NFPA 70 + NFPA 13 conflict

[dnem]

Deleted post simply because it is best if I just be still and not get invloved in this funny thread.

:roll: Oh come now there big fella ,.you're going to walk away after making that comment :roll:

I'm going to guess that his deleted comment was something like
"What goes around comes around"

speaking with some inspectors is not pleasant

Did I guess it right ?

 

[cschmid]

Dave thanks for your insight here points I have not considered before and will look at from now on..especially since sprinkler systems are moving toward being required in all buildings..

 

[LarryFine]

Speaking as an inspector and as a former contractor, speaking with some inspectors is not pleasant, even when an agreement is reached that both parties are OK with.

"Ah, Daniel-san! Myagi have hope for you!" :grin:

 

[jwelectric]

Oh come now there big fella ,.you're going to walk away after making that comment

I just simply said that after reading this thread it is obvious that some just don?t have any understanding of the bonding procedure so they just make up their own rules as they go along.

The bonding of a sprinkler system with or without 10 ft. in the ground will not make the sprinkler an electrode no more than bonding the flexible gas pipe with #6 makes the gas pipe an electrode. Remember that some gas appliances are fed from a remote tank that has copper buried underground from the tank to the building.

Then this junk of bonding the hot water pipes when all that 250.104 requires is the metal pipe be bonded and the point of bonding be assessable. No where does it mention the difference between hot and cold.

5-236 Log #2432 NEC-P05 Final Action: Reject
(250.104(A)(1))
____________________________________________________________
Submitter: Robert P. McGann, City of Cambridge
Recommendation: Revise text to read as follows:
Metal water piping system(s) that is likely to be energized, installed in or attached to a building or structure shall be bonded.
Substantiation: With much expanded use of plastic water piping system(s) isolating section of metal piping systems. This type of installation leaves contractors and inspectors what is required to be bonded.
Panel Meeting Action: Reject

Panel Statement: The requirements of 250.104(A) apply to complete metallic water piping systems. Where there is no complete metallic water piping system, then the requirements of 250.104(B) would apply for those portions of isolated metal water piping system likely to become energized.

Number Eligible to Vote: 15
Ballot Results: Affirmative: 15

Then the comment that was made that the bonding is done based on the largest overcurrent device in the panel.
Just how is a branch circuit or feeder that is not connected to the piping system likely to energize anything?

Maybe we should reconsider just how electrodes are installed after all the power company connects to the same earth that we connect to and they use a very high voltage that can carry some mega amps. Here we have both the premises wiring and the power company connecting to the same thing which would be a lot more likely to energize something than a circuit in a raceway or cable in the same area as a metal water pipe.

 

[M. D.]

I just simply said that after reading this thread it is obvious that some just don?t have any understanding of the bonding procedure so they just make up their own rules as they go along........

Not sure that first post said all that ,.. referring to " some ",.. you're really talking mostly about David ,. right??:grin:

 

[jwelectric]

Not sure that first post said all that ,.. referring to " some ",.. you're really talking mostly about David ,. right??:grin:

No I am addressing the old idea of how things are to be bonded.

 

[jwelectric]

No I am addressing the old idea of how things are to be bonded.

Edited to add:

Old ideas die hard and the concept they sometimes leave behind live on forever.

The old idea that any and all metal piping systems are to be electrically continuous is as strong today as it was in early 1990s when it was removed from the electrical code. The NEC has no control over the installation of the piping systems in any building therefore can not mandate that they be electrically continuous.
No electrician, homeowner, general contractor or inspector is expected to assure that the plumber has installed a metal piping system that is electrically continuous.

The idea that something that is bonded and in contact with earth is an electrode holds no merit. There are many installations where gas appliances are supplied by a remote tanks with the pressure vale located at the tank and copper tubing buried to the building.
Does the equipment grounding conductor that is bonded to the appliance make that gas lines an electrode?
If CSST pipe is used for the connection to the appliance would the #6 required by the CSST make this same copper tubing an electrode?

I can understand why it would be a good idea to bond the old galvanized pipes when it was allowed to run the SE conductors to a panel in the middle of the house but I just can?t see it today.

I can?t see how a circuit in a metal raceway could ever energize a pipe. Should the metal raceway be installed correctly (by code) and there was a fault to the metal pipe would not the overcurrent device open?

How could any conductor encased in a nonmetallic raceway or cable ever energize a pipe?

If it was likely for either of these raceways of cables to energize a metal water pipe would the codes even let them be installed?
Would any of the Nationally Recognized Testing Laboratories put their label on any of these raceways if they were likely to fail?

If the circuit is connected to an electrical component that is attached to the metal pipe there is a likelihood that that pipe could become energized just as with the metal around every other piece of metal electrical equipment and just like any other piece of electrical equipment the equipment grounding conductor does the bonding.

It is the old concepts that still live today that I disagree with. My post was directed toward these old ideas not toward any person.

 

[dnem]

post #87
The idea that something that is bonded and in contact with earth is an electrode holds no merit. There are many installations where gas appliances are supplied by a remote tanks with the pressure vale located at the tank and copper tubing buried to the building.
Does the equipment grounding conductor that is bonded to the appliance make that gas lines an electrode?
If CSST pipe is used for the connection to the appliance would the #6 required by the CSST make this same copper tubing an electrode?

Conceptually/philosophically you are, of course, totally right, but ?..

post #32
I've always wondered how one instructs a non-isolated bonded sprinkler piping system to not behave as a grounding electrode?

post #44
The electrons know the difference.

Calling the sprinkler an electrode holds no merit. . But it doesn?t have ears to hear what you call it. . I can't beat up on the fire marshall too badly because how exactly is general bonding electrically [not code speak but movement of electrons] different from electrode ?

Of course there?s usually 2 sides to any story and I have in mind a good point that would support what you?re saying:
When you connect all this metal together, electrically they are all the same thing, the same potential. . And if you connect your equipment ground into the grounding bar of one panel or it gets connected to the bar of a different panel, it?s the same thing. . That?s the whole reason they call pool bonding equipotential because it?s all the same. . Equipment ground, equipotential, general bonding, they all create equality and the point chosen to connect into the system is not better or worse, it?s all the same.
BUT
Electrode is different. . Electrode grounding has the primary responsibility to protect against sharp spikes of overvoltages [lightning, downed highvoltage power lines, primary to secondary transformer shorts]. . Lightning, and other voltage spikes, do not follow all metallic paths equally. . If it has to enter a building and snake around thru the steel rafters before it gets to the #4 bonding wire to the sprinkler, it will find the sprinkler less attractive than if it has a 250kcmil ran directly to the service disconnect. . Now if the lightning hits the building directly, all bets are off. . Overvoltage spikes are also susceptible to the choke effect of bending and looping. . 250.4(A)(1)FPN is a lot more applicable to lightning tracking down an electrode conductor than it is to an equipment ground that?s zipzagging around thru a control panel. . Tthat does mean that I haven't seen lightning fried control panels, I have. . It's just more applicable to lightning.

For the installation that started this thread, on my last stop I suggested to the contractor that he not bond the sprinkler to either the service enclosure or to the building steel nearby. . I pointed in the opposite direct of the service, to a spot where the sprinkler was near the building steel. . That should both satisfy the NFPA 13 electrode concerns of the fire marshall and also make it harder for lightning that?s tracking into the building thru the service and finding the sprinkler to be a ?tasty snack?.

post #87
Old ideas die hard and the concept they sometimes leave behind live on forever.

The old idea that any and all metal piping systems are to be electrically continuous is as strong today as it was in early 1990s when it was removed from the electrical code. The NEC has no control over the installation of the piping systems in any building therefore can not mandate that they be electrically continuous.
No electrician, homeowner, general contractor or inspector is expected to assure that the plumber has installed a metal piping system that is electrically continuous.

I agree with your thought that old ideas die hard and that making all pipes electrically continuous is an old idea. . What I don?t agree with is your feeling about the role of the equipment ground in 250.104(B).

post #87
I can?t see how a circuit in a metal raceway could ever energize a pipe. Should the metal raceway be installed correctly (by code) and there was a fault to the metal pipe would not the overcurrent device open?

How could any conductor encased in a nonmetallic raceway or cable ever energize a pipe?

Correct installation don?t protect against something like an open junction box with pulled-out conductors. . That's why the "circuit that is likely to energize" wording is more applicable to runs that have junction boxes.

post #87
If it was likely for either of these raceways of cables to energize a metal water pipe would the codes even let them be installed?

Yes, that?s the reason for the addition steps that need to be taken in 250.104(B)

post #87
Would any of the Nationally Recognized Testing Laboratories put their label on any of these raceways if they were likely to fail?

It?s not the raceway itself that?s of greatest concern.

post #87
If the circuit is connected to an electrical component that is attached to the metal pipe there is a likelihood that that pipe could become energized just as with the metal around every other piece of metal electrical equipment and just like any other piece of electrical equipment the equipment grounding conductor does the bonding.

But the difference is that there is direct contact between the component and the attached metal pipe so the equipment ground provides the path for both component and pipe.

If the component/circuit equipment ground is sufficient regardless of whether or not the component is in physical contact with the pipe, then what is the reason for 250.104(B) ? . There are four sentences in 250.104(B). . If your position was right, there would be a need for only sentence #3: "The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means.". . That's it ! . 250.104(B) would stop there ! . There's no need for wording about "service equipment", about "electrode conductor where of sufficient size", about "sized according to 250.122".

There's more to 250.104(B) than you are saying. . There is more than just determining if there is an equipment ground present with the hot that is "likely to energize". . The physical contact between component and pipe is considered.

post #87
No electrician, homeowner, general contractor or inspector is expected to assure that the plumber has installed a metal piping system that is electrically continuous.

That is a good point. . And that's why I said:
As a side note, I know that the sprinkler pipe bond to one of the pipes will be of questionable value beyond that one stick of pipe because of the nonconductive fittings. . But there will be some bonding accomplished thru the impure water that will soon be in the pipe [wet system]. . "Likely to be energized" ? . I don't know. . Will one bond to steel be enough ? . I don't know.

With nonconductive fittings, 250.104(B) is like throwing a dart. . You hit somewhere on the target but you don't cover the whole target.

And I think we'll both agree that covering the whole target isn't either required or intended by the NEC.

 

[jwelectric]

David

Could you please explain to me what bonding one piece of pipe with a 3/0 copper conductor knowing that it has no current carrying ability beyond itself and it possibly being less than one percent of the system would accomplish?

Why do you think that the Code Making Panel made the statement they did in the proposal posted above?

I have a ? inch rigid conduit buried 36 inches deep going out to a piece of electrical equipment in the back yard. Do I need to bond this conduit with a #6 as it fits the description found in 250.52(A)(5)(a) and installed as outlined in 250.53(G)?

As outlined in 250.118 the conduit itself is an equipment grounding conductor so does that fact make the conduit an electrode?

If the transformer shorted from primary to secondary or a high voltage line fell across a service drop would the higher voltage cause the NM cable to energize a metal pipe?

My question is why would anyone bond something that isn?t electrically continuous with such a large conductor for in the first place?

Is it the train of though a short time occurrence such as a spike or lightning the bonding would bring everything to the same touch potential? If nothing is connected to something that is metal how is the spike or lightning going to energize it?
If the thought is the touch potential or that everything becomes somehow mysteriously energized wouldn?t we need to ensure that the entire sprinkler system be electrically continuous?

Some things I just have a hard time understanding.

 

[kkwong]

Dnem-What classification is the sprinkler system?

I can't speak for the rest of the country, but every sprinkler system that conforms to NFPA 13 not any of the derivitives i.e. 13-R or 13-D, have a seperate tap from the municipal supply independant of the domestic supply. This has to do with the requirements for fire flow for the occupancy under construction and depending on those requirements domestic supply won't come close to the required flow.

The underground piping of the system is traditionally done in plastic with the transition coupling being ductile iron and the sprinkler piping being sched 40 iron.

If wiring is coming in contact with the sprinkler system, this is also in violation of NFPA 13 and would be ordered fixed by any fire department.

As for bonding the sprinkler riser....I have never seen it and though I don't doubt it's allowed, would have to have a long talk with the EI, the Fire Marshal and the Head Building Official...

 

[M. D.]

David

Could you please explain to me what bonding one piece of pipe with a 3/0 copper conductor knowing that it has no current carrying ability beyond itself and it possibly being less than one percent of the system would accomplish?...........

You must have missed this ,.I love this logic if you can't tell which one ,.. just pick the largest one ...

Quote:
Originally Posted by dnem
There's no clear way to determine if such a circuit is present and which circuit is the "likely" one. . We always handle 250.104(B) the same way. . Ignore your service disconnect size, pick the largest OCPD in the building [feeder or branch circuit] and size according to that.

or this

As I said before, in the real world, the largest breaker in most panels [excluding the main(s)] is usually 300a or less. . 250.122 for 300a is only #4 which is common everyday stuff and also fits in your standard size pipe bonding clamp.

If the contractor wanted to dispute our "use the largest breaker" direction based on the fact that the run has no junction boxes, I wouldn't have any objection to logic. . If the second largest breaker is 300a or less, he pulls out a spool of #4 and everybody's happy

 

[dnem]

Mike,

Before I comment on anything you posted, I want to make sure that were in agreement on what all of the "pieces parts" of grounding are. . Because if you intermix the categories, all you end up with is confusion.

1] electrode grounding [main coverage in 250part3, 250.50-250.70]
2] equipment grounding [main coverage in 250parts6+7, 250.110-250.148]
3] equipotential bonding [main coverage in 547.10,680.26,+682.33]
4] general bonding [main coverage in 250part5, 250.90-250.106]

and this thread concentrates on subdividing general bonding into 2 subcategories
a] continuous electrically conductive water pipe system [250.104(A)]
b] not continuous electrically conductive water pipe system and non-water systems [250.104(B)]
c] isolated structural steel [250.104(C)] is a third subcategory which isn't being discussed at all

For keeping it clear what I'm referring to, I'm going to keep referring back to these categories.

Could you please explain to me what bonding one piece of pipe with a 3/0 copper conductor knowing that it has no current carrying ability beyond itself and it possibly being less than one percent of the system would accomplish?

By T250.66, 3/0 for an over 1100kcmil service would be appropriate for a connection to an electrode [which I listed above as category #1]. . It would also be appropriate for a general bonding connection to a continuous electrically conductive water pipe system [which I listed above as category #4 and subcategory a, 250.104(A)].

It would not be appropriate for a general bonding connection to a non-continuous electrically conductive water pipe system or non-water system [which I listed above as category #4 and subcategory b, 250.104(B)].

When you say "one piece of pipe", you're talking category #4 + subcategory b, 250.104(B).

By T250.122, for this one piece of pipe you could be bonded with a #4gauge as long as the "likely to energize" circuit is no larger than 300amp. . It's extremely uncommon to distribute runs protected at over 300a that also include a junction box in the run.

So you're bonding with a #4gauge because of the category and subcategory.

Why do you think that the Code Making Panel made the statement they did in the proposal posted above?

I have a ? inch rigid conduit buried 36 inches deep going out to a piece of electrical equipment in the back yard. Do I need to bond this conduit with a #6 as it fits the description found in 250.52(A)(5)(a) and installed as outlined in 250.53(G)?

" going out to a piece of electrical equipment in the back yard"
and obviously containing circuit conductors to that equipment does not fit the description in 250.52(A)(5)(a). . That ? is a raceway and can be used as an equipment ground. . You have to go to Article300 for installation. . 250.52 applies only to electrode grounds.

Do the electrons flow differently because you label the pipe differently ? . Of course not. . But the NEC says one is an equipment ground and the other is an electrode ground and you install them differently and for different purposes.

As outlined in 250.118 the conduit itself is an equipment grounding conductor so does that fact make the conduit an electrode?

Never is it both equipment ground and electrode ground ! . It is always only categorized as one or the other depending on usage and is installed according.

If the transformer shorted from primary to secondary or a high voltage line fell across a service drop would the higher voltage cause the NM cable to energize a metal pipe?

"the transformer shorted from primary to secondary or a high voltage line fell across a service drop"
would be handled by an electrode conductor that is grounded to an electrode.

"cause the NM cable to energize a metal pipe"
I'm assuming this is your backyard ?" pipe, which is an equipment ground. . The equipment grounding conductor ?" pipe is not there for large overvoltage spikes.

The electrode ground is installed to handle your high voltage spike and is sized accordingly. . The equipment ground is installed to handle your NM short or fault and is sized accordingly. . Don't intermix them.


I'm assuming your next statement is no longer looking at the ?" conduit outside but we're back to the inside pipe, probably sprinkler.

My question is why would anyone bond something that isn’t electrically continuous with such a large conductor for in the first place?

"isn’t electrically continuous"
non-continuous electrically conductive water pipe system or non-water systems, category #4 and subcategory b, 250.104(B)
"with such a large conductor"
250.104(B) sends you to 250.122. . You usually get a 4gauge. . That's not large.

Is it the train of though a short time occurrence such as a spike or lightning the bonding would bring everything to the same touch potential? If nothing is connected to something that is metal how is the spike or lightning going to energize it?
If the thought is the touch potential or that everything becomes somehow mysteriously energized wouldn’t we need to ensure that the entire sprinkler system be electrically continuous?

You're mixing 2 things that should not be mixed. . The "spike or lightning" is handled by the electrode ground [250.50-250.70]. . The non- electrically continuous sprinkler pipe is handled by general bonding [250.104(B)] and protected from the "circuit likely to energize", not from spikes or lightning. . Don't size the bonding for the non- electrically continuous sprinkler pipe with lightning in mind. . When the code goes to T250.66, it's addressing stuff like lightning. . Size it with "circuit likely to energize" in mind. . You'll be in T250.122.


What makes this tough is that all of these grounding categories all tie together at the service and are electrically continuous. . There is electrical continuity between electrode grounding, equipment grounding, equipotential bonding, and general bonding.

In real life, the distinction between the categories of grounding doesn't prevent lightning for ever tracking down any given path and thru the sprinkler pipes. . But that still doesn't allow you to blur the categories when you are installing the different requirements.

For good or bad, this is how the NEC is set-up. . The fact that all this grounding interconnects doesn't allow you to blur the categories when you are installing the different requirements.

 

[jwelectric]

Where are you getting the idea of a #4 to the sprinkler pipe from?

What does a junction box have to do with the way something is bonded?

Are you saying that we bond and size the conductor based on a junction box?

 

[iwire]

David, have you ever tried to be a least a little concise?

I can't for the life of me follow those long posts.

 

[jrannis]

David, have you ever tried to be a least a little concise?

I can't for the life of me follow those long posts.

I would have taken me a year to post all of that

 

[LarryFine]

I would have taken me a year to post all of that

It would only take me six months to read it. :wink:

 

[jwelectric]

It would only take me six months to read it. :wink:

Well I did read it...don't understand much of it but I did read it

 

[dnem]

David, have you ever tried to be a least a little concise?

I can't for the life of me follow those long posts.

I was responding to specific statements made by Mike Whitt.
What good is concise if what I say is vague ?

If you want concise, just read the next quote below. . If it doesn't clear everything up, they concise isn't what's needed. . Sometimes nothing will do the job except a full explanation.

Before I comment on anything you posted, I want to make sure that were in agreement on what all of the "pieces parts" of grounding are. . Because if you intermix the categories, all you end up with is confusion.

1] electrode grounding [main coverage in 250part3, 250.50-250.70]
2] equipment grounding [main coverage in 250parts6+7, 250.110-250.148]
3] equipotential bonding [main coverage in 547.10,680.26,+682.33]
4] general bonding [main coverage in 250part5, 250.90-250.106]

and this thread concentrates on subdividing general bonding into 2 subcategories
a] continuous electrically conductive water pipe system [250.104(A)]
b] not continuous electrically conductive water pipe system and non-water systems [250.104(B)]
c] isolated structural steel [250.104(C)] is a third subcategory which isn't being discussed at all

Where are you getting the idea of a #4 to the sprinkler pipe from?

What does a junction box have to do with the way something is bonded?

Are you saying that we bond and size the conductor based on a junction box?

Well I did read it...don't understand much of it but I did read it

You're questions make it obvious that you didn't read the whole thread and since I have to be concise, I'll say:

Read the thread [except posts #57 + #58]. . The answers have been discussed.

 

[jwelectric]

I did read the entire thread not once but twice and I disagree with a lot of what is being said about bonding the sprinkler system in this building.

First the bonding or grounding of a piece of metal that is in contact with earth does not make that piece of metal an electrode.
If this was true then every metal conduit that is underground would be an electrode.

Second this idea of bonding a metal pipe based on Table 250.66 when this metal pipe is not 100% metal or to say it another way, electrically continuous is plain stupid.

Third to think that a water pipe could be energized just because there is a junction box close by is even more stupid that the second thought.

Forth to think that the hot and cold water lines constitute two different potable water systems if even crazier than the first three thoughts.

And lastly, when I read that post about bonding a piece of metal pipe based on the largest overcurrent device in a panel that supplied a feeder I knew that someone had dropped off the edge.

 

[dnem]

I'll be concise.

I did read the entire thread not once but twice and I disagree with a lot of what is being said about bonding the sprinkler system in this building.

Disagree, I can understand.
Asking questions that have already been answered [as you did in your last post], I didn't understand.

First the bonding or grounding of a piece of metal that is in contact with earth does not make that piece of metal an electrode.
If this was true then every metal conduit that is underground would be an electrode.

If someone other than you made that claim on this thread, please post the post#, I'd like to read it.

Second this idea of bonding a metal pipe based on Table 250.66 when this metal pipe is not 100% metal or to say it another way, electrically continuous is plain stupid.

Has anybody said that a pipe that "is not 100% metal" should be bonded "based on Table 250.66" ?

Once again, if someone made that claim on this thread, please post the post#, I'd like to read it.

Third to think that a water pipe could be energized just because there is a junction box close by is even more stupid that the second thought.

How about you offering a definition of "the circuit that is likely to energize the piping". . Don't dismiss how other people apply that phrase unless you have an alternative.

Forth to think that the hot and cold water lines constitute two different potable water systems if even crazier than the first three thoughts.

It's only 2 different systems if there is no bonding jumper between them. . If someone made that claim on this thread, please post the post#, I'd like to read it.

And lastly, when I read that post about bonding a piece of metal pipe based on the largest overcurrent device in a panel that supplied a feeder I knew that someone had dropped off the edge.

How about you offering a definition of "the circuit that is likely to energize the piping". . Don't dismiss how other people apply that phrase unless you have an alternative.

I think I'm getting "a hang" on this concise thingy.