Electrical Discontinuity

Discussion in 'General Electronics Chat' started by David Pierce, Mar 27, 2015.

  1. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    I am a general contractor and within the governing documents of my project there is a general note indicating ED.
    4. Electrical discontinuity between the carrier pipe and the casing or tunnel liner shall be verified at intervals no less than (1) test per joint of pipe. Contractor shall document each test.
    A. How is this test performed
    B. If there isn't ED how would you discharge the continuity
    C. Is there a document to record this test

    Note:
    The casing is steel welded every 20' and the carrier pipe is C900 with carrier spacers by Recon ( rubber against the C900 and plastic legs to hold the C900 in the center of the casing ). Also this casing will be pressure grouted.
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    First guess based on the little information provided would be
    ASTM D5162
     
  3. BR-549

    Well-Known Member

    Sep 22, 2013
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    It depends on where you are. Location, location, location.
     
  4. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    I quoted right out of the documents. I have made a 100' bore with steel pipe welding the joints every 20' and this bore is 18' deep. I then installed the spacers mentioned and pushed the c900 into the casing.
    The inspector is asking for the ED test now. If you believe ASTM 5162 covers this I will review the standard.
    This project is located in Dallas Texas
     
  5. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    Dallas Texas
     
  6. alfacliff

    Well-Known Member

    Dec 13, 2013
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    "how would you discharge the continuity"? what are you refering to?
     
  7. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    I am not sure that is why I am asking. Ground rod attached to the steel casing?
     
  8. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the test is just useing an ohmmeter to check for shorts between the casing and center. there should be no conduction (infinite resistance).
     
  9. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    This is what I thought, but would I touch the casing and the C900. In the final configuration you have the casing, the plastic spacer, rubber between the spacer and the C900 then the C900 ( water main )
     
  10. BR-549

    Well-Known Member

    Sep 22, 2013
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    It means the inner sleeve has to be electrically insulated. Verified in each section.

    Your local electrician will know the proper procedure in your area.

    Have him preform and doc for you.

    Have one of your electricians with him to learn.

    In the future....it is best to do this while constructing.

    It is an easy procedure, but that does not matter.

    The bureaucrats don't care so much about the results of test.

    They care about your procedure.

    Let someone else do the first one.
     
  11. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    Yes, I believe what you are saying is correct, but I have verified with 2 master electricians, one engineer and 1 lab before I posted. They are stumped when it comes to the actual test.
    A. Push 20' of C900 into the casing attach the meter?
    B. If the C900 is charged how do or do you discharge?
    C. Push 20' of C900 into the casing then attach the meter to the casing?
     
  12. BR-549

    Well-Known Member

    Sep 22, 2013
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    Very simple......ask the permit inspector what he wants. The inspector is the one you must satisfy.

    There is no charging or discharging. You will be checking continuity with an ohm meter.

    I don't know your construction procedure.

    I am not familiar with your components.

    Start with first section. So let's say you start with inner pipe first. Install inner pipe, install outer pipe. Check continuity. It should be open.

    If not....find and eliminate connection. Measure again, verify and record.

    Install next section and measure.

    It's better to check each section.....so that when your done....it you have continuity......you don’t have to dig up the whole pipe line to find it.
     
  13. alfacliff

    Well-Known Member

    Dec 13, 2013
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    the test should be probably done with a "meggar" a high resistance ohmmeter. any charge on the pipe would be from static electricity. touch a wire from one pipe to the other to discharge.
     
    BR-549 likes this.
  14. BR-549

    Well-Known Member

    Sep 22, 2013
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    alfacliff might be right if the permitter is concerned with the insulation. Ask first.

    It's always best to check with regulating engineers before work begins. Then everyone is on the same page.
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I would also say high voltage insulation megger. Not the ground resistance version.
    Max.
     
  16. BR-549

    Well-Known Member

    Sep 22, 2013
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    What are you pumping?
     
  17. David Pierce

    Thread Starter New Member

    Mar 26, 2015
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    Thank you to all the folks that helped me out. The City has agreed that the test isn't required when the casing is metal and the carrier pipe is poly. If anyone comes across this application again steal on steal is where the tests will need to be taken.

    Again thank you.
     
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