NFPA 70 + NFPA 13 conflict

[M. D.]

David , in my opinion your office confuses "possible" , not the word plausible ,...rather the word possible with the word "likely".

Perhaps I have not been as passionate as Mr. Whitt but I agree ,more or less ,. with his assessment and thought I had expressed my disapproval of this rule your office has created. There may be a case where there is no circuit likely to energize the sprinkler pipe or that it may be as small as a #14 , even though there is a 300 amp breaker in the building ,.. IMO your rule would not stand up if challenged and I hope it does get challenged ,..I have nothing against you ,..I just don't like these types of "rules"

 

[dnem]

There may be a case where there is no circuit likely to energize the sprinkler pipe or that it may be as small as a #14 , even though there is a 300 amp breaker in the building

You have to decide what it is about a circuit that would make it likely to be energized. . I'm stated that the existence of a junction box provides an opening in an otherwise continuous conduit. . I'm open to hear another option. . But it seems that your position is that there is no likely to energize circuit. . And yet 250.104(B) is in the code and there for a reason.

IMO your rule would not stand up if challenged and I hope it does get challenged ,..I have nothing against you ,..I just don't like these types of "rules"

For it to be challenged, there would have to be provided the correct application of that paragraph.

Our rule probably is a problem because we don't address what makes something "likely". . I've suggested a junction point but until now we've been enforcing based on largest feeder or branch circuit with no mention of junctions. . A solid conduit run isn't likely to energize, and actually quite unlikely to energize when you consider that there is an equipment ground in the conduit.

I'm going to push the junction point/box thought in my office.

But the other side of the argument is that 99.9% of the time there are no runs over 300a that have junction points [pull points, yes, wire junction points, no]. . So this is an easy to add safety feature consisting of 2 clamps and a #4 wire to the nearby building steel.

 

[M. D.]

.....I'm going to push the junction point/box thought in my office.....
.

I do not for the life of me understand this approach ,..you have an answer looking for a question.. the scenario you have described is not at all likely ,..

Likely:
having a high probability of occurring or being true : very probable

<rain is likely today>


Probable:
1 : supported by evidence strong enough to establish presumption but not proof
<a probable hypothesis>

2 : establishing a probability <probable evidence>

3 : likely to be or become true or real
<probable outcome>

We, like everybody else, have no way to determine what is "likely". . Is it just possible or is it likely ? . Who knows.

I have a dictionary and likely and possible are two different words that do not have the same meaning and the NEC used the word likely.

Your largest feeder or branch circuit has the ability to snake around thru the building wherever you want to run it. . At installation or anytime in the future, anybody can leave off a junction box and maybe pull out a joint and walk away.

And this is highly probable this is possible, I suppose ,but not likely

 

[dnem]

MD

If I agreed with every word that you've said, it still wouldn't address the central point. . It seems that your position is that there is no likely to energize circuit. . And yet 250.104(B) is in the code and there for a reason.

 

[M. D.]

I think most of the time , with few exceptions, the circuit likely to energize is the circuit run to it ,..be it a flow switch or an electric motor and that the equipment grounding is all the bonding required. Much like how the gas pipe is treated

 

[jwelectric]

If a metal raceway is installed properly then it is bonded and could not energize anything.

If a junction box is installed properly then it is closed and bonded and could not energize anything.

The text found in 250.104(B) allows for the EGC of the circuit likely to energize to be the bonding conductor. If the EGC is of the circuit likely to energize is allowed to do the bonding, wouldn?t this mean that the circuit is connected to the pipe in some way or does the code allow for EGC to be spliced to bond to other objects?

The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means.

I suppose it wouldn?t hurt anything to run an equipment bonding jumper from every junction box in the building to the sprinkler pipe to conform with the sentence above but we might have a problem finding somewhere to install all these clamps to the pipe.

 

[M. D.]

what if we had this situation

In electric fire pump installations, the equipment grounding conductor is a wire or metal raceway. The metal sprinkler piping is connected to the pump's metal case, which is bolted to the electric motor with a dielectric coupling so that the sprinkler piping is not in electrical contact with the grounding system.

My next question is ,..O.K. then so what circuit(s) is now likely to energize this piping .. the answer could very well be,.. none. No circuit is likely to energize the piping . Not saying that bonding it or a piece of it here and there is a bad idea just not required if it were wouldn't it have to made electrically continuous?