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Thread: Equipment protection GFCI

  1. #1
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    Equipment protection GFCI

    Our busses have blockheaters and we have installed sub panels and Eaton GFCBconnected to long extension cords.
    The cords will be unplugged and plugged in in between trips in wet and snowy conditions.
    They trip often I was wondering if I swapout the GFCB with a GFEP equipment protection GFI would that be
    in accordance witharticles426 and 427 in the NEC.

  2. #2
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    Quote Originally Posted by Adams14 View Post
    Our busses have blockheaters and we have installed sub panels and Eaton GFCBconnected to long extension cords.
    The cords will be unplugged and plugged in in between trips in wet and snowy conditions.
    They trip often I was wondering if I swapout the GFCB with a GFEP equipment protection GFI would that be
    in accordance witharticles426 and 427 in the NEC.
    That is a negative, Ghost Rider. ground-fault equipment protection has a 30 or higher cut off, GFCI is for people and has a 6 milliamp cut off. You cannot substitute one for another here. there is a very recent thread on block heaters tripping out, have a look at the suggestions there. My initial thought is to have each GFCI only serving one extension cord and one block heater so that a collection of very minor ground faults will not trip the receptacles. That and to have extension cords in good condition. Check the connections on the equipment too.

    Unless articles 426 and 427 has been expanded to include engine block heaters, they're not applicable. The main whammy is 210.8, you are not going to get around that.
    Electricians do it until it Hertz!

  3. #3
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    Rereading your post, it seems to me you have a GFCI circuit breaker protecting standard receptacles. I would rewire this to have a standard breaker feeding GFCI receptacles that are not daisy chain off one another.

    If you have six buses, each with a 1 milliamp ground fault, you are going to (or should) trip that breaker every time. If they are fed from six separate GFCI receptacles, that 1 milliamp ground fault is not an issue. That is not to rule out the possibility of having a fairly major ground fault in one or more of the buses or the extension cords to their block heaters, however if these are not tripping right away, I would be inclined to think that a very small leakage from each is accumulating or adding up and tripping the GFCI breaker.

    Also, some manufacturers limit the length of wiring Downstream of their GFCI devices... This is another reason for GFCI receptacles over Breakers, and to limit your extension cord lengths to as short as practically possible.
    Electricians do it until it Hertz!

  4. #4
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    As others have suggested. One block heater per GFCI. Dependent on the heater size, one per circuit might be you limit as well.
    Tom
    TBLO

  5. #5
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    Quote Originally Posted by JFletcher View Post
    That is a negative, Ghost Rider. ground-fault equipment protection has a 30 or higher cut off, GFCI is for people and has a 6 milliamp cut off. You cannot substitute one for another here. there is a very recent thread on block heaters tripping out, have a look at the suggestions there. My initial thought is to have each GFCI only serving one extension cord and one block heater so that a collection of very minor ground faults will not trip the receptacles. That and to have extension cords in good condition. Check the connections on the equipment too.

    Unless articles 426 and 427 has been expanded to include engine block heaters, they're not applicable. The main whammy is 210.8, you are not going to get around that.
    Each circuit is dedicated to one block heater, the supply hard wired 10 to 40 foot of SOOW cord with strain relief at subpanel at the end of cord there is a weather tight 5-20R
    Attached Images Attached Images  

  6. #6
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    Look at the thread titled "Block Heater Tripping GFCI".

    Never seen an installation like what you described, it may violate 400.7 or 400.8. that aside for a moment, I would make a note of what buses trip on what receptacles. if it is all of them, I would look at the most likely connection point to cause the ground fault trip which is where the plug of the engine block heater goes into the receptacle on the cord end. Other places to check are the plugs on the block heaters themselves, look for abrasions or corrosion. I would also check the panel for corrosion and look for any signs of water infiltration or corrosion on the terminals.

    While going to GFCI receptacles would not shorten the wiring run any in your case, it would allow you to use a factory extension cords with molded factory ends on them which are in my opinion more water resistant than any field-made cord. How old are those cords? If the ends have ever been run over by a bus, or the bus moved while the engine block heater was still plugged in, there could be damage to the fine stranded conductors within the cord.

    Please post any problems and solutions you find with your installation. The temptation to use GFEP breakers over GFCI is there, though there is the possibility that even those will trip, and then what? Yank them out and put in regular breakers? Neither solution is allowed per the NEC.

    Good luck.
    Electricians do it until it Hertz!

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