250.104(B) Other Metal Piping 2014 NEC

[Dennis Alwon]

I am looking for feedback on this article. As I read the article no bonding is necessary on a gas pipe if, for instance, the only gas appliance is a water heater.

It appears that the cmp inadvertently or not, defined likely to be energized. What do you all think

(B) Other Metal Piping. If installed in, or attached to, a building or structure, a metal piping system(s), including gas piping, that is likely to become energized shall be bonded to any of the following:
(1) Equipment grounding conductor for the circuit that is likely to energize the piping system
(2) Service equipment enclosure
(3) Grounded conductor at the service
(4) Grounding electrode conductor, if of sufficient size
(5) One or more grounding electrodes used The bonding conductor(s) or jumper(s) shall be sized in accordance with 250.122, using the rating of the circuit that is likely to energize the piping system(s). The points of attachment of the bonding jumper(s) shall be accessible.

 

[Hendrix]

I am looking for feedback on this article. As I read the article no bonding is necessary on a gas pipe if, for instance, the only gas appliance is a water heater.

It appears that the cmp inadvertently or not, defined likely to be energized. What do you all think

I think that "likely" is the key word. It's a judgment call.

 

[MasterTheNEC]

Dennis,

I can only offer my opinion to this.

From my reasoning, any time an actual branch circuit wiring is directly connected to a piece of electrical equipment that is supplied and has metal piping as well associated with the equipment, that it is likely to become energized. It was never intended that if a piece of nonmetallic-sheathed cable (Type NM Cable) that may come in contact with metal gas piping (for example, laying across it at some point) that it be considered "likely" to become energized. I can assure you that was not CMP-5's intent.

It is my opinion again that the interconnection of systems where the piping systems and the electrical system are commonly linked does increase the likelyhood of being energized. This is why the use of the EGC to meet the bonding is acceptable since it is common also to the location.

But I also agree that the term "likely" is subjective to the installation and interpretation of the AHJ depending on the conditions that are present in their judgement but using the reasoning above is the general guide that I hope AHJ's would consider. Just having a piece of NM Cable touching a metal gas line "sparks" debate over it's potential to energize the piping system and I just don't believe that is the case in my opinion.

 

[bphgravity]

This is something that needs to be determined on a case-by-case basis. I can imagine scenarios where gas piping is installed and not likely to be energized, thus not required to be bonded. But, when in doubt - BOND! Sometimes, the bonding is already accomplished by the conductive materials used to support the gas piping to the structure. This is especially true in buildings with metal structural framing that is already bonded due to Section 250.52(A)(2) or 250.104(C). Gas piping supported by the metal framing with metal hangers or metal straps is likely to be effectively bonding whether it needed to be or not...

 

[mwm1752]

IMO - The reference in this code section to likely to become energized depends on if there is a gas appliance on the premises some where that is served with a branch circuit. If that is the case you would be covered with an EGC that is installed with the branch circuit. Some may say that if the premises has electrical service the likely to become energized is present.
The reference to likely to become energized also exist in ( C) structural metal. Are we talking electrical equipment attached to such exposed metal. So take for instance you mount a non metallic enclosure to a beam - there is no continuity of metal parts existing inside the non metallic enclosure to the beam - Is a bond neccesary from inside the enclosure to the beam?

 

[MasterTheNEC]

This is something that needs to be determined on a case-by-case basis. I can imagine scenarios where gas piping is installed and not likely to be energized, thus not required to be bonded. But, when in doubt - BOND! Sometimes, the bonding is already accomplished by the conductive materials used to support the gas piping to the structure. This is especially true in buildings with metal structural framing that is already bonded due to Section 250.52(A)(2) or 250.104(C). Gas piping supported by the metal framing with metal hangers or metal straps is likely to be effectively bonding whether it needed to be or not...

Agreed. We just have to also remember that in many cases the supports may be nonconductive or nonmetallic in nature to aid in not providing damage to the piping system as a whole and would not accomplish the bond needed. As you stated, it ends up being a judgement call from the condition of use and a true examination (on site) of the likely nature.

But I do agree 100%....when in doubt BONDING serves distinct purpose. Let's just make sure we don't make them do it if an NM Cable touches a gas piping along its installation and that is in my opinion not the intent of the term "likely".

 

[rcarroll]

I don't look for a bond unless the yellow CSST is installed.
Furnace by EGC. Done. :thumbsup:

 

[charlie b]

It appears that the cmp inadvertently or not, defined likely to be energized.

I am not sure I understand this comment. I see nothing in the wording of the code that explains or defines what is meant by likely to be energized. All I see is a set of places we could bond, if bonding were required (i.e., if the pipe is likely to be energized). What are you asking for here? :?

 

[Smart $]

I am not sure I understand this comment. I see nothing in the wording of the code that explains or defines what is meant by likely to be energized. All I see is a set of places we could bond, if bonding were required (i.e., if the pipe is likely to be energized).

Compare to previous edition....

(B) Other Metal Piping. If installed in, or attached to, a
building or structure, a metal piping system(s), including
gas piping, that is likely to become energized shall be
bonded to the service equipment enclosure; the grounded
conductor at the service; the grounding electrode conductor,
if of sufficient size; or to one or more grounding electrodes
used. The bonding conductor(s) or jumper(s) shall be
sized in accordance with 250.122, using the rating of the
circuit that is likely to energize the piping system(s). The
equipment grounding conductor for the circuit that is likely
to energize the piping shall be permitted to serve as the
bonding means. The points of attachment of the bonding
jumper(s) shall be accessible.

 

[charlie b]

Compare to previous edition....

Maybe I need more coffee this morning, but the two versions look the same to me, other than one being in paragraph format and the other being in list format. Neither has any words that convey the message, "a pipe shall be considered likely to become energized if it is . . . ."

 

[petersonra]

I don't know that they have "defined" likely at all. They do appear to have clarified that the EGC for a BC feeding a device can serve as the bonding means. Why they thought that was necessary is a bit of a mystery to me.

It does somewhat imply that if a device is fed by both a BC and a piping system that the piping system is likely to become energized, but that the EGC should take care of the required bonding. It is not like it says this is the only case where something is "likely" to become energized.

 

[Smart $]

Maybe I need more coffee this morning, but the two versions look the same to me, other than one being in paragraph format and the other being in list format. Neither has any words that convey the message, "a pipe shall be considered likely to become energized if it is . . . ."

That is correct. I believe Dennis is reading between the lines... and the newer version has more lines. :lol:

IMO, proper premises wiring would never make any piping system "likely to be energized". Granted, such system may become energized through a fault... but that is a radically different concept.

 

[Dennis Alwon]

Maybe I need more coffee this morning, but the two versions look the same to me, other than one being in paragraph format and the other being in list format. Neither has any words that convey the message, "a pipe shall be considered likely to become energized if it is . . . ."

In the past many authority having jurisdiction's felt that as long as nm cable could possible run across the gas piping and inadvertently touch the piping then it was likely to be energized. Reading between the lines as Smart stated it looks like they are saying that likely to be energized happens when a branch circuit feeds a gas appliance.

I do believe that a bond is not required in all cases but, if the equipment grounding conductor from a 15 or 20 amp circuit is sufficient for bonding, then why would I have to use T 250.66 if there is no circuit that feeds any gas equipment? Personally I don't think it is necessary but going by what bphgravity stated

But, when in doubt - BOND!

you would need to use T. 250.66---NO?

 

[Dennis Alwon]

That is correct. I believe Dennis is reading between the lines... and the newer version has more lines. :lol:

IMO, proper premises wiring would never make any piping system "likely to be energized". Granted, such system may become energized through a fault... but that is a radically different concept.

You got it....

Imagine this-- gas furnace is wired with 20 amp cir. The gas pipe is installed using a dielectric fitting-- now what- 250.66?

 

[Smart $]

... Personally I don't think it is necessary but going by what bphgravity stated you would need to use T. 250.66---NO?

Whether you use T250.66 or -122, what OCPD or conductors are you going to base the bond size on???

 

[Dennis Alwon]

Whether you use T250.66 or -122, what OCPD or conductors are you going to base the bond size on???

I don't see where we are allowed to use anything other than 250.66 which is based on the service conductors. A 200 amp service generally means #4 copper. This is, of course, assuming no branch circuits feed it.

 

[Smart $]

I don't see where we are allowed to use anything other than 250.66 which is based on the service conductors. A 200 amp service generally means #4 copper. This is, of course, assuming no branch circuits feed it.

250.104(B) specifically states 250.122.

 

[Dennis Alwon]

250.104(B) specifically states 250.122.

Yes that is only when the gas appliance is fed with a branch circuit. Many authority having jurisdiction's want the piping bonded even if there isn't a gas appliance that needs a branch circuit. Where do we get reprieve from 250.66

 

[Smart $]

Yes that is only when the gas appliance is fed with a branch circuit. Many authority having jurisdiction's want the piping bonded even if there isn't a gas appliance that needs a branch circuit. Where do we get reprieve from 250.66

I don't see where 250.104(B) says the piping system has to be connected to an appliance or other piece of utilization equipment... nor do I see where you must bond per 250.66 if not so connected.

 

[Dennis Alwon]

I don't see where 250.104(B) says the piping system has to be connected to an appliance or other piece of utilization equipment... nor do I see where you must bond per 250.66 if not so connected.

I get it but I think I am assuming that since water pipe and structural metal must use 250.66 that the gas pipe would (should) follow that logic.