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Thread: Current Measured on water and gas lines

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    Current Measured on water and gas lines

    I have a nagging problem about measuring electric current on metal water and gas line coming into my daughter's home. At the outset, 4-6 Amps were read on the water line. It fluctuates depending on what loads are on in the home. A toaster oven drawing 15 Amps causes an increase of 3 Amps on the water line. 2 electricians have come to inspect and not found any wiring problems in grounding system, and the power company came to measure the net current on the main service line who found 1.2 Amps flowing despite the Main CB being OFF. With main CB on, about 2 Amps was measured. The power company says there's no problem in the house, and the electricians can't find anything wrong. Discussions ensue that involves there maybe being a problem at a neighboring home.

    Does the "residual" (or possibly "objectionable" per NEC 250) current flowing despite the Main CB being OFF constitute a problem in the home OR a problem in a neighboring home cross feeding into my daughter's home?
    What amount of current measured on the water line or gas line is acceptable?
    Does this residual current flowing register on the watt-hour meter despite the Main CB being OFF?

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    It is quite possible that the current is coming through the earth from a neighbor who is on the same utility transformer. If so short of getting the utility to put your daughter on a transformer by herself, there is probably very little that can be done.

    Whether it is objectionable or not depends on your POV.
    Bob

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    Does the current flowing register on the watt hour meter? No, they measure current on the two ‘hot’ conductors, the neutral carries the imbalance of the two hots.
    Tom
    TBLO

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    Sounds like a typical neutral issue to me.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    Quote Originally Posted by petersonra View Post
    It is quite possible that the current is coming through the earth from a neighbor who is on the same utility transformer. If so short of getting the utility to put your daughter on a transformer by herself, there is probably very little that can be done.

    Whether it is objectionable or not depends on your POV.
    If a neighbor on the same transformer has a neutral problem, say a loose connection or even an open, we'd see the grounding taking up their neutral current and feeding through water and gas lines to my daughter's home neutral.
    Is there a rule of thumb about what is acceptable current readings on water and gas lines? "Some" might be expected.

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    As mentioned, the "problem" may even been from connections outside your daughter's home (neighbor on same transformer, POCO, etc).
    That said, you should not be measuring and current flow on the gas line. Her line should be electrically isolated from the neighborhood distribution system. If you are showing curent flow on the gas line I would contact the gas co. and have them check the isolation fitting (normally at the gas meter)
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    As mentioned, the "problem" may even been from connections outside your daughter's home (neighbor on same transformer, POCO, etc).
    That said, you should not be measuring and current flow on the gas line. Her line should be electrically isolated from the neighborhood distribution system. If you are showing curent flow on the gas line I would contact the gas co. and have them check the isolation fitting (normally at the gas meter)
    good point. the UG gas line should be galvanically isolated at the meter.
    Bob

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    Quote Originally Posted by Handy hank View Post
    I have a nagging problem about measuring electric current on metal water and gas line coming into my daughter's home. At the outset, 4-6 Amps were read on the water line. It fluctuates depending on what loads are on in the home. A toaster oven drawing 15 Amps causes an increase of 3 Amps on the water line. 2 electricians have come to inspect and not found any wiring problems in grounding system, and the power company came to measure the net current on the main service line who found 1.2 Amps flowing despite the Main CB being OFF. With main CB on, about 2 Amps was measured. The power company says there's no problem in the house, and the electricians can't find anything wrong. Discussions ensue that involves there maybe being a problem at a neighboring home.

    Does the "residual" (or possibly "objectionable" per NEC 250) current flowing despite the Main CB being OFF constitute a problem in the home OR a problem in a neighboring home cross feeding into my daughter's home?
    What amount of current measured on the water line or gas line is acceptable?
    Does this residual current flowing register on the watt-hour meter despite the Main CB being OFF?
    That is a very strong indication that there is a problem with the grounded conductor between the utility transformer and the main bonding jumper for your service.
    Don, Illinois
    (All code citations are 2017 unless otherwise noted)

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    Quote Originally Posted by don_resqcapt19 View Post
    That is a very strong indication that there is a problem with the grounded conductor between the utility transformer and the main bonding jumper for your service.
    I find the older I get, the dew brain cells are firing, but would that be the case since he's showing current with the main "Off".
    I would tend to think the problem might be more outside of his area with the urrent flowing back thru the pipe his neutral to the transformer.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

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    Quote Originally Posted by augie47 View Post
    I find the older I get, the dew brain cells are firing, but would that be the case since he's showing current with the main "Off".
    I would tend to think the problem might be more outside of his area with the urrent flowing back thru the pipe his neutral to the transformer.
    I agree with this line of thinking. But since he had 1.5A with the main off and 2A with the main turned on, this may indeed be a multiple location problem.

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