Grounding

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The electrical service is grounded to pipe because it is a built in ground when all plumbing is metal, Pipes don't need to be grounded per se.
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hwm54112
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WRONG. Completely wrong in every respect. The plumbing system is grounded to the electrical system's grounding electrode to eliminate the possibility of an electrical fault causing the plumbing to become energized. Pipes DO need to be grounded in order to prevent this. Bonding the plumbing to the electrical ground has *nothing* to do with grounding the electrical system, and *everything* to do with ensuring that the *plumbing* is grounded.
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Doug Miller (alphageek at milmac dot com)
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It's not that simple. "Bonding" the pipes to earth ground when they are not already connected to earth ground in fact opens the possibility that the pipes can now complete a circuit and kill some guy in the bathtub when the radio falls into the water.
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You'd probably get killed whether the plumbing was grounded or not.
Which would be pretty much your fault. What on earth were you doing with AC power anywhere near the tub?
In contrast, if you have a wiring fault going to ungrounded copper, you could get killed any time you touch _any_ part of the plumbing system.
I imagine you touch your kitchen faucet a lot more often than you drop an AC powered radio in your bathtub.
Or, at least one hopes so.
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Chris Lewis, Una confibula non set est
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Let me get this straight: are you claiming that bonding the pipes to earth ground creates the possibility of an electrocution hazard that would *not* exist if the pipes were *not* bonded?
Please explain.
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Doug Miller (alphageek at milmac dot com)
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Yes. In order to get electrocuted, you have to complete a path between a voltage source and a voltage sink. If the piping is grounded, it's a sink. If it's not, it isn't. If you're touching a voltage source, touching grounded piping (faucets, metal tubs and sinks) can kill you where it wouldn't were they not grounded.
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That is certainly a valid concept but to make it applicable we would be floating the whole house. The NEC (NFPA) made a decision 100 years ago to establish a ground level in each building and bond to that. 250.104 is pretty unambiguous
250.104 Bonding of Piping Systems and Exposed Structural Steel. (A) Metal Water Piping. The metal water piping system shall be bonded as required in (1), (2), (3), or (4) of this section. The bonding jumper(s) shall be installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible. (1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 except as permitted in 250.104(A)(2) and (A)(3).
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There is no requirement. Grounding to water piping is no longer acceptable for electrical service because of the possibility of PVC.
(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

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DanG wrote:

A common misconception. All interior metal water piping is required to be bonded to the electric service for safety. Think about it. Should those interior metal pipes be accidentally energized, you'd sure want the fault to be cleared before getting into the shower wouldn't ya? Incoming metal water service, if available, must still be used as the primary grounding electrode and supplemented by a ground rod to ensure that a ground be present should the incoming metal piping ever be replaced with plastic. If the OP doesn't have a grounding electrode of any kind, he should at least drive an 8 foot ground rod as close to the service as posssible and connect it to the electric service with a bare #4 wire. Better would to provide a second ground rod at least 6 feet away from the first rod, preferably 10 feet away.
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I'm building a new home. What I have done is driven a pair of 8 foot, 1/2" solid copper ground rods out in the overdig for the basement, separated by about 7 foot. They are bonded together with 6 AWG bare copper, and also bonded to the rebar in the footing where the wire comes in underneath the wall. All materials used were marked for "Direct Burial".
It's no problem to attach my pipes to ground, just wondering if it was necessary. I thought it might be. Thanks all for the replies.
Joe Michel
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: DanG wrote: : : >There is no requirement. Grounding to water piping is no : >longer : >acceptable for electrical service because of the possibility of : >PVC. : : A common misconception. : All interior metal water piping is required to be bonded to the : electric service for safety. Think about it. Should those interior : metal pipes be accidentally energized, you'd sure want the fault to be : cleared before getting into the shower wouldn't ya? Incoming metal : water service, if available, must still be used as the primary : grounding electrode and supplemented by a ground rod to ensure that a : ground be present should the incoming metal piping ever be replaced : with plastic. : If the OP doesn't have a grounding electrode of any kind, he should at : least drive an 8 foot ground rod as close to the service as posssible : and connect it to the electric service with a bare #4 wire. Better : would to provide a second ground rod at least 6 feet away from the : first rod, preferably 10 feet away.
Boy, you started out pretty well, but you sure botched the second part of your response! IMO, that makes everything you said suspect and points to a serious lack of knowledge on your part, meaing in turn that you "guessed" the answers you gave rathern than "knew" them.
Please don't do that!
:
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POP wrote:
: DanG wrote:
: : >There is no requirement. Grounding to water piping is no : >longer : >acceptable for electrical service because of the possibility of : >PVC. : : A common misconception. : All interior metal water piping is required to be bonded to the : electric service for safety. Think about it. Should those interior : metal pipes be accidentally energized, you'd sure want the fault to be : cleared before getting into the shower wouldn't ya? Incoming metal : water service, if available, must still be used as the primary : grounding electrode and supplemented by a ground rod to ensure that a : ground be present should the incoming metal piping ever be replaced : with plastic. : If the OP doesn't have a grounding electrode of any kind, he should at : least drive an 8 foot ground rod as close to the service as posssible : and connect it to the electric service with a bare #4 wire. Better : would to provide a second ground rod at least 6 feet away from the : first rod, preferably 10 feet away.

By all means offer your rebutal, other than "you sure botched the second part of your response!" I've been an electrician for 28 years and hold a master electrician's license in two states. I can back ALL of my statements with NEC to the letter. State your qualifications. Clueless armchair electrician's like you are why there are very few real electrician's who bother with this group anymore. We spend more time responding to morons like you, correcting dangerous advise, while the correct responses get buried in all the drivil. Good old AHR, hasn't changed a bit.
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: :: DanG wrote: : : :: :: >There is no requirement. Grounding to water piping is no :: >longer :: >acceptable for electrical service because of the possibility : of :: >PVC. :: :: A common misconception. :: All interior metal water piping is required to be bonded to the :: electric service for safety. Think about it. Should those : interior :: metal pipes be accidentally energized, you'd sure want the : fault to be :: cleared before getting into the shower wouldn't ya? Incoming : metal :: water service, if available, must still be used as the primary :: grounding electrode and supplemented by a ground rod to ensure : that a :: ground be present should the incoming metal piping ever be : replaced :: with plastic. :: If the OP doesn't have a grounding electrode of any kind, he : should at :: least drive an 8 foot ground rod as close to the service as : posssible :: and connect it to the electric service with a bare #4 wire. : Better :: would to provide a second ground rod at least 6 feet away from : the :: first rod, preferably 10 feet away. : : >Boy, you started out pretty well, but you sure botched the second : >part of your response! IMO, that makes everything you said : >suspect and points to a serious lack of knowledge on your part, : >meaing in turn that you "guessed" the answers you gave rathern : >than "knew" them. : : : >Please don't do that! : : By all means offer your rebutal, other than "you sure botched the : second : part of your response!" I've been an electrician for 28 years and : hold a master electrician's license in two states. I can back ALL of : my statements with NEC to the letter. State your qualifications. : Clueless armchair electrician's like you are why there are very few : real electrician's who bother with this group anymore. We spend more : time responding to morons like you, correcting dangerous advise, while : the correct responses get buried in all the drivil. Good old AHR, : hasn't changed a bit. : Sorry, not for a low-life as you are acting. Read the follows-ons; other people got it right. And you know it. won't be responding further to you not worth the ether.
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wrote:

The only thing I saw with 500's post was that you only need a #6 GEC for a ground rod but if you use anything smaller than 4 it has to be in conduit so the advice was still sound.
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WRONG.
That wasn't the question.
The question was, is it required to bond the metal water piping to the electrical system ground? And the answer is YES. This is explicitly required by the National Electrical Code.
You have it backwards: the objective here is to ensure that the *plumbing* is grounded.

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Doug Miller (alphageek at milmac dot com)
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In the parts of the United States that have adopted the National Electric Code Underground water piping that is ten or more feet in length must be used as an electrode of the grounding electrode system. That is true whether there is any metallic piping inside the home or not. So your statement that there is no requirement is misleading. Even metal well casings that are close enough to the building to be "available on the premise" must be used as a grounding electrode. So in areas were the US National Electric Code is enforced there is definitely a requirement to use underground metallic water piping as a grounding electrode. -- Tom Horne
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Yes you must bond all metallic piping inside a residence "that may become energized". Do your bonding inside the electrical service panel on the ground bus.
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Carefully notice what SQLit has written. Incoming metal water pipe must be bonded to breaker box safety ground. That is a different ground from earth ground. To keep pipes, including utility side of water pipe, at a common voltage potential, then water pipe must be bonded to breaker box ground - the electrical service panel ground bus.
SQLit wrote:

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snipped-for-privacy@navix.net wrote:

Yes. All interior metal water piping is required by Code to be bonded to the electrical system ground. This has nothing whatever to do with grounding the electrical system; rather, the purpose of this requirement is to ensure that the plumbing system is grounded and cannot become live due to an electrical fault somewhere.
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Doug Miller (alphageek at milmac dot com)
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snipped-for-privacy@navix.net wrote:

Indirectly, yes. The copper pipes have to be connected to the electrical service ground. The electrical service ground has to be connected to the grounding electrodes (rods).
You can connect the pipes to the main electrical panel, or to the big wire (GEC) that goes to a ground electrode, whichever is easier.
Use a big copper wire. Bare #6 solid wire is pretty common.
Best regards, Bob
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