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Thread: GFCI minimum trip rating

  1. #1
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    GFCI minimum trip rating

    Does anyone know the minimum trip rating for personal protection on a GFCI? Is there a different min. trip rating for equipment protection? Can you get GFCI's with different trip ratings? (I beleive the standard is 6 ma), but can you get one that trips at 9 ma and is still legal?

  2. #2
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    4-6 mA. See the FPN to GFCI in Article 100 of the NEC.
    Bryan P. Holland, MCP

  3. #3
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    4-6ma is the only range acceptable for personnel protection.

  4. #4
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    Quote Originally Posted by SiddMartin View Post
    Does anyone know the minimum trip rating for personal protection on a GFCI? Is there a different min. trip rating for equipment protection? Can you get GFCI's with different trip ratings? (I beleive the standard is 6 ma), but can you get one that trips at 9 ma and is still legal?
    The equipment ground protection is designed to protect the equipment and not personnel. The ground fault setting depends on the size of the equipment and the circuit to which it is connected. These setting are usually high enough to kill a person.

  5. #5
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    I agree, Class A GFCI's trip between 4-6 ma. Older Class B GFCI's trip at a minimum of 20 ma and are not suitable for personal protection. GFPE protection used for protecting equipment will trip at 30 ma.
    Rob

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    All responses based on the 2011 NEC unless otherwise noted

  6. #6
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    Quote Originally Posted by infinity View Post
    I agree, Class A GFCI's trip between 4-6 ma. Older Class B GFCI's trip at a minimum of 20 ma and are not suitable for personal protection. GFPE protection used for protecting equipment will trip at 30 ma.
    I believe Class B GFCI's were for old pool lighting fixtures.
    Just because you can, doesn't mean you should.

  7. #7
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    It may be 4-6ma but what's the allowable trip time? I don't have a link handy for one of those charts. You may be surprised at the lenght of the allowable trip times!
    Bill

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    Quote Originally Posted by wptski View Post
    It may be 4-6ma but what's the allowable trip time? I don't have a link handy for one of those charts. You may be surprised at the lenght of the allowable trip times!

    According to P&Ss website, the trip time is 0.025 seconds nominal.

  9. #9
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    Quote Originally Posted by jim dungar View Post
    I believe Class B GFCI's were for old pool lighting fixtures.
    That's correct. Dates back to the 70's I believe.
    Rob

    Chief Moderator

    All responses based on the 2011 NEC unless otherwise noted

  10. #10
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    Quote Originally Posted by 480sparky View Post
    According to P&Ss website, the trip time is 0.025 seconds nominal.
    The current and time are like two different things. I can't find one of those current vs time curves but somebody stated 6ma at 7.2 seconds which is what I'm getting at. I tested some P&S and Leviton a while back. The Leviton's trip time was over .1 seconds.
    Bill

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