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Thread: Flex gas line bond.

  1. #1
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    Flex gas line bond.

    I know gas tubing or CSST require a bond, but what about flexible appliance gas connectors or FAC?

    Are short flex gas connectors used for appliances like hot water tanks, dryers and ranges considered CSST?

    What does Nec and gas codes say on the matter?
    John,

  2. #2
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    Those short sections do not fall under the rules for CSST. Nec just states that the gas pipe needs bonding but it can be bonding with the equipment grounding conductor of the circuit that feeds the gas appliance.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
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  3. #3
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    Quote Originally Posted by Dennis Alwon View Post
    Those short sections do not fall under the rules for CSST. Nec just states that the gas pipe needs bonding but it can be bonding with the equipment grounding conductor of the circuit that feeds the gas appliance.
    Thanks Dennis. It seems a little contradictory since they'r
    e almost identical construction to CSST, but I guess they need to draw the line somewhere.

    The idea of needing a bonding conductor along the entire length of CSST tubing, only to connect to a unbonded FAC connector seems silly to me.

    Would this be considered "electrically continuous"?
    John,

  4. #4
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    Once you bond the csst then everything is bonded. If there is no csst then the black iron bonding is sufficient for the appliance flex.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  5. #5
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    Ok, thanks.
    John,

  6. #6
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    Quote Originally Posted by S'mise View Post
    The idea of needing a bonding conductor along the entire length of CSST tubing, only to connect to a unbonded FAC connector seems silly to me.
    That's not how you bond CSST. Consider that the appliance end(s) of the CSST is grounded via the EGC of the circuit(s) supplying it. A lightning strike nearby can energize the incoming gas line, creating voltage across, and thus current through the CSST, damaging it.

    By bonding the incoming gas line piping (typically black-iron pipe) anywhere from the customer's side of the meter to wherever it is nearest to the electrical system (like you would bond to water pipe), you eliminate that voltage gradient across the lengths of the CSST.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  7. #7
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    Quote Originally Posted by LarryFine View Post
    That's not how you bond CSST. Consider that the appliance end(s) of the CSST is grounded via the EGC of the circuit(s) supplying it. A lightning strike nearby can energize the incoming gas line,

    My understand is that the bonding jumper goes from one end of the csst to the other like this.Click image for larger version. 

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    So when lighting strikes the CSST will be fine but the FAC connection will blow up.
    John,

  8. #8
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    Strange, because I've always found this to be the method:

    Click image for larger version. 

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ID:	21271 Click image for larger version. 

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    Also see: https://www.google.com/url?sa=i&rct=...38195959528510
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  9. #9
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    We have always done it as Larry stated. Can you imagine what you would have to do if there were 8-10 runs if we had to run a wire along the entire length of the csst.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  10. #10
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    Quote Originally Posted by Dennis Alwon View Post
    We have always done it as Larry stated. Can you imagine what you would have to do if there were 8-10 runs if we had to run a wire along the entire length of the csst.

    Yes, there's some misinformation out there. What you two say makes sense, but I don't fully have my mind around this yet.

    In my mind, most explosions of CSST are because of lighting strikes which can cause high current to flow through the corrugated tube and blow holes in it. Adding a bond wire along it supplements it to allow more fault current to safety pass and will equalize voltage differentials.

    Assuming the gas pipe is already bonded at its source to the grounding system, what good does it do when someone adds a section of CSST to the existing black pipe to require a bond at the end of this already bonded ridged pipe? How does this protect the section of CSST?

    Perhaps I'm thinking about this wrong but when lighting strikes the ground, its path could be from the gas pipe source, or from the grounded appliance going the other way.


    Wouldn't it be better to jumper around the weakest point?
    John,

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