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Thread: gfci breaker marina appication

  1. #1
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    gfci breaker marina appication

    nec 555.3 states a marina main over current protection must be gfci protected or individual branch circuits can be gfci
    we are rebuilding a major dock and need to update the service & equipment destroyed by hurricane irma
    i need a 600 A main breaker service and the manufacture ( Eaton) only has a 3 phase breaker available in 600 a, but there is only 1 phase service available. will this work properly to protect the dock pedestals?
    thought about using individual 100 a gfci breakers in the main load center for the pedestals, but they do not make a 100 a gfci breaker either

    help thoughts......... thanks

    mikep elec conn

  2. #2
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    Quote Originally Posted by meleconn View Post
    nec 555.3 states a marina main over current protection must be gfci protected or individual branch circuits can be gfci.
    That's not how I read it. I think every single overcurrent device that serves any feeder or branch circuit must have the 30ma ground fault protection. If you have a load center that has 100 amp breakers feeding groups of pedestals, then the 100 amp breakers need the gfci. If you have a 20 or 30 or 50 amp breaker on a pedestal feeding a receptacle on the pedestal, then those breakers need the gfci.
    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

  3. #3
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    555.3
    1 states that "the main over current protective device that feeds the marina shall have ground fault protection no exceeding 100 mA. that appears to me that it means the 1st or main device needs to have that protection. OR
    2 ground fault protection of each individual branch OR circuit feeder SHALL be permitted as a suitable alternative.

    appears that either way is suitable ?

    the 100 A breakers in the main load center each power a separate pedestal which have 50 or 30 a shore power receptacles in them. seems that if the 100 is protecting the complete pedestal then the outlets should be protected by that also ?

    problem and question is ......having only a 1 phase service incoming main and manufacturer only has 3 phase gfci main disconnect/ MB equipment
    ( this will be on shore at seawall area) (load center is 400 ft away at end of dock)

    trying to figure out if using that 3 phase main, will it protect the single phase load center and branch circuits ? manufacturer does not have a 100 A gfci breaker for branch circuits ( pedestals)

    so now do we use regular breakers in load center & put all gfci breakers in pedestals ?

    just wondering best solution
    thanks

  4. #4
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    OK, I had to look up the current edition of the NEC in Florida. You are on the 2014, and your description of its 555.3 is accurate. I was reading the 2017 edition; everything has changed, and my description is accurate for that edition.

    If you could get a 100ma gfci in your main service disconnect, that would suffice. The question of whether a 3 phase disconnect with a built-in 100 ma gfci would operate properly with a single phase service is one that I suggest asking your Eaton rep.
    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

  5. #5
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    Quote Originally Posted by meleconn View Post

    trying to figure out if using that 3 phase main, will it protect the single phase load center and branch circuits ? manufacturer does not have a 100 A gfci breaker for branch circuits ( pedestals)
    As far as monitoring the lines - it is no different then having all three connected and no load on one of the lines.

    If GFCI "control voltage" is not externally supplied, then you would need to make sure you use which ever poles have control voltage connected to them, could be just one line, or maybe two lines but not likely to be all three.

  6. #6
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    sounds like this will work
    there is no separate control voltage in this application, this is the main feed supplying all the dock pedestals

    separate question........... we will have to connect boat lift motors to the pedestal main lugs, because there is no additional room in the main load center for those breakers. we can use the 25 ft tap rule, there will be a disconnect at the boat lift controller, motors need to be gfci protected also, do we need to make the disconnect a gfci breaker type for that or will the main gfci still protect that as well ? I think the main would suffice and we could just use a NF knife switch disconnect.

    thanks for your help

  7. #7
    I think kwired is talking about the control voltage for the operation of the GFCI circuitry inside the breaker. If it is only powered from 1 or 2 poles you need to make sure you use one of those poles.

    My concern would be cumulative leakage from all docks exceeding 100ma. Nuisance tripping of that main breaker would be a big problem.

  8. #8
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    (2) comments...
    In the past few years there have been numerous dock construction and modification jobs in this area. Then 30ma individual route is more expensive than the 100ma main but the 100 ma main is a PIA for the marinas. It's amazing how many boats have problems that cause the GF to open and when you have one device protecting a large group of receptacles the associated headaches are
    troublesome. I would suggest discussing the pros and cons (nuisance vs costs) with the owner.

    In regard to the lift sub panel, it is doubtful you existing panel has main lugs that are rated for two wires so you might need to find another method to add the tap.
    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.

  9. #9
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    Quote Originally Posted by jstjohnz View Post
    I think kwired is talking about the control voltage for the operation of the GFCI circuitry inside the breaker. If it is only powered from 1 or 2 poles you need to make sure you use one of those poles.

    My concern would be cumulative leakage from all docks exceeding 100ma. Nuisance tripping of that main breaker would be a big problem.
    Yes that is what I was talking about.

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