Gas water heater ground

Discussion in 'Electrical Forum discussion & Blog' started by hids2000, Dec 15, 2009.

  1. hids2000

    hids2000 New Member

    Messages:
    63
    Location:
    Belleville NJ
    I am redoing my kitchen and thought it would be easier to replace the copper lines with PEX so it can go snake down the basement water heater easier.

    1) I have a gas water heater, why is there a ground wire between the cold and hot copper pipes about 12" above the water heater? Isn't the heater it self metal? And it is sitting on the ground already so what is the reason for the short ground wire between the pipes for grounding?

    2) If I do replace the kitchen cold and hot pipes with PEX tubing and connect them to the top of the current water heater what else needs to be done to meet code? I assume now the kitchen faucets are no longer grounded. If this will cause me more problem than I will run it with copper pipe instead of PEX.

    thank you.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,835
    Location:
    Cave Creek, Arizona
    heater

    I install the "jumper" between the hot and cold lines BECAUSE the heater is metal if water heaters in a particular house seem to fail too frequently. It is my belief, valid or not, that when water heaters fail within a few years of installation, especially if it happens to more than one, that there are residual currents leaking into the hot water piping. As these currents, and they are not detectible by common means, gravitate to the cold water pipe and then to the earth, they eat away at the stell water heater shell. The jumper lets the currents bypass the heater. This may or may not increase the life of the water heater, but I had one house where one heater failed. I installed a new one, and in a matter of months it also failed. The top of the water heater looked like someone had taken a can opener to it from the hot pipe to the cold one. I installed the new heater AND a jumper, and it has lasted at least 8 years now.
  3. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Because someone don't understand just what is meant by bonding as outlined in 250.104 of the NEC
    There is no requirement to be found anywhere in NEC for the past 25 years for this stupid installation.
    This bond serves no practical purpose.
    This bond is a waste of time and material
    This bond is due to the lack of education
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    In the state of North Carolina you would be fined for this practice as a plumber is not allowed to make electrical installations.
    Understanding a parallel circuit would let you see that the jumper does nothing to prevent current from flowing from the hot to cold through the tank should current be applied to the water pipe.
    The train of thought that current somehow leaks out the ground is completely unfounded and forbidden by the laws of physics.
    The laws that govern current flow state that every electron that leaves the transformer and entering the house must return to the transformer so no electron can leak out anywhere especially to earth.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,153
    Location:
    New England
    As I understand it, if you want to use pex, you will need (I think) at least 18" of copper at the top of the WH before you transition to pex. This is to protect the pex from overheating caused by the flue.
  6. hids2000

    hids2000 New Member

    Messages:
    63
    Location:
    Belleville NJ
    So if I leave at least say 2ft of copper on the hot side of the water heater than to PEX tubing I will have no problem with any electrical codes for the kitchen sink and faucets not grounded?
  7. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    Electrical things can malfunction. A stray wire can touch something metal.

    Like a stray stranded wire inside a range can touch the metal cabinet.

    Or heat can melt the insulation off of a wire and the wire can touch something metal like a water pipe or a gas pipe or a metal heating vent.

    And things like water heaters have plastic pipes inside and use rubber grommets which electrically isolate the cold water pipe from the hot water pipe. Also some water meters can electrically isolate the house side from the street side due to rubber grommets being used. So might see a ground jumper across the water meter too.

    With that said, it is a good idea to electrically "bond" to ground metal things like pipes, metal vent systems, metal cases of appliances, etc.

    Then should a "hot" electric wire accidentally touch the metal object, this will cause a short to ground and the breaker will trip. Or it will keep the metal object at "ground potential" and not be a danger to anyone touching the metal object.

    And the danger is with something like a plumbing system with pipes running all over the place. Lots of opportunity for something electric to malfunction and energize ALL the metal pipes!

    BUT if you are installing plastic pipe to the hot and cold side of the kitchen faucet, then this would electrically isolate the faucet from the other pipe system - So not to worry!

    The faucet itself does not have any electrical components, so no risk of an electric wire touching that faucet (and someone touching the faucet and being shocked).

    So basically a common sense sort of thing - added safety in case something should malfunction.

    Note: I read somewhere that common sense was not so common! :)

    P.S. Be sure when replacing metal water pipe with plastic pipe that you are not disrupting your main electrical system ground. These used to be only connected to a cold water pipe ground. These days a ground rod or two is required. Ask your local electrical inspector or an electrician.

    VERY important to have a good main electrical system ground!
  8. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    If there is 10 feet of metal water pipe in contact with earth then the grounding electrode conductor must be connected within the first five feet where it enters the building see 250.52 (A)(1)

    If there is a “complete†metal water piping system on the interior of the building then a bonding jumper must be installed at any accessible point on the metal water pipe see 250.104(A)

    If the metal water piping system is not a complete metal water piping system then the equipment grounding conductor installed with the branch circuit that is likely to energize the pipe can do the bonding see 250.104(B)

    Nowhere in the NEC does it require the hot and cold pipes to be bonded together nor any metal duck work or any other metal that is not an appliance that has electricity ran to it.
  9. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    Turn on a lot of stuff in your house and measure the current in this wire. If it's not zero it must be doing something.:confused:
  10. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    250.104 (A) - "Metal water piping system"

    What does that mean? Cold only?
  11. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    The following are the kind of things which can happen. Could these accidents have been prevented?

    "metal duct and vent tested positive for 110 volts"...
    http://www.clickorlando.com/money/7302637/detail.html

    "The wiring had to be in the exact position, the duct work installed - installed completely to code - but over time they were close enough together to rub and it rubbed in the exact spot on the wiring to reach the hot wire"...
    http://www.montanasnewsstation.com/global/story.asp?s=10647951&ClientType=Printable

    "This year an appliance installer died from electrocution due to an energized metal framing member that came in contact with the metal duct that was connected to the appliance"...
    http://74.125.155.132/search?q=cach...cuted metal ductwork&cd=9&hl=en&ct=clnk&gl=us

    "hidden power lines and metal duct-work are a constant risk for worker's electrocution"...
    http://www.air-techinternational.com/homeprep.html
  12. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    The water piping SYSTEM needs to be BONDED. When used as a grounding electrode and connected within 5' of the entrance, only the cold water side is bonded. Many water heaters have dielectric connectors or bushings that do not connect the hot to the cold. If you have a shower, the mixing valve is all you need to connect the hot side with the cold side. If you don't have an all metal mixing valve then the bonding jumper between the hot and the cold is required and is to be size accordingly. This is not to be confused with the bonding that is required when you have an appliance connected to the electrical system and gas.

    When you see the jumper, it may or may not be needed but in some cases it is. If you have a pex or plastic supply system and only small areas of copper that are isolated to the components they serve then they will not be required to be bonded.
  13. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,835
    Location:
    Cave Creek, Arizona
    jumper

    The heater is a "high resistance" circuit, (because it has to use the water to complete the circuit since the dielectric devices are preventing a direct metal to metal path), and the jumper is a low resistance one, therefore, the current is going to seek the easier path. You mean that a plumber cannot change an electric water heater in your state unless he has an electrician disconnect it, then come back and reconnect it after the installation? Your heaters must be enormously expensive to change. I hope you do not have "gas fitters" who are the only ones permitted to work on gas piping, or the gas heaters would be the same way. There have been times when I have done almost as much electrical work, even trouble shooting circuits for electricians, as plumbing.
  14. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Yes! The equipment grounding conductor for the air handler would have carried the fault current back if the installation had been installed correctly.
    I didn’t read the article and don’t plan to read the article but anyone with any common sense would know if the duck work rubbed a bare spot in a nonmetallic cable then both the cable and the duck was installed incorrectly. Why was the duck work moving around in such a fashion that it would damage the cable? Could it have been installed in a fashion that would allow movement?
    Why was the nonmetallic cable installed in contact with the duck?
    Either or both of these could have been installed incorrectly which would have caused the duck to become energized.

    Can you provide a code reference that requires this type of silly installation? Before you answer look closely at the plumbing codes and see just how many different piping systems that are allowed to be installed in a dwelling unit. See if the plumbing code calls out a difference between hot and cold potable water.

    This is a false statement as current will take every possible path available to it.
    If current always took the path of least resistance how can a human ever feel electrical shock? Wouldn’t the current choose to travel on a path of lesser resistance?

    Yes unless the plumber has an electrical license then they are required to hire an electrician to disconnect and reconnect the electrical circuit.

    Plumbers can also install gas lines if their license covers gas piping. If not then they must enlist the aid of a licensed HVAC installer.
  15. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    It means the potable water and the bonding conductor is to hit at any point on either the hot or cold water pipe at any point that is accessible

    (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 shall be accessible.
  16. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    I'll go with what the inspector said above! :)
  17. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Which inspector the NEC inspector or the home inspector.
    What I have done is quoted the NEC which is what all installers and inspectors MUST follow not a bunch of jibberish from those who don't understand current flow or even grounding for that matter.

    You have the choice to go with whom ever you choose but just because you go with some post does not make you or them right now does it?

    Personally I perfer to go with the word as it is printed in the Code as it is the only correct way to go.
  18. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    250.104A

    We have enforced that for years. There is often NO continuity between the cold and hot water pipes therefore the system is not bonded if there is no continuity.

    For years this has been enforced by others and myself. It is simply common sense. If there is no continuity between the hot and cold piping due to the type of water heater installed, especially with a lack of a mixing valve then in order to bond the metal water piping system, you must provide a jumper between the hot and the cold.

    I think you will find yourself out in left field on this one. Having been an inspector for years, and IAEI and NFPA member and having access to panel members who are responsible for changes in the code, I have been able to verify the intent of issues like this.

    Some times you just have to admit that you are wrong and eat a piece of humble pie. I am not always correct and I learn something new every single day. The more that I learn, the more I realize just how much I don't know. This issue was resolved years ago and is something that all of us are fully aware of.


    Now you are aware of it and can learn from it. Eat the humble pie. I have already and will eat more soon. Just not on this issue.
  19. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,540
    Location:
    North Carolina
    Having been an inspector and electrical inspector instructor certified by the state of NC for years a and having been directly involved with the members of the IAEI and being the coauthor of the Instructor’s Manual for Electrical Inspectors for the state of North Carolina I don’t think that I have to admit anything because there is no requirement to make a metal water electrically continuous and hasn’t been since the 1984 edition of the NEC.

    Just because you and your comrades in arms has been enforcing something means nothing more than you and your comrades in arms are not enforcing the letter of the NEC. Once again I ask you for clear statements quoted from the NEC that requires me to bond the potable water system twice or to make it electrically continuous. I am not asking you for what you think is common sense but clear verbiage from the NEC that requires this silly installation.

    5-235 Log #1834 NEC-P05 Final Action: Reject
    (250.104(A)(1))
    ____________________________________________________________
    Submitter: Mark T. Rochon, Mark J. Rochon Master Electrician
    Recommendation: Revise as follows:
    General Combination metal water piping system(s) separated by nonmetallic water piping system(s) where may become energized 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 the one or more grounding electrodes used.
    Substantiation: Nonmetallic water piping systems are being inserted between our metal water piping system and today’s code is not recognizing these changes.
    Panel Meeting Action: Reject
    Panel Statement: The conditions indicated in the substantiation are already covered by 250.104(B) where there is not a complete metallic water piping system
    Number Eligible to Vote: 15
    Ballot Results: Affirmative: 15
    ____________________________________________________________
    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


    As can be seen in these two proposals Code Making Panel 5 makes the statement very clear that continuity of a metal water pipe is not important.
    I personally know several members of CMP 5 and have broke bread with them on many occasions. I have worked side by side with a couple of these real smart men.

    Tomorrow I will spend all day fulfilling some of the responsibility I have being a member of second committee down on this page. :)
    Pay close attention to some of the names on this education committee.


    You can keep enforcing something that was removed from the codes 25 years ago if you like and the people in your area allows you to do so :(
    but here in the great state of North Carolina we have a real good education program where we insure that our inspectors only enforce the code as it is written and not what they think makes common sense. :)

    Edited to add:

    Here is where all this bull crap of bonding the hot and cold came from. In this code cycle the green screw of a receptacle could be attached to a metal water pipe to ensure there was a fault path back to the source in order to operate the overcurrent device.
    The CMP realized that the plumbing codes would allow a nonmetallic repair to the metal water pipes so this requirement was removed from the electrical code.

    [​IMG]

    I am still awaiting your post showing where todays code requires the potable water to be electrically continuous.
    Last edited: Dec 18, 2009
  20. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    Gas water heater with dielectric fittings will not conduct. It is not connected to electricity at all. When we checked these for continuity, there was none.

    In the absence of line voltage and grounding, 250.104B cannot apply, therefore, common sense and a responsibility to the public applies to ensure that the other 200 feet if copper piping in the home is bonded as required under 250.104A.

    Most homes have a shower so the mixing valve suffices as the bond between hot and cold of the "system", therefore we rarely have the need to require this under 250.104A.

    I and others prefer to protect the public by ensuring there is a bond to all metal water piping in the home and do what is right vs trying to use & interpret the code to such a technical point that the meaning of the code for the safety and protection of the public is lost. Sometimes common sense goes a long way.

    I know a few people like you that are so literal, you misinterpret the actual meaning and intent of the code.

    Protect the public, ensure that the metallic water piping IS bonded as it makes up at least half of the piping in the house. There are instances where it is NOT bonded and we have proven that with DMM's, Meggers & my trusty Simpson analog.

    So the rest of us that care about the public will still require this in the rare occasion that continuity between hot and cold does not exist on an all metallic water piping system and quality electricians will continue to install the jumper for the $10 cost.

    Of course in your world, the $10 is not justified and neither is bonding the other 50% of the metallic water piping because you simply do not understand that there are times where there is not continuity. Probably don't know what a dielectric union is anyway.

    I have told many electricians that the bonding jumper was not required because the shower mixing valve already served that purpose. You need to understand all of the pieces of the puzzle.
    Last edited: Dec 16, 2009
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