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Thread: Repurposing an 8/2 wire...

  1. #1
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    Repurposing an 8/2 wire...

    So my friend has an old 8/2 SER cable that used to service an A/C which has been removed. She wants to install a hot tub and wants to know if I can reuse the circuit. Would it be safe to relocate the bare wire to the neutral bar (after wrapping the bare exposed wiring with white phase tape) to supply a neutral to the spa panel? I could then drive a ground rod within 6 feet of the GFCI spa panel to supply the earth ground. Would this be considered safe? This is my first time dealing with/thinking about a situation like this... Thanks.

  2. #2
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    NO do not do that. The grounding rod will not clear the fault and the breaker will not open up.

    Why do you need a neutral for the spa?
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  3. #3
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    Quote Originally Posted by edward View Post
    NO do not do that. The grounding rod will not clear the fault and the breaker will not open up.

    Why do you need a neutral for the spa?
    I actually don't need it for the spa, I need it for the GFCI to function properly, correct?

  4. #4
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  5. #5
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    Proposed idea:

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  6. #6
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    Unless the spa is very small (2 person), 8/2 with ground will likely not be enough ampacity for the circuit. 2p GFCI discos for 240V spas need a ground, not a neutral, and most will be 50A. Spas have to be sized 125% of the circuit ampacity. The spa mfg instructions may preclude your proposed install. I'll have to look further in article 680 to see if there are more problems (code violations) here in the am.

    eta: a separate ground rod at the spa in lieu of a grounding conductor is neither safe nor code compliant. You cannot use USE/SER directly to the spa, maybe to the disco, but from there to the spa has to be an approved wiring method as described in article 680. Typically, even in SF residences, that is LFNMC or RPVC with individual conductors. You cannot run the existing cable directly to the spa; it must have a disconnect within sight of the tub that is >6' but less than 25' from the spa.
    Last edited by JFletcher; 03-29-17 at 01:26 AM.
    Electricians do it until it Hertz!

  7. #7
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    Quote Originally Posted by EEEC View Post
    I could then drive a ground rod within 6 feet of the GFCI spa panel to supply the earth ground.
    It is very important to understand why that not only doesnt work, but is dangerous. I suggest reading this sticky:


    http://forums.mikeholt.com/showthread.php?t=95495
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  8. #8
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    Quote Originally Posted by EEEC View Post
    Proposed idea:

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    NO
    do not do this.

    Assume there is fault between line 1 and the frame of the motor. Now, use yoru finger and folow the grounding wire back to the source where does the ground fault go? To the ground!!

    That will NOT break the circuit breaker, because there is no electrical connection between the ground rod and the main grounding buss.
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  9. #9
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    Quote Originally Posted by electrofelon View Post
    It is very important to understand why that not only doesnt work, but is dangerous. I suggest reading this sticky:


    http://forums.mikeholt.com/showthread.php?t=95495
    Thank you Ethan.

  10. #10
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    Quote Originally Posted by EEEC View Post
    Would this be considered safe?
    Absolutely no.

    It is dangerous.

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