Electrical Bonding- DWV

[Nat Palmer]

Who calls out metal drain waste vent piping for not being bonded? Especially in mixed metal/plastic systems.

_Nat

[Nat Palmer]

NEC 250104(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that is likely to become energized shall be bonded...

I have not yet called this out but I was looking at some copper dwv pipe and started thinking that if we're concerned with supply piping being electrified wouldn't drain pipe be just as hazardous? Has anyone thought about this? Have I missed a code exception excluding dwv pipe?

_Nat

[Corey Friedman]

NEC 250104(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that is likely to become energized shall be bonded...

I have not yet called this out but I was looking at some copper dwv pipe and started thinking that if we're concerned with supply piping being electrified wouldn't drain pipe be just as hazardous? Has anyone thought about this? Have I missed a code exception excluding dwv pipe?

_Nat

Hello Nat,

…. "is likely to become energized"… is a big part of this section. What is in the surrounding area that would likely cause the DWV to be energized (that you can see)? During construction / remodeling this is easy for the code cops to see and decide. It is also important to recognize that the local Building Official and/or AHJ make the interpretation as to what "is likely to become energized" means and enforce it accordingly in their jurisdictions.

If you feel that bonding a conductive DWV would be beneficial to your client, recommend it. I would not suggest recommending it just because it is in the current NEC.

I don’t recall when "is likely to become energized" or the related section showed up but I’m thinking it was the 1999 NEC. Would you be making the same recommendation for homes built under older NEC requirements?
Just some thoughts.

Sincerely,

Corey Friedman

[Jerry Peck]

…. "is likely to become energized"… is a big part of this section.

In looking back to the 1996 NEC on my computer (the oldest one I have on my computer) the term is "that may become energized", not "is likely to".

That said, though, a better reference to apply would be (again, from the 1996 NEC) 250-80(a) instead of 250-80(b): (bold and underlining is mine)
- 250-80. Bonding of Piping Systems and Exposed Structural Steel.
- - (a) Metal Water Piping. The interior metal water piping system 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 shall be sized in accordance with Table 250-94 and installed in accordance with Sections 250-92(a) and (b). The points of attachment of the bonding jumper shall be accessible.
- - - Exception: In buildings of multiple occupancy, where the interior metal water piping system for the individual occupancies is metallically isolated from all other occupancies by use of nonmetallic water piping, the interior metal water piping system for each occupancy shall be permitted to be bonded to the panelboard or switchboard enclosure (other than service equipment) supplying that occupancy. The bonding jumper shall be sized in accordance with Table 250-95.
- - Where there is a separately derived system using a grounding electrode as covered in Section 250-26(c)(3), the nearest available point on the interior metal water piping system in the area served by the separately derived system shall be bonded to the grounded conductor of the separately derived system. The bonding conductor shall be sized in accordance with Table 250-94 for the derived phase conductors and installed in accordance with Sections 250-92(a) and (b). The points of attachment of the bonding conductor shall be accessible.
- - (b) Other Metal Piping. Interior metal piping that may become energized 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 shall be sized in accordance with Table 250-95 using the rating of the circuit that may energize the piping.
- - The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means.
- - - (FPN): Bonding all piping and metal air ducts within the premises will provide additional safety.

Note that there are, in older homes using cast iron or galvanized for DWV, *two* "interior metal water piping" systems: the supply and the DWV.

If you have ever been in a crawlspace and crawled across an energized cast iron waste line you will understand why. :)

I have never found an exception which exempts the interior metal DWV system from that bonding requirement.

[H.G. Watson, Sr.]

Metal DWV is not water piping (sub-paragraph a), it is WASTE piping, but if it may become energized, it fell under the category of other metal piping (sub-paragraph b) If the circuit which may energize the other metal piping contained an EGC, was allowed to be considered the bonding means, otherwise and should have been bonded under 1996 NEC.

Interior metal water piping systems include potable water piping, sprinkler water piping, hydronic heat piping, gray water recycling system piping, etc. interior to the structure.

[Jerry Peck]

Interior metal water piping systems include potable water piping, sprinkler water piping, hydronic heat piping, gray water recycling system piping, etc. interior to the structure.

H. G.,

Do you have an interpretation on that?

If the metal piping carries "water", and "waste" piping does indeed carry "water", then it is "water" piping.

The code does not specify that it must be one of the restricted "water" systems you stated, the code only states "interior water piping".

Aaron,

Those ancient texts were quoted as that was the direction the previous posts were headed ... to the ancient wonders of the world and electricity.

During a recent discussion with contractors about exemptions from permits, the repair of leaks in plumbing systems are exempt from permits, the repair of leaks in refrigerant systems are exempt from permits, the repair of leaks from electrical systems ... ancient or otherwise ... repairs of "leaks" from electrical systems :eek: require permits. I know, this was slightly 'drifting off topic' but it applies to your ancient remarks. :p

[H.G. Watson, Sr.]

H. G.,

Do you have an interpretation on that?

If the metal piping carries "water", and "waste" piping does indeed carry "water", then it is "water" piping.

The code does not specify that it must be one of the restricted "water" systems you stated, the code only states "interior water piping".


Mr. Peck,

The onus is not upon me to disprove your erroneous assertion, which is neither supported by the codes presently, nor the historical versions of the electrical, plumbing, mechanical, or building codes.

It is not upon me to prove a negative, nor waste my time disproving your wild assertion and flawed logic. It is you who have made a leap and assertion which is not supported by the codes, nor any past or present version, metal DWV or metalic building sewer is OTHER METALIC PIPING not "water piping".

Water pipes, be them potable or not, are designed to contain water to capacity at pressure for the fluid length of the system circuit.

DWV, Drain-waste-vent systems ARE NOT "water pipes" or "interior water pipe systems". They are plumbing systems, but not all plumbing systems are "water systems". They have "fluid" in common (be it air, NG, water, or waste), not "water" not "under pressure", are gravity based exchange.

The metalic or nonmetalic make-up of either, notwithstanding.

DWV systems are not water piping systems, nor are they made up of "water pipes", they are drain-waste-vent systems, made up of drain-waste-vent "pipes" and fittings, and when designed and working properly are not filled to capacity with fluid water, they transport/exhange fluid drainage/waste and gas (air, methane, etc.).

Metalic DWV, and other metalic piping systems then (1996) and now (2009) are covered under Other Metal Piping, not interior "water piping"; then (1996) and now (2009) can be considered "bonded" via the bonded EGC of the electrical circuit itself that may or likely energize the Other (than water) Metal Piping.

[brian schmitt]

Who calls out metal drain waste vent piping for not being bonded? Especially in mixed metal/plastic systems.

_Nat
if this system is a mixture of metal and plastic it is not a metal pipe system per the experts :D and would not require bonding. pex water piping and copper piping mixed systems would not require bonding either.

[Jerry Peck]

Mr. Peck,

The onus is not upon me to disprove your erroneous assertion,


To the contrary, you are the one stating that another is wrong, it is therefore up to you to provided back up substantiating that assertion when you are requested to document it.


DWV systems are not water piping systems, nor are they made up of "water pipes", they are drain-waste-vent systems, made up of drain-waste-vent "pipes" and fittings, and when designed and working properly are not filled to capacity with fluid water, they transport/exhange fluid drainage/waste and gas (air, methane, etc.).


To the contrary, Aaron's reference below helps document what I am saying, even though Aaron apparently did not bother to read it as he is trying to apply it to support you, but it specifically states otherwise.



The IRC seems to agree with HG:


To the contrary, it agrees with me - see the part which I have underlined and made bold, and red text.



PLUMBING SYSTEM.

Includes the water supply and distribution pipes, plumbing fixtures, supports and appurtenances; soil, waste and vent pipes; sanitary drains and building sewers to an approved point of disposal.


The plumbing system includes all piping, fixtures and components that transport potable water and convey liquid and liquid-borne solid wastes. See “Plumbing.” Devices that treat the water prior to its use are also included.

[Jerry Peck]

if this system is a mixture of metal and plastic it is not a metal pipe system per the experts :D and would not require bonding. pex water piping and copper piping mixed systems would not require bonding either.

Depending on the amount of metallic piping, that would be correct. Installing one plastic fitting into a metallic piping system does not make it no longer a metallic piping system - it simply means one needs to bond around the plastic fitting. :D

[H.G. Watson, Sr.]

On the contrary Mr. Peck.

The OP and those which followed correctly referenced sub paragraph (b) of the current code section.

Although you quoted it (an equal code section from 1996 and included sub paragraph (b) of same), you were the first to assert that others were incorrect, and asserted they should follow sub paragraph (a) which is for metalic WATER piping. You are the one who CLAIMED it was WRONG to apply sub paragraph (b) (other metalic pipe)to metal/conductive DWV and YOU CLAIMED DWV within the structure was "interior metalic WATER pipe".DWV is not "water pipe" it is drain-waste-vent pipe.

The code addresses this (other metal pipe) differently than "water pipe" for good reason, I've already 'splained one of the reasons - that you 'don't get it' as to why empty or less than full and continuously occupied by fluid water makes a difference in what is and is not a "water pipe", than you can't be helped.

It is YOU who corrected others FIRST and INJECTED your unsupported conclusion - it is YOU who bear the burden of supporting your "water pipe" designation, and assertion that sub section (a) of the current or past (1996) NEC applies to metalic DWV, building drain, or building sewer pipe and not sub paragraph (b).

Plumbing pipe does NOT Equate to "water pipe". Fluid does not equate to "water". "Liquid" does NOT equal "water". Plumbing, fluid, and liquid are MORE GENERAL terms which are inclusive of water, but not exclusive of other fluids, liquids, or plumbing pipes. ;).

[Jerry Peck]

Plumbing pipe does NOT Equate to "water pipe". Fluid does not equate to "water". "Liquid" does NOT equal "water". Plumbing, fluid, and liquid are MORE GENERAL terms which are inclusive of water, but not exclusive of other fluids, liquids, or plumbing pipes. ;).

The NEC does not define "interior metal water piping system":


ARTICLE 100 Definitions
Scope. This article contains only those definitions essential to the proper application of this Code. It is not intended to include commonly defined general terms or commonly defined technical terms from related codes and standards. In general, only those terms that are used in two or more articles are defined in Article 100. Other definitions are included in the article in which they are used but may be referenced in Article 100.
Part I of this article contains definitions intended to apply wherever the terms are used throughout this Code. Part II contains definitions applicable only to the parts of articles specifically covering installations and equipment operating at over 600 volts, nominal.


The follow code reference, a "related codes and standards", does:

PLUMBING SYSTEM.
Includes the water supply and distribution pipes, plumbing fixtures, supports and appurtenances; soil, waste and vent pipes; sanitary drains and building sewers to an approved point of disposal.

The plumbing system includes all piping, fixtures and components that transport potable water and convey liquid and liquid-borne solid wastes. See “Plumbing.” Devices that treat the water prior to its use are also included.

[Rollie Meyers]

I have a question, how does one propose to bond cast iron DWV pipe w/ No-Hub bands? :D :D Each section of CI pipe / fittings using No-Hub bands are isolated /insulated from each other.I am not talking about cast iron bell & spigot pipe made up w/ lead & oakum joints.

http://www.plumbingsupply.com/images/nohub_coupling.jpg

[Richard Soundy]

Jerry,

I am by no means a legal expert, but it has always been my understanding when reading codes (like NEC) using the statement of metal "water pipes" and "other pipes" is clearly distinguishable by what is being "carried" by the pipes and not the medium or method of carriage, under pressure or not. Water pipes carry "water" and waste pipes carry "waste".

I am relatively sure that the intent of the NEC quotation of other piping was/is to include DWV within this specific category.

Just my humble opinion regarding this matter.

All the best - Richard

[paul hardy]

as defined in the IPC notice the water pipe is the only system that refers to water the other systems (sanitary,soil and waste as defined in a plumbing system) refer to waste only and a sanitary system even excludes "rainwater"

WATER PIPE
Riser. A water supply pipe that extends one full story or more to convey water to branches or to a group of fixtures.
Water distribution pipe. A pipe within the structure or on the premises that conveys water from the water service pipe, or from the meter when the meter is at the structure, to the points of utilization.
Water service pipe. The pipe from the water main or other source of potable water supply, or from the meter when the meter is at the public right of way, to the water distribution system of the building served.

SOIL PIPE. A pipe that conveys sewage containing fecal matter to the building drain or building sewer.

WASTE PIPE. A pipe that conveys only waste.

DRAINAGE SYSTEM. Piping within a public or private premise that conveys sewage, rainwater or other liquid wastes to a point of disposal. A drainage system does not include the mains of a public sewer system or a private or public sewage treatment or disposal plant.


Building gravity. A drainage system that drains by gravity into the building sewer.
Sanitary. A drainage system that carries sewage and excludes storm, surface and ground water.
Storm. A drainage system that carries rainwater, surface water, subsurface water and similar liquid wastes.




A DWV system in no way is a water system period.

[paul hardy]

AD
better read this from the IRC

R201.3 Terms defined in other codes.

Where terms are not defined in this code such terms shall have meanings ascribed to them as in other code publications of the International Code Council.

and I am agreeing with HG that DWV is concidered "other metallic piping" just not with jerry that it is water piping and yes it is a plumbing system as you have posted just not a water system.

[H.G. Watson, Sr.]

Thanks Paul Hardy for the IPC definitions (which apply).

Seems some IRC users don't know diddly about the code they're using :D.

Regarding the erroneous info from Mr. Peck addressing questions about metal water pipe systems (which are all "wet" - meaning wrong):The NEC for which the electrical chapters of the IRC are based, long ago gave up on tring to enforce electrical code requirements upon the Plumbing trades.

There has been no NEC requirement for metalic water pipe to be part of a system, or that it be electrically continuous for a LONG time (five code cycles or more, probably more like 25 or more years ago).

IIRC that (electrically continuous (continuity) and bonding requirements for metalic water pipe and gas pipe) showed up about circa '71. Dropped off somewhere between the early 80s code cycles and several cycles prior to '96. About the same time, but actually IIRC two or three code cycles later - so did the exception/permission to "float a ground" from a receptacle to metalic water pipe {'93 - 250.50(b)} .

Back in 71 one was required to bond the gas pipe to the metalic water pipe - and make the whole works electrically continuous (continuity) imagine that.

Now to the assertions of Mr. Peck that should there be a section of non-metalic pipe in the otherwise metalic water distribution system it MUST be bonded/jumpered over - he is likewise is all wet (wrong): that is NOT the case - (we're not talking about the first few feet and jumping over water meters, filters, etc. for the first few feet of pipe entering structure when same is being used as a GEC "made" electrode, we're talking about after those first few feet). That would only be required IF there were post 71 and pre (about 93) "floating grounds" or EGCs not otherwise corrected. (And most HIs would be citing such "floating grounds" as something deficient and needing to be corrected for safety).

CMP-5 ROPs have addressed the matter quite consistantly for the last few code cycles - a metal water piping system is a complete system - completely metalic and electically continuous from start to finish. When there is anything between any part of it, non-metalic un-bonded/jumpered, it is NO LONGER COMPLETE, and THEREFORE NO LONGER A METAL WATER PIPE SYSTEM, and according to CMP-5 if not bonded (no requirement to do so over the break) then the remaining metal water pipe(S) are a sub-paragraph (B) situation {250.104(b)} PERIOD.

Mr. Peck is confusing two distinctly different AREAS of the CODE - and cross applying his confused understanding of one section upon another {250.53(D)(1) vs. 250.104 and Table 250.66} - incorrectly (and disregarding NFPA Style Guide).

E-forcing Peckisms is not how the NEC is written or to be used.

There is no need for me to cite myrad of CMP-5 published reports.

For those that care to read further, Watch for (among other well discussed posts and) citations from CMP-5 (apologies in advance if recommending particular topic threads in another forum is a faux pas):

gas hot water heater jump or not - Mike Holt's Forum (http://forums.mikeholt.com/showthread.php?t=82314)

Bonding the copper plumbing in a dwelling.? - Mike Holt's Forum (http://forums.mikeholt.com/showthread.php?t=117699)

Warning, the two above are LONG topic threads, which start off slow, especially the 2nd one (a few pages of not much to say) but they do eventually and quite completely cover the subject with many citations from the code making panel which writes this part of the code (NEC) and make a good read on a rainy day, IF one is interested in the topic and can follow along (not easy if you average a new refreshing beverage every third page :D).

The NEC never allowed to "float a ground" to DWV or building drain or building sewer, nor use same for a GEC in the 70s or early 80s. There was no requirement to make either electrically continuous (bond over or maintain continuity) when in 71 the "idea" of the NEC mandating same to complete metal water piping system(s) was introduced.

P.S. prior to 1996 NEC was common to the neutral as an equipment ground.

[Alexei Chaviano]

Hi good boys,all of you put me to think about this, and every one bring up realy good points.I'm a baby on this compare with you but the way I see NEC 250.104(B), "I'm may be wrom",it's look like pipes entering in a equipament or close to any king of power outlet,that can energize the metal pipe in cuestion;becouse even it will be bonded sizing the jumper by 250.122 table "using the rating of the circuit that is likely to energize the piping system".But any way the porpouse of code is for safety,is not so? Based on this if some one,for safety matters,want to bond every metal pipes in a building good.I wish every bady how tush an electrical system think more in what is safety then all a technicality the people use to look for.

[Jerry Peck]

I have a question, how does one propose to bond cast iron DWV pipe w/ No-Hub bands?


Rollie,

My post, and thought, was on the OLD cast iron systems which were cast iron hub and spigot with oakum and lead filled joints.

The modern cast iron systems, with hubless fittings, like the Fernco and others, would effectively make that no a metallic system as each pipe length and each fitting would be isolated from the adjacent pipe length and fitting.

In the high rises I have inspected with cast iron DWV and hubless fittings, yeah, there was not even a thought of bonding the DWV and they were not even considered a metallic "system", so bonding to them never came up. It would be like installing copper piping with CPVC fittings and adapters between every piece of copper - there is no "metal system", just discontinuous sections of copper.

The main key wording is "metal water piping system", of which the above would not meet as the "metal" was not a "system".

If one thinks the reason for bonding is that there is water in the piping, then one would have to bond a CPVC or PEX piping system too, and everyone knows there is no reason to do that.

[H.G. Watson, Sr.]

Rollie,

My post, and thought, was on the OLD cast iron systems which were cast iron hub and spigot with oakum and lead filled joints.

The modern cast iron systems, with hubless fittings, like the Fernco and others, would effectively make that no a metallic system as each pipe length and each fitting would be isolated from the adjacent pipe length and fitting.

In the high rises I have inspected with cast iron DWV and hubless fittings, yeah, there was not even a thought of bonding the DWV and they were not even considered a metallic "system", so bonding to them never came up. It would be like installing copper piping with CPVC fittings and adapters between every piece of copper - there is no "metal system", just discontinuous sections of copper.

The main key wording is "metal water piping system", of which the above would not meet as the "metal" was not a "system".

If one thinks the reason for bonding is that there is water in the piping, then one would have to bond a CPVC or PEX piping system too, and everyone knows there is no reason to do that.

Still spoken and back peddling like a man without a clue.

WRONG.

The reason for the TWO DIFFERENT PROVISIONS is sub paragraph A is for what (IF A CONTINUOUS SYSTEM) may be continuous (continuity) to the MADE electrode GEC and the five feet within (zero sys. ref) - WATER LINE and what MAY NOT BE.

DWV has NEVER been sub paragraph A..

[Jerry Peck]

Still spoken and back peddling like a man without a clue.

WRONG.

The reason for the TWO DIFFERENT PROVISIONS is sub paragraph A is for what (IF A CONTINUOUS SYSTEM) may be continuous (continuity) to the MADE electrode GEC and the five feet within (zero sys. ref) - WATER LINE and what MAY NOT BE.

Yep, you are still speaking like a man without a clue - were are talking about BONDING ... NOT ... GROUNDING and the above is referencing GROUNDING items, i.e., "may be continuous (continuity) to the MADE electrode GEC and the five feet within" ... that is GROUNDING path, not bonding path.

I pulled out a random older NEC to get back past the newer wording being used to tweak the NEC wording and the one I pulled out was the 1975 NEC, which states the following:
- 250.80. Bonding of piping systems. All interior metal water and gas piping that may become energized shall be bonded together and made electrically continuous. An equipment bonding jumper sized in accordance with Table 250-95 shall be connected between the bonded piping system(s) and the grounding electrode conductor at the service disconnecting means.
- - Bonding to sewer piping and metal air ducts within the premises will provide additional safety.

The last part is equivalent to what are now known as FPN.

Does that "mean" that bonding of the METAL DWV system was 'not required'? It does imply that may have been the intent, but it also acknowledges that bonding to the METAL DWV system HAS BEEN DISCUSSED AND CONSIDERED by the code making panels.

H. G. needs to get down off his high horse (that hobby horse he climbs on) and read, and understand, what is being discussed ... BONDING ... not ... GROUNDING. And then understand that metal DWV being bonded is not a far fetched or random thought, that the people he professes to know so well discussed and considered it for quite some time.

Without going back through my old codes to see the progression of the wording, it can definitely be stated that the bonding of metal DWV is certainly not a strange notion to the code making panels.

[H.G. Watson, Sr.]

Yep, you are still speaking like a man without a clue - were are talking about BONDING ... NOT ... GROUNDING and the above is referencing GROUNDING items, i.e., "may be continuous (continuity) to the MADE electrode GEC and the five feet within" ... that is GROUNDING path, not bonding path.

I pulled out a random older NEC to get back past the newer wording being used to tweak the NEC wording and the one I pulled out was the 1975 NEC, which states the following:
- 250.80. Bonding of piping systems. All interior metal water and gas piping that may become energized shall be bonded together and made electrically continuous. An equipment bonding jumper sized in accordance with Table 250-95 shall be connected between the bonded piping system(s) and the grounding electrode conductor at the service disconnecting means.
- - Bonding to sewer piping and metal air ducts within the premises will provide additional safety.

The last part is equivalent to what are now known as FPN.

Does that "mean" that bonding of the METAL DWV system was 'not required'? It does imply that may have been the intent, but it also acknowledges that bonding to the METAL DWV system HAS BEEN DISCUSSED AND CONSIDERED by the code making panels.

H. G. needs to get down off his high horse (that hobby horse he climbs on) and read, and understand, what is being discussed ... BONDING ... not ... GROUNDING. And then understand that metal DWV being bonded is not a far fetched or random thought, that the people he professes to know so well discussed and considered it for quite some time.

Without going back through my old codes to see the progression of the wording, it can definitely be stated that the bonding of metal DWV is certainly not a strange notion to the code making panels.

Your diatribes and erroneous conclusions are not supported by CMP-5, as the code was written then or now.

Peck is wrong (repeatedly on this thread). CMP-5 is correct, including as to what a "system" is and is not, and what is and is not an "interior metal water piping system", what constitutes a "system", and what is simply "interior metal pipe". Similarly CMP-5 has discussed "that may become energized" vs. "likely to"
.
By the 1984 code cycle the words, "that may become energized" changed to "which may become energized" and "and made electrically continuous" were removed from 250-80 and bonding the water piping to gas piping is not mandated, and has not been in any code cycle from that date. The section was moved to 250.104 in the 1999 cycle. "that is likely to become energized".