantity trumps quality. When metallic water lines started they were metallic "all the way". Now the likelyhood is that a copper water system will end shortly after exiting the structure and it's grounding effectiveness limited. Today a metal underground water pipe must be at least 10' in the ground and must be supplemented by another grounding electrode, ( ground rod ), of at least 8'. The favored grounding electrode today is the foundation re-bar, but the sequence of construction usually makes that difficult to happen. The fact that water by itself can be conductive makes it important that conductive waste & other systems be bonded to the main service ground.
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06-12-2012, 03:38 PM #9
Re: Main ground only to Water line??
Incorrect - it is the quality of the ground which matters.
Case in point: If one ground rod does not provide a good ground, you install a second ground rod at least 6 feet away (because the effective area of influence of each ground rod is 3 feet and you do not want those areas to overlap).
Okay, seems that quantity is better than quality, right?
WRONG!
Do you install a third ground rod if the first two do not provide a good ground? NOPE! Quantity is not better than quality.
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06-12-2012, 04:02 PM #10
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06-12-2012, 07:28 PM #11
Re: Main ground only to Water line??
By the way, Chris, you probably saw the branch circuit grounding wires doubled with neutrals, wrong.
All those old cables pulled through one big knockout without a bushing is not good.
So there's plenty of reason for a visit by an electrician.
John Kogel, RHI, BC HI Lic #47455
www.allsafehome.ca
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06-13-2012, 05:22 AM #12
Re: Main ground only to Water line??
On the left side of the panel those look like individual conductors, not cables. It looks like the neutrals may be in the EMT conduit. Both of these would be wrong.
All answers based on unamended National Electrical codes.
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06-13-2012, 10:33 AM #13
Re: Main ground only to Water line??
OK Mr. semantics professor. I left out the word "perceived". Quantity is better than "perceived" quality. The reality is that the resistence is rarely, if ever, actually tested with a meter. Even the 1 ohm single ground rod Robert mentioned can be a random situation. The presense of moisture, the elements in the soil, when it last rained, different depths / strata, etc are all random determinates. The best ground covers the most possibilities. Foundation re-bar is killer at this because of the "quantity" of exposure. Sink multiple ground rods into dry sand and nothing is accomplished. Ground rods are often driven under the rain shadow of soffits, limiting their effectiveness. Perhaps better to say quantity means quality. Unlike like you J.P., I am not omnipotent, have been "WRONG !", ( why so incredibly argumentative ? ), before and hopefully have many more to go. I do not need to pretend that I already knew what I've just been taught.
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06-13-2012, 12:31 PM #14
Re: Main ground only to Water line??
I tend to agree with your "semantical" point. The NEC will tell us to put in two rods if the resistivity is too low and then just leaves it at that. Two rods at 25 ohms isn't going to be a helluva lot better than one at 25...still individually over the 25 ohm limit and I don't recall a 12.5 ohm limit listed in the NEC...parallel paths be damned.
The NEC, therefore, assumes a poor quality ground and attempts an automatic correction by increasing the quantity and assuming an increase in quality. These are all assumptions. It's deemed good enough.
Our family lake cabin recently suffered a catastrophic destruction of the service and we had to install all new. The 50's era water pipe ground was, of course, insufficient for the new service. I actually had to call the state inspector to get him to clarify why I needed two ground rods if I could prove that I had a low resistance ground. He off-handedly remarked (putting it nicely) that if anybody wanted to buy one of them there fancy schmancy ground testers that cost several thousands of dollars and then prove...yada yada yada. I didn't try to argue because I knew that this guy could be trouble and he was the one who might be signing off the work. We just put in two rods...more expensive in the long run...but "easier".
I just happen to have one of those fancy schmancy doodads...it's one of the things I use in my job to put food on the table. But, you cannot argue with "experts"...even if you know more than them.
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06-13-2012, 02:25 PM #15
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06-13-2012, 03:00 PM #16
Re: Main ground only to Water line??
Garry,
It is not about semantics, and cuba_pete is on the right track, then he gets derailed.
The NEC stops at the second rod because tests have shown that adding more rods (increasing "quantity") does not affect the "quality" of the ground to any significant effect.
Thus the NEC recognizes that "quantity", beyond two, does little to no good.
It would be better to install the ONE driven rod in accordance with the code: (underlining and bold are mine)
- 250.53 Grounding Electrode System Installation.
- - - FPN: See 547.9 and 547.10 for special grounding and bonding requirements for agricultural buildings.
- - (A) Rod, Pipe, and Plate Electrodes. Where practicable, rod, pipe, and plate electrodes shall be embedded below permanent moisture level. Rod, pipe, and plate electrodes shall be free from nonconductive coatings such as paint or enamel.
Instead, driven rods are typically installed like this:
- 250.53
- - (G) Rod and Pipe Electrodes. The electrode shall be installed such that at least 2.44 m (8 ft) of length is in contact with the soil. It shall be driven to a depth of not less than 2.44 m (8 ft) except that, where rock bottom is encountered, the electrode shall be driven at an oblique angle not to exceed 45 degrees from the vertical or, where rock bottom is encountered at an angle up to 45 degrees, the electrode shall be permitted to be buried in a trench that is at least 750 mm (30 in.) deep. The upper end of the electrode shall be flush with or below ground level unless the aboveground end and the grounding electrode conductor attachment are protected against physical damage as specified in 250.10.
If the 8 foot rod was driven to meet 250.53(A) it is likely that the "quality" of the ground would be good, however, most are only driven to meet 250.53(G) - 8 feet - .
Thus the NEC recognizes "quality" over "quantity" as the NEC "quantity" stops at two (2) for driven rods with poor ground resistance ("quality") as the NEC recognizes that the "quality" of the ground will not change much with additional driven rods.
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06-13-2012, 03:01 PM #17
Re: Main ground only to Water line??
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06-13-2012, 09:34 PM #18
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06-14-2012, 03:12 AM #19
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06-14-2012, 09:58 AM #20
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06-15-2012, 07:57 PM #21
Re: Main ground only to Water line??
Just a clarifying point here.
Chapter 2, Article 250.52(A), Grounding Electrodes.
The metal underground waterpipe must be a min. of 10' or longer, buried in earth.
Also, one supplemental ground rod is required. At least from 2008 forward. I cannot find my 2002 or 2005 NEC books.
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06-16-2012, 04:15 AM #22
Re: Main ground only to Water line??
Yes, a water pipe must have 10' in contact with the earth to qualify as an electrode and it's required to be supplemented by at least one other electrode but that electrode is not required to be a rod. Also the 2011 NEC requires two rods or you can use the exception, that is, that you can prove that a single rod has a resistance of 25 ohms or less. Earlier editions of the NEC required only one rod but you needed to prove that the single rod had a resistance of 25 ohms or less or you could simply install two rods and ignore the 25 ohm requirement altogether. For all intents and purposes two rods will usually be required.
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06-18-2012, 05:23 PM #23
Re: Main ground only to Water line??
Unless you have the testing gear & the knowledge to use it, that is correct, it's cheaper to drive 2 rods & be done w/ it.
That panel is at least 20 years old or more as they use the Challenger breakers not the Bryant / Westinghouse BR breakers rebranded as Challenger that were used while they were owned by Westinghouse, which sold their electrical divisions to Eaton about 1995.
Do those NM cables entering in the center KO's at least have some sort of a connector? Still would not be compliant but at least no sharp edges to chaff them.
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06-18-2012, 06:19 PM #24
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06-19-2012, 03:18 AM #25
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06-19-2012, 05:51 AM #26
Re: Main ground only to Water line??
Not going to quote each individual so where do we start?
How about with the original question?
Based on the pictures, the service is at least 20 years old and the grounding to the nearest cold water line was all that was required back then.
The addition of a branch circuit, obviously subsequent to the panel's original installation, would not require updating the grounding.
By 2008 NEC, (NY has not adopted 2011), connection to the metal water piping shall not be made beyond five feet from its entry to the premises.
Nobody questioned the unjacketed, unfused cable entering the panel?
BTW, yellow jacketed NM cable has been around since 2002 or so.
What would happen if the water meter was removed?
Nothing, unless the neutral to the service was compromised and the earth was being utilized as the return path to the point of origination. (Transformer)
If the neutral was compromised, depending on the current draw imposed upon the metal water piping, anything from a tiny spark to a large, blue flame would be experienced by the individual disconnecting such.
Personally, I have always recommended "jumpering" across the meter prior to removal for just that purpose.
During a lightning strike of an improperly grounded electrical system, the results can be detrimental for any device that contains a circuit board.
Additionally, NEC 250.50 indicates that "All grounding electrodes described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system."
I mention that because here in upstate NY, we have to assume that the incoming water electrode is indeed 10 feet in contact with the earth and therefore is required to be bonded to the GEC.
If a contractor chooses to prove it is not 10 feet in contact with the earth, dig it up. ( Plastic water line replacement will change that concept soon.)
That results in some rather lengthy runs of expensive #6 or #4 copper wire. #8 is adequate for a 100A service, however; it requires protection.
Rich, anything #6 or larger does not require protection.
Yes, Jerry can be Mr. Semantics, however; he can also be correct most of the time. (Except when he argues with me.... )
QUALITY is the desired result for grounding and bonding.
You used to be directed to prove that a single means of ground was 25 ohms or less.
The option was to install a supplemental ground.
Most people chose the option. (Unless like Cuba Pete you owned the proper piece of test equipment. )
Glad we all agreed on what was deemed correct and therefore must be so.
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06-19-2012, 01:33 PM #27
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06-19-2012, 03:20 PM #28
Re: Main ground only to Water line??
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06-19-2012, 03:44 PM #29
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06-19-2012, 05:39 PM #30
Re: Main ground only to Water line??
So, putting on my Swami turban, Carnac says there is no guidelines, rules, standards, acceptable practice, etc., stating how or what constitutes acceptable mechanical protection that you would use protect the cable while it's running down the wall and going to the ground rod; conduit to ground; run along ground to rod; 3" underground to rod, just sprinkle with dirt; sleeved to rod?
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06-19-2012, 06:06 PM #31
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06-20-2012, 06:36 AM #32
Re: Main ground only to Water line??
250.64(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 4AWG or larger copper or aluminum grounding electrode conductor shall be protected where exposed to physical damage. A 6AWG 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, electrical metallic tubing, or cable armor. Grounding electrode conductors smaller than 6AWG shall be in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or cable armor.
Is a GEC, fastened securely to builing construction, traversing vertically to grade subject to physical damage?
Anyone use a string trimmer around the house?
Typically, according to the installer, no one at the property owns a string trimmer.
All is subject to interpretation.
Where the question of how deep such a conductor is required to be buried arises, I'm sure someone will point out code language that indicates that there is an actual depth proscribed. See table 300.5 and 300.5(D)(1)
Does anyone bury to that depth?
In most circumstances, no.
In urban areas we are just happy if the GEC is still present when we inspect.
Most often, it will be stolen to be sold as scrap.
At least once a month, I get a call from the POCO that upon arrival to connect a service, the meter can, riser, SE cable etc. is missing.
It was there when I inspected it.
Welcome to my world.
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06-20-2012, 08:38 AM #33
Re: Main ground only to Water line??
Would be hard to enforce that Article the way it is worded. A GEC is neither a cable or a conduit.
300.5 Underground Installations.
(A) Minimum Cover Requirements.Direct-buried cable
or conduit or other raceways shall be installed to meet the
minimum cover requirements of Table 300.5.
All answers based on unamended National Electrical codes.
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06-20-2012, 08:57 AM #34
Re: Main ground only to Water line??
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06-20-2012, 02:47 PM #35
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06-21-2012, 06:40 AM #36
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06-21-2012, 06:44 AM #37
Re: Main ground only to Water line??
Last edited by Richard D. Fornataro; 06-21-2012 at 06:49 AM. Reason: addition
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06-21-2012, 08:28 AM #38
Re: Main ground only to Water line??
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06-21-2012, 08:35 AM #39
Re: Main ground only to Water line??
I just use a pdf version of the NEC.
All answers based on unamended National Electrical codes.
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06-21-2012, 12:57 PM #40
Re: Main ground only to Water line??
I know that there are digital versions available. CD Rom and PDF but unfortunately, the municipality I work for has yet to enter the 21st century and approved purchase of such.
So, for now, I just enhance my typing skills as I reproduce code verbatim.
Unfortunately, I have a limited amount of time to participate in this forum and at times, as denoted in previous commentary on this subject, I have neglected to verify information that I cull from the tornado of thoughts racing around in my already confused brain.
Thanks for understanding.
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06-21-2012, 01:26 PM #41
Re: Main ground only to Water line??
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06-21-2012, 01:35 PM #42
Re: Main ground only to Water line??
The Dragon voice recognition software is very accurate.
All answers based on unamended National Electrical codes.
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06-21-2012, 01:36 PM #43
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06-24-2012, 01:36 PM #44
Re: Main ground only to Water line??
Yes, way back when... the only electrode required was the water pipe which did enter as metallic from the earth at least 10 to 20 feet to the utility. Some were only a few feet to a well house outside.
Distinctions have been made over the years obviously, but none so much as to the concrete encased electrode (where available) which negates the water pipe requirement (other than bonding).
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06-24-2012, 01:46 PM #45
Re: Main ground only to Water line??
... where "present" ... at one time the code said where "available" but many AHJ decided that if it was not "available" at the time the electrical contractor was there, oh well, so be it, not needed.
... because of those AHJ, the requirement is now, and has been for a while, where "present", and if it is "present" and they forgot to make it "available" ... oh well, get the chipping hammer out.
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06-24-2012, 03:06 PM #46
Re: Main ground only to Water line??
There he goes... semantics again.
I think all the readers knew what was meant.
In my way of thinking, if it is present, then it is available.
1/2, 20ft or greater, it will be used as an electrode regardless.
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06-24-2012, 03:49 PM #47
Re: Main ground only to Water line??
Semantic IS CRITICAL at times, and it was not me, it was the NEC and those AHJ which keyed in on the semantics.
"available" *does not mean* "present"
A steel rebar in a concrete footing is "present", but it is not "available". When the code stated "when available", that was not required to be used as it was already encased in concrete, but it is "present", and the newer wording states that *IF* *PRESENT* it shall be used.
A steel rebar in a concrete footing which is not yet poured is BOTH "present" AND "available".
Bob, if you don't like the semantics argument, go talk to NFPA and those who write the NEC and find out why the semantics was addressed.
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06-25-2012, 03:47 AM #48
Re: Main ground only to Water line??
Bob, you need to be SPECIFIC when describing something that is technical in nature, or interpreting a rule or regulation. If for no other reason, so you full understand what it it is saying or what it is not saying.
If you are not specific--reader A may think one thing (because that's is their experience level), and reader B may think something else (for the same reason).
Remember this, communication at its best--is a hazardous process!
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06-26-2012, 07:48 PM #49
Re: Main ground only to Water line??
Does anyone else here use NEC Plus code? It has the 2002 through 2011 cycles online, searchable with comments.
Here is an example this is the 08 code with references to the 05 (they are highlighted online) -
Changed From 2005
•250.64: Specified the locations in an electrical system where grounding electrode conductors are installed.
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).
(A) Aluminum or Copper-Clad Aluminum Conductors. Bare aluminum or copper-clad aluminum grounding conductors shall not be used where in direct contact with masonry or the earth or where subject to corrosive conditions. Where used outside, aluminum or copper-clad aluminum grounding conductors shall not be terminated within 450 mm (18 in.) of the earth. See related ROP Staff Note
(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. See related ROP ROC Staff Note
See 250.64(E) for additional information on situations in which raceways enclose the grounding electrode conductor. Also see the commentary following 250.64(E) and the illustration that accompanies that commentary, Exhibit 250.28, for installation requirements for metal raceways used to install and physically protect the grounding electrode conductor(s).
(C) Continuous. Grounding electrode conductor(s) shall be installed in one continuous length without a splice or joint except as permitted in (1) and (2): See related ROC UL
Changed From 2005
•250.64(C): Relocated provisions on busbar connections to to 250.64(F).
Don Hester
NCW Home Inspections, LLC
Wa. St. Licensed H I #647, WSDA #80050, http://www.ncwhomeinspections.com
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06-27-2012, 06:02 AM #50
Re: Main ground only to Water line??
Don,
Since NEC Plus is a subscription site, can I have your passcode?
The municipality I work for would never pay for something so useful.
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06-27-2012, 08:15 AM #51
Re: Main ground only to Water line??
Richard,
Sure if you give me half my subscription cost
I just find it a very easy way to get information and I like that if has notes and graphics.
I have the books also but sure is nice to go in by revision look something up and be able to compare it with prior or newer versions.
Don Hester
NCW Home Inspections, LLC
Wa. St. Licensed H I #647, WSDA #80050, http://www.ncwhomeinspections.com
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06-27-2012, 10:34 AM #52
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07-03-2012, 10:24 PM #53
Re: Main ground only to Water line??
Are there digitized versions of codes or do those who do the voluminous code citing using viice recognition software ?
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07-04-2012, 05:22 AM #54
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07-04-2012, 10:14 AM #55
Re: Main ground only to Water line??
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07-10-2012, 05:18 PM #56
Re: Main ground only to Water line??
Exactly my point, if the electrode is present (in the crete) then it is available as the G.E., regardless if accessible to the electrician or not.
Semantically speaking, there is no mention of 'readably accessible' to be connected to.... so get out the chipping hammer eh
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