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Thread: Pipe bonding

  1. #1
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    Default Pipe bonding

    Does this home need a jumper cable to bond the copper pipe or does this type of meter make the grade as a continuous path?

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    Default Re: Pipe bonding

    The purpose of bonding is to keep all metallic parts at the same potential. So, yes, this meter must be bonded. 2008 NEC 250.104(3)(B).

    Last edited by Donald Farrell; 09-25-2011 at 06:30 AM. Reason: typo.

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    Default Re: Pipe bonding

    A water meter should have a jumper if, by removing the meter, you either no longer have a grounding electrode or a water pipe bonding connection. Which of the connections ends up missing will of course depend on which side of the meter the single connection is made.

    I have seen a few installations where the meter connection involves a single piece casting that is in series with the water line and continuity is maintained whether the meter is present or not. In reality, the jumper is for the safety of someone who might be removing the meter if current is flowing on the pipe due to an electrical problem, as repair work often involves installing non metallic pipe and you can't really count on the pipe being an electrode.


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    Default Re: Pipe bonding

    Quote Originally Posted by Donald Farrell
    The purpose of bonding is to keep all metallic parts at the same potential. So, yes, this meter must be bonded. 2008 NEC 250.104(3)(B).
    Don,

    In this instance, it looks to me like the pipe is at the same potential using the service ground connection. The meter can be fully removed and not effect current flow.

    Quote Originally Posted by Bill Kriegh
    A water meter should have a jumper if, by removing the meter, you either no longer have a grounding electrode or a water pipe bonding connection. Which of the connections ends up missing will of course depend on which side of the meter the single connection is made.

    I have seen a few installations where the meter connection involves a single piece casting that is in series with the water line and continuity is maintained whether the meter is present or not. In reality, the jumper is for the safety of someone who might be removing the meter if current is flowing on the pipe due to an electrical problem, as repair work often involves installing non metallic pipe and you can't really count on the pipe being an electrode.
    Bill,

    In this instance, you can fully remove the meter (see union connections) and continuity remains. In fact, the only way to remove the fitting for the meter is to cut out this fitting. If a jumper would be required across this fitting, then I would think one would be required at each and every pipe fitting? And we know that is not so.

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    Default Re: Pipe bonding

    I am probably missing something that I thought I understood. Maybe someone could clarify.

    The bonding conductor is intended to equalize all potential/voltage by connecting the metal piping to earth. Assuming the bonding conductor is directly connected to the grounding electrode, grounding terminal block or GEC, all of the household supply piping should be properly bonded (Ok, it needs a jumper at the water heater and gas supply, but you know what I was getting at). The piping before the meter should be in contact with earth, and therefore connected to ground as well.

    Is the concern the possibility of potential difference between the two points of earth contact (water main and grounding electrode)?

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    Default Re: Pipe bonding

    Ken,

    I may be myopic with regard to this topic, but I do not think so.

    The piping must be bonded together to eliminate a differance of potential between pipes and metallic components of the system.

    Surely, there can be a differance of potential with respect to the two grounds.

    Don


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    Default Re: Pipe bonding

    The fitting looked like a one piece that would maintain continuity when the meter was removed. But, given the angle of the picture I wasn't going to make the assumption.

    For those of you that are not in the electrical or plumbing business, you may not know many people have been killed in the act of removing a water meter. The reason is that electricity will take all available paths back to the source, and if the house (or a neighbor's) has a bad neutral connection somewhere in the service wiring but a good water pipe ground, the electricity will follow that ground to the next house, and indeed any other near by electrical service, with a good connection between the pipe and the neutral at the service connection point for a water pipe used as a grounding electrode. Removing the meter in this condition can put the person removing the meter in series with voltage at many AMPs. The issue isn't the fitting getting jumpered or voltage differential between different parts of the piping system, the issue is whether removing the meter breaks a connection to the grounding electrode connection on the service.

    Many people who remove meters carry a set of jumper cables to make sure there is a path for electricity when the meter is removed. Unless there is a continuous path for the metal pipe with the meter removed there should be a jumper around the meter, and SOP most places with inside meters is a water pipe bonding clamp on both sides of the meter with the grounding electrode conductor attached to both.

    Last edited by Bill Kriegh; 09-25-2011 at 03:44 PM.

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    Default Re: Pipe bonding

    Quote Originally Posted by Bill Kriegh View Post
    I have seen a few installations where the meter connection involves a single piece casting that is in series with the water line and continuity is maintained whether the meter is present or not. In reality, the jumper is for the safety of someone who might be removing the meter if current is flowing on the pipe due to an electrical problem, ...
    Quote Originally Posted by Bill Kriegh View Post
    The fitting looked like a one piece that would maintain continuity when the meter was removed.
    *
    The reason is that electricity will take all available paths back to the source, ...
    *
    Many people who remove meters carry a set of jumper cables to make sure there is a path for electricity when the meter is removed. Unless there is a continuous path for the metal pipe with the meter removed there should be a jumper around the meter, and SOP most places with inside meters is a water pipe bonding clamp on both sides of the meter with the grounding electrode conductor attached to both.
    * some parts deleted as not applicable to the following point

    The current, if any current is present, will take two parallel paths at those meters: path one will be the short way through the casting; path two will be the long way through the meter. When the meter is removed the person removing the meter is still breaking one of the paths the current is flowing on.

    Jumper cables should be used even with single castings or castings which are not completely disassembled and do not create a loss of continuity through the meter installation setup to avoid breaking one of the parallel paths for the current.

    Think of it as having two paths, one with 1 ohm resistance and one with 2 ohms resistance, you still have current flow on the 2 ohm circuit side, and if you disconnect that side you will find out just how much current was flowing on that side.

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    Default Re: Pipe bonding

    If I was in the "meter removing" business I most certainly would use jumpers - and "hot gloves". The fact the electricity takes all available paths means that there would be some current flowing across the meter even with the jumper present. With a one piece casting for the meter the chances are that the instant the meter connection is broken the easiest path will be the metallic connection of the fitting and not the person doing the disconnecting - no guarantees though. And, more than likely the situation will involve wet hands, feet, and a wet concrete floor. Not a situation for guesswork and taking chances.

    However, the jumper around a meter without a one piece fitting is mandatory most places and my first post on the subject is why and describes the situations that make it so, and is the reason the jumper is an issue. Removing the meter should never disconnect either the water pipe bonding conductor or the grounding electrode.


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    Default Re: Pipe bonding

    Quote Originally Posted by Jerry Peck
    The current, if any current is present, will take two parallel paths at those meters: path one will be the short way through the casting; path two will be the long way through the meter. When the meter is removed the person removing the meter is still breaking one of the paths the current is flowing on.

    Jumper cables should be used even with single castings or castings which are not completely disassembled and do not create a loss of continuity through the meter installation setup to avoid breaking one of the parallel paths for the current.

    Think of it as having two paths, one with 1 ohm resistance and one with 2 ohms resistance, you still have current flow on the 2 ohm circuit side, and if you disconnect that side you will find out just how much current was flowing on that side.
    OK JERRY,

    Your answer sounds pretty fishy to me.

    So let's add your jumper cable to the set up in the picture shown. The current flow will then take three paths and you will still get current flow if you take out the meter. I'm not convinced with that logic.

    There's much more resistance through a body than through a 1 inch copper pipe, and there's much more current flow (less resistance) through a one inch copper pipe than there is through a #6AWG bond jumper.

    I'm thinking that the jumper cable doesn't make it a more direct path OR have less resistance than the one inch copper pipe. Therefore - what value does it add?

    BUT - back to the original question.
    Do we "need" (code requirement) a jumper cable on this type of water meter that maintains a continuous current path when the meter is removed?

    Ken Amelin
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    Default Re: Pipe bonding

    Quote Originally Posted by Ken Amelin View Post
    Your answer sounds pretty fishy to me.
    Not fishy at all, it was just an explanation of what happens when you have parallel circuits, especially just two parallel circuits.

    So let's add your jumper cable to the set up in the picture shown. The current flow will then take three paths and you will still get current flow if you take out the meter. I'm not convinced with that logic.
    Correct, the same as Bill pointed out in the post above yours, but ...

    ... and it is an important but - the more parallel paths you have, the less current there will be in any given parallel path, so installing the jumper will reduce the current being broken by removing the meter. Installing two jumpers will reduce the current even more, installing four jumpers will reduce the current even more, and so on.

    Now, the question turns some - Which would reduce the current through the meter the most: a) a large 4/0 welding cable just long enough to jump across the meter; b) a pre-made jumper with 4 separate #8 jumpers of the same length?

    (Note: there is an answer to that, but that would involve looking up the resistance of both sizes and doing the math for parallel circuits ... so I will let someone else do the math and answer the question 'cuse I'm tired -I spent the day repairing my sprinkler system and I'm not used to doing physical work in the hot sun anymore, wears me out to easily ... ).

    There's much more resistance through a body than through a 1 inch copper pipe, and there's much more current flow (less resistance) through a one inch copper pipe than there is through a #6AWG bond jumper.

    I'm thinking that the jumper cable doesn't make it a more direct path OR have less resistance than the one inch copper pipe. Therefore - what value does it add?
    "what value does it add?"

    What value do you place on your life? That is the value it adds.

    BUT - back to the original question.
    Do we "need" (code requirement) a jumper cable on this type of water meter that maintains a continuous current path when the meter is removed?
    (bold and underlining are mine)
    - E3508.1.1.1 Installation. Continuity of the grounding path or the bonding connection to interior piping shall not rely on water meters, filtering devices and similar equipment. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in Sections E3508.1.2 through E3508.1.5. The supplemental electrode shall be bonded to the grounding electrode conductor, the grounded service entrance conductor, a nonflexible grounded service raceway or any grounded service enclosure.
    - - Where the supplemental electrode is a rod, pipe or plate electrode in accordance with Sections E3508.1.4 and E3508.1.5, that portion of the bonding jumper that is the sole connection to the supplemental grounding elect
    rode shall not be required to be larger than 6 AWG copper or 4 AWG aluminum wire.

    - 250.53 Grounding Electrode System Installation.
    - - (D) Metal Underground Water Pipe. Where used as a grounding electrode, metal underground water pipe shall meet the requirements of 250.53(D)(1) and (D)(2).
    - - - (1) Continuity. Continuity of the grounding path or the bonding connection to interior piping shall not rely on water meters or filtering devices and similar equipment.


    Water meters which are part of a manufactured setup/device where the bonding is continuous through the setup/device and the continuity through the setup/device does not rely on the water meters being in place, then, 'no', the code does not require those water meters to be bonded across.

    Now, you should also remember two things:
    - a) Bill stated:
    - - "With a one piece casting for the meter the chances are that the instant the meter connection is broken the easiest path will be the metallic connection of the fitting and not the person doing the disconnecting - no guarantees though. And, more than likely the situation will involve wet hands, feet, and a wet concrete floor. Not a situation for guesswork and taking chances."
    - b) The NEC states:
    - - "90.1 Purpose.
    - - - (B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use."


    Would you trust your life to "essentially free from hazard"?



    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Pipe bonding

    Thanks for all the replies.
    Very informative, thought provoking and as always - appreciated.

    Ken Amelin
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    Question Re: Pipe bonding

    Jerry,

    With respect to your citation, "E3508.1.1.1 Installation". Where is this citation given? Can you educate me please?


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    Default Re: Pipe bonding

    Quote Originally Posted by Donald Farrell View Post
    Jerry,

    With respect to your citation, "E3508.1.1.1 Installation". Where is this citation given? Can you educate me please?
    Donald,

    Oops ... sorry, I forgot to identify where the references came from like I usually do.

    The E3508.1.1.1 reference is from the IRC (which is from NFPA 70A), the 250.53 reference is from the NEC.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: Pipe bonding

    Why are we pulling meters?

    In the south all the water meters are buried about 6"-8" in the front yard near the street. Never are they in the house. We don't have basements so they are not in the basement. We don't have snow and the frost line is about 6 inches. Never worry about pipes freezing.

    Again, why is anyone pulling meters? The meter is just a measuring device so someone can send you bill. Are water meters failing at a high rate that they have to be pulled and replaced on a regular basis? What am I missing in this bizarre story?

    Must be some crazy northern thing with inside meters need constant pulling.

    "The Code is not a peak to reach but a foundation to build from."

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    Angry Re: Pipe bonding

    Quote Originally Posted by Bruce Ramsey View Post
    Why are we pulling meters?

    In the south all the water meters are buried about 6"-8" in the front yard near the street. Never are they in the house. We don't have basements so they are not in the basement. We don't have snow and the frost line is about 6 inches. Never worry about pipes freezing.

    Again, why is anyone pulling meters? The meter is just a measuring device so someone can send you bill. Are water meters failing at a high rate that they have to be pulled and replaced on a regular basis? What am I missing in this bizarre story?

    Must be some crazy northern thing with inside meters need constant pulling.
    Meters are pulled to be:
    1- Tested. When the customer calls to complain that the water bill is too high.
    (Okay, and sends a letter or two. Maybe has to stop by the office and yell.)
    2- Upgraded. When the company decides to put in more accurate meters, or meters that can broadcast a signal, eliminating the cost of the meter reader walking door-door.
    3- Replaced. Sometimes they just stop working.
    4- Sometimes they are disconnected to make another part of a plumbing repair or upgrade easier. Disconnecting a union is easy.

    Bruce M Audretsch

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    Default Re: Pipe bonding

    Quote Originally Posted by Bruce Ramsey View Post
    Why are we pulling meters?

    In the south all the water meters are buried about 6"-8" in the front yard near the street. Never are they in the house. We don't have basements so they are not in the basement. We don't have snow and the frost line is about 6 inches. Never worry about pipes freezing.

    Again, why is anyone pulling meters? The meter is just a measuring device so someone can send you bill. Are water meters failing at a high rate that they have to be pulled and replaced on a regular basis? What am I missing in this bizarre story?

    Must be some crazy northern thing with inside meters need constant pulling.

    I don't think there is any mass removal of meters going on. The fact is darned few are. And, if yours was replaced you might not even know about it. But, when one is removed it shouldn't be dangerous.

    FYI, there have been several cases where a person was removing a meter (for whatever reason) from a meter pit (the hole outside) and was found dead laying on the ground with arms in the pit. Electrocuted by the same process that goes on with an inside meter. The problem here is that often the requirements for the 10 feet of pipe in contact with the ground are met between the house and the meter so no jumper is required at the meter.

    Do a bit of Google searching - you'd be surprised how big an issue this is - even down south.


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    Default Re: Pipe bonding

    Also known as 'buck horns' and contrary to folklore, the current will not 'jump' threw a person when removing the meter as assumed with this meter feature.
    If this were the case... we would all be shocked to find service personnel laying beside CT cabinets after jumpers were installed while the current transformers were being removed for servicing/replacing.
    I can site more examples, but I won't. This due to the fact that as humans we won't accept any explanation of actual applied examples once we have our theoretical minds made up.


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    Default Re: Pipe bonding

    Quote Originally Posted by bob smit View Post
    theoretical minds

    No wonder, if the minds were actually physical things, they could process new information and make the associated changes.

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    Default Re: Pipe bonding

    Quote Originally Posted by bob smit View Post
    we won't accept any explanation of actual applied examples once we have our theoretical minds made up.
    That is absolutely untrue! Oh, wait...

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