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Thread: Hot Tub/Spa wire Ampacity and Breaker Size

  1. #1
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    Hot Tub/Spa wire Ampacity and Breaker Size

    Should the wire and breaker size be 100% of unit marked current or 125% ? I have seen many units just marked with a current rating, not the typical min circuit ampacity/max overcurrent rating like you would see on an air conditioner.

    Al

  2. #2
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    2005 NEC:

    680.9 Electric Pool Water Heaters
    All electric pool water heaters shall have the heating elements subdivided into loads not exceeding 48 amperes and protected at not over 60 amperes. The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices shall not be less than 125 percent of the total nameplate-rated load.

    This was the only thing I found that was spa-related that mentioned 125%. This section is in Part I of the article, and Part I applies to spas.

    [ December 30, 2005, 11:33 AM: Message edited by: jeff43222 ]
    Jeff
    EIT (full-time)
    EC (part-time)

  3. #3
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    Would it be safe to say that spa/hot tub would be a continuous load (+3hour), thus be figured at 125%?
    John, Chair City, NC
    Technology: Mans best efforts to make things as good as they used to be

  4. #4
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    The heater will not likely run for more than three hours without cycling off and then on again. The circulating pump will run 24/7, but that is already covered by the motor rules (in 430).
    Charles E. Beck, P.E., Seattle
    Comments based on 2014 NEC unless otherwise noted.

  5. #5
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    Update,

    Recieved pre-delivery info from Hot Springs

    They show #8 wire and a 50A breaker in the main panel feeding a sub panel. Is this not a violation of 240.4 as I dont see any exceptions for hot tubs

    Also, no mention of a EP in the instructions

    If you want to look at the instructions:
    http://www.hotspring.com/cgi-bin/dow...nstruct_05.pdf

  6. #6
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    charlie b
    Here in CT, if you change the water every three months like the instruction recommend, sooner or later you will have to it in the winter. The new water is about 55 degrees, unless you fill it with hot water but with 300 gallons I don't want to do that, in the summer its about 70 degrees. The heat-up rate is about 3 to 5 degrees per hour which means on my unit the heaters and one pump will run much longer then three hours to bring the temp back to 102 degrees. I have found this to be the case on any Hot Tub that I have wired.
    Lou

  7. #7
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    From what I read in part IV in article 680, there is no mention of sizing to 125% so I would go by the nameplate rating for circuit sizing. I don't believe Part 1 of 680 pertains to spas or hot tubs. Please correct me if I'm wrong.
    Tom

    " And all the science I don't understand, it's just my job five days a week "

  8. #8
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    Originally posted by m73214:
    ...I don't believe Part 1 of 680 pertains to spas or hot tubs. Please correct me if I'm wrong.
    See section 680.40 :cool:
    Bryan P. Holland, MCP

  9. #9
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    Thanks.....My bad. What about the circuit sizing? Is the nameplate information adequate or do we go to 125% of the rating? I can't see anything that defines this.
    Tom

    " And all the science I don't understand, it's just my job five days a week "

  10. #10
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    Re: Hot Tub/Spa wire Ampacity and Breaker Size

    According to the Mfg. the electrical requirements are:
    "230 volt, 50 amp Single phase GFCI protected circuit"

    And to further complicate things the diagrams show a 50A breaker with #8 wire

    How do these units ever get a listing?

    They should say: minimum circuit ampacity 40A,
    maximum overcuurent device 50A

    [ January 04, 2006, 03:52 PM: Message edited by: al ]

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