Gas water heater bonding

Discussion in 'Electrical Forum discussion & Blog' started by ankhseeker, Jan 8, 2014.

  1. jwelectric

    jwelectric Electrical Contractor/Instructor

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    [
    What is happening when you read 250.104(A)(1) is you are reading into it what you want it to say instead of reading it for what it says. 250.104(A)(1) is addressing metal water pipes only.

    “Expansion fittings and telescoping sections of metal raceways†how does this apply to metal water pipes. If we are going to discuss metal water pipes let’s please stay on subject and not try to inject conduit into the picture
  2. bluebinky

    bluebinky Member

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    HJ, thanks for the carefully though through replies. It would be interesting if you were my local inspector.

    I do like the interpretation of "likely to become energized". I haven't had the guts to try that one in CA.

    Anyway, while I don't agree with HJ 100%, I really appreciate the opportunity to learn and be challenged. I just wish I had time to properly try to "win" this debate, but I really need to get back to my day job.
  3. DonL

    DonL Jack of all trades Master of one

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    Did You get your wires crossed ?


    Maybe so.
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

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    The laws of physics that govern current flow clearly state that current flows from its source back to its source. In other words any current on the metal water pipe would have to originate from a source and return to that source.

    Current does not somehow appear and disappear to earth. A bonding conductor from hot to cold does nothing to help protect a water heater from corrosion.

    There is no Win to a debate that is based on tradition verses the adopted codes or electric theory. The facts stand as they are. I have only presented the facts and have used the adopted codes to do so and all anyone else has done in this thread is post speculation and tradition.
  5. bluebinky

    bluebinky Member

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    393
    Location:
    Santa Clara, CA
    Maybe, but not really.

    JW seems against bonding hot and cold metal pipes at a water heater, yet at least two places in CA mandate it. If I really wanted to change JW's mind (or be convinced otherwise), I'd probably have to take time off from work -- tempting for the educational value, but...

    For galvanic issues, that would be an even bigger battle.

    A long time ago, bonding hot and cold made the AM radio station on our phone go away :p
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

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    [
    I am not against anything that is per the NEC and it is the NEC that mandates the installation of bonding conductors. Nowhere in this state is this silly method used. We are smart enough to know that any shower mixing valve is going to get that job done should it even need doing.

    You can rest assured that I am showing the text of the NEC but am hearing nothing but tradition and ole wives tales. Yes there is time involved in any education and I have spent many many hours getting mine and will be spending many more hours in the years to come.

    This issue will only take a few minutes of reading. Three things must be present in order to have galvanic corrosion occur, two dissimilar metals and DC current. Should the proper electrolyte be used then the DC current can occur between the two metals.

    When discussing galvanic corrosion in water heaters the issue of the two dissimilar metals, the copper piping and the zinc used in the pipes and tank of a water heater we must know that the current between the copper and the other pipes is what causes this reaction. To bond the copper pipes is doing nothing more than giving more area to the copper and is doing nothing to stop the current between the copper and the zinc in the other pipes as it is the two that is the cathode and anode of the current flow.

    Stick a zinc nail and a copper nail into a potato and connect a single cell light bulb to the nails. This same thing is what is happening between the water heater and the copper pipes. Putting the two in electrical contact by the use of brass unions and the problem is gone but bonding the copper together does nothing to solve galvanic corrosion.

    These are two completely different electrical systems. Although I will not argue that the coincidental occurrence did not happen you can rest assured that the bonding of the two pipes had nothing to do with it.
    I remember one time long ago when I turned on the kitchen light our security light went out. Don’t want that happening so we use candles and kerosene lights in the kitchen now days.
  7. houptee

    houptee Member

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    A neighbor of mine who has worked for his family electrical business for many years once told me using No-Al-Ox compound was not required or mentioned anywhere in the NEC code but everyone just keeps using it and the inspectors look to see it was applied. He said the new aluminum wire is much better than the old stuff and does not need it. Anyone know if that is true or is it also a tradition thing?
  8. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Your neighbor is correct. In the NEC the use of the junk has restrictions as outlined here.
    110.14 Electrical Connections. Because of different characteristics of dissimilar metals, devices such as pressure terminal or pressure splicing connectors and soldering lugs shall be identified for the material of the conductor and shall be properly installed and used. Conductors of dissimilar metals shall not be intermixed in a terminal or splicing connector where physical contact occurs between dissimilar conductors (such as copper and aluminum, copper and copper-clad aluminum, or aluminum and copper-clad aluminum), unless the device is identified for the purpose and conditions of use. Materials such as solder, fluxes, inhibitors, and compounds, where employed, shall be suitable for the use and shall be of a type that will not adversely affect the conductors, installation, or equipment.

    There is also 110.3(B) which states that if it is used it must be applied according to any instructions,
    (B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.
    If someone wants to take the time to read the instructions when applying this junk one will see that each strand of the conductor has to be brushed and the compound applied to all expose conductor not just dabbed into the terminal. As an inspector when I see it if it has not been properly applied it cost the installer one more inspection fee.
    If the terminal does not require the junk then the installer has the duty of removing the junk from the terminal.
  9. bluebinky

    bluebinky Member

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    Location:
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    AHA, we did "get our wires crossed". NEC with a few mods applies out here... so we are actually in agreement, sort of.

    I think that's a little harsh. NEC requires hot to cold bonding, but where does it say it has to be at the water heater?

    True, and obvious in your case. Choosing one's battles doesn't imply laziness, though.

    Oversimplification, but essentially correct. What about a thermocouple or solar cell? -- nothing but dissimilar metals.

    No, this was real and repeatable. Just a some bad wiring and dissimilar metals...


    Houptee, as for the No-Al-Ox or whatever, that is not what I meant by "tradition". There was a thread here a while back that quickly changed my mind against the stuff, though.
  10. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Where does the NEC make a requirement to bond hot to cold?
  11. Stuff

    Stuff Member

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    Location:
    Pennsylvania
    How does a piece of copper attached to the hot and cold pipes violate 250.104(A)(1)? The rule concerns bonding the water system to the GEC. Yes, this wire should not be called a system bonding jumper. It is intended for the continuity of the water pipe system which is not required as you pointed out, but it also is not prohibited.
  12. DonL

    DonL Jack of all trades Master of one

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    Good Stuff, Stuff. I have a stutter.


    I have seen the manufacture requirements in the Water Heater Service Manuals.

    Electric and gas water heaters should not be treated the same.

    Filament shorts and the like make bonding Electric heaters very important.

    With PVC in use, the electrical bonding of the whole system may not happen.

    Bonding and Grounding are two different things.

    If not done properly both can kill you.


    Are we confused yet ?
  13. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Location:
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    Let’s take your post and answer it from last to first. It will make the explanation easier. No it is not prohibited to bond as many times as you want but each bond is required to follow the guidelines of 250.104(A)(1). If one desired one could install a bond to four different places on the metal piping system as long as each one landed on either of these; 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.

    If it is ones desire to maintain electrical continuity of the metal pipe then any conductor used for this purpose is a bonding jumper as defined by Article 100 of the NEC.
    Bonding Conductor or Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected.

    So if the purpose is to have electrical continuity between the cold and hot metal water pipes then the conductor that is used for this purpose is required by Section 250.104(A)(1).

    Because in 250.104(A)(1) it mandates one of four places that a metal water piping system is allowed to bond at and another pipe is not one of them
    Or the electrode, the neutral, or the service equipment
    This is correct it is simply a bonding jumper. A system bonding jumper is defined as; Bonding Jumper, System. The connection between the grounded circuit conductor and the supply-side bonding jumper, or the equipment grounding conductor, or both, at a separately derived system.
    In most cases this will be the X0 terminal of a transformer.
  14. houptee

    houptee Member

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    Location:
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    “Article 250 is one of the most difficult and involved sections in the NEC,” said Michael Johnston, NECA executive director, standards and safety. “In particular, Section 250.4 outlines what is intended to be accomplished by grounding and bonding and the performance requirements regarding installation. The prescriptive requirements in Article 250 are much easier to understand and apply when the performance requirements are known.”


    - See more at: http://www.ecmag.com/section/codes-standards/down-earth-about-grounding#sthash.GtH9KhvK.dpuf
  15. Stuff

    Stuff Member

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    Location:
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    250.104(A)(1) is about bonding the metal water piping system to the GEC, etc. There is nothing in that section prohibiting any additional bonding, whether to the GEC or anywhere else. Is there a different section that prohibits other bonding? Essentially this would be bonding the metal water piping system to itself.
  16. jwelectric

    jwelectric Electrical Contractor/Instructor

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    250.104(A)(1) mandates the installation of bonding jumpers that are installed on metal water piping systems.
    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 (A)(1), (A)(2), or (A)(3) 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).

    In (A) it mandates that a bonding jumper be installed and that the place it lands on the metal pipe is to be accessible.
    In (1) it gives the four places that the other end of that bonding jumper has to land and another metal pipe is not outlined there.

    If a bonding jumper is installed for any reason one end must land on the pipe at an accessible location and the other end is required by this section to land either one of the four places outlined in (A)(1) but it does not mention another metal pipe anywhere now does it.

    It says that one end must land at an accessible place on the metal water pipe and the other end must land on the service panel, the neutral, the GEC if it is big enough or one of the 8 electrodes outlined in 250.52 but I can’t find where it says “or another metal water pipe”, can you.

    The use of the word “SHALL” found in both parts of 250.104(A)(1) means that this is a mandatory rule.
    90.5 Mandatory Rules, Permissive Rules, and Explanatory Material.
    (A) Mandatory Rules. Mandatory rules of this Code are those that identify actions that are specifically required or prohibited and are characterized by the use of the terms shall or shall not.
    It is not a permissive rule that allows another method.
    (B) Permissive Rules. Permissive rules of this Code are those that identify actions that are allowed but not required, are normally used to describe options or alternative methods, and are characterized by the use of the terms shall be permitted or shall not be required
    A bonding jumper installed on a metal water pipe for any reason must comply with 250.104(A)(1) and a Standard of Practice is not allowed.
  17. bluebinky

    bluebinky Member

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    Location:
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    I think the question is about whether or not "continuity jumpers" (not to be confused with bonding jumpers) can be used to maintain electrical continuity of metallic water piping, such as at a water heater.

    If I understand what JW is saying, any "jumper" on water piping is by code a "bonding jumper" and therefore must be between a pipe and a bonding point such as at the panel, etc.

    You can jumper an equipment ground such as more than one EMT going into a plastic box to maintain continuity, but not bonded pipes (according to JW's reading of the code).

    I don't see anywhere in the code that prohibits or allows "continuity jumpers" on water pipes, but the bonding part is quite clear.

    I've seen something in the plumbing code, but can't find it any more...
    Last edited: Jan 15, 2014
  18. Stuff

    Stuff Member

    Messages:
    52
    Location:
    Pennsylvania
    I am not disputing that this a mandatory rule. I am questioning the interpretation going beyond the specific actions the rule requires.

    Once the water piping system is bonded as asked for in (A) the "SHALL" is met. Nothing in this section specifically requires or prohibits additional bonds. Adding an additional bond does not undo the original bond regardless of where it connects.

    In this section no where does it say "If a bonding jumper is installed for any reason..." Is that in a different section?
  19. Stuff

    Stuff Member

    Messages:
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    Location:
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    Hmm... Interesting idea as we are reviewing the wording, not the intent. Checking definition: Bonding Conductor or Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected. Since your "continuity jumpers" are not required then they don't meet the definition of bonding jumper which helps the argument.

    Question is do they still perform the bonding function. Bonded (Bonding). Connected to establish electrical continuity and conductivity. If a system already has electrical continuity and conductivity then we are not establishing but are supplementing when adding a jumper. So a "continuity jumper" is bonding only if there is not already some other connection.

    Just trying to show that wording sometimes doesn't help. Lawyers (inspectors) interpret but judges (AHJ) validate or invalidate the interpretation.
  20. jwelectric

    jwelectric Electrical Contractor/Instructor

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    I have seen some pretty determined people in my life but I have never seen someone so determined to prove their point so hard that they start making up names for the actions they are taking. Just what is a continuity jumper?

    I do hope that we all understand the difference between an electrical raceway and a water pipe.

    I have seen installations at water heaters where the installer would bond from the water pipes to the gas pipes. When CSST is being used to supply the appliance the instructions with the CSST pipe is very clear that this is a violation. The CSST pipe will require that the gas bond be at one of the four places outlined in 250.104(A)(1).

    The codes are written and adopted for a reason. The code sections go through scrutiny for a two year period before being written. We may not understand why they are written the way they are but that is not for the installer to understand but are for the installer to comply with.

    Once the water pipe is bonded it is in compliance but any other bond is still bound by the same rule as the original bond.

    A kitchen counter top is required to be supplied by no less than two small appliance 20 amp circuits. Using the notion that once a rule has been complied with means we can do whatever we desire would be saying that once these two circuits are installed I could now install a dozen 15 amps circuit to the counter top. I don’t think any of us would argue that this would be a violation but to prove ourself right we will stoop to trying to circumvent the rules elsewhere.
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