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Thread: How far is too far for GFCI Protection

  1. #1

    Default How far is too far for GFCI Protection

    Was just wondering if you were protecting a bunch of downstream receptacles from the load side of a gfi or a breaker gfi is there a limit to the distance from the gfi before you might expierence a current abnomally that might cause a trip at your gfi? I know you will have voltage drop but was wondering if anything happens to current that the gfi may interpret as a leak......RL

  2. #2
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    Default

    Do not know of any such problem arrising.

  3. #3
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    Default Gfci

    The GFCI will remain fine, as long as you have wired the circuit with AWG specified for that circuit, and distance.

    Example: A GFCI wire with 14 AWG for a 200 foot run will not (In my opinion) protect the loads of that circuit properly do to voltage drop. In theory: The Electrons loose energy by giving it up to resistance--in the form of heat.

    In theory: The more loads there are, the less voltage drop.

    This is open for debate!
    Learning brings success. While you are waiting, I'm getting better!

  4. #4

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    GFCI should remain fine - voltage drop can always be a consideration but should be equal for equal wire size and distance - I think GFI works by looking for current leakages i.e. current in hot wire not the same as neutral wire (within some very small number) and will trip if that value is exceeded.

    p.s.: I think you meant that the more loads, the higher the drop.
    Last edited by Frank; February 5th, 2004 at 04:45 PM.

  5. #5

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    Thanks for the replies this was just one of those questions that pop into your head when its snowing outside and you have the fireplace burning. This is probably more of an impractical question than theoretical. I did some research and couldnt find anything that addressed the possibility of current leakage in long runs of wire and gfci's. Was curious since voltage and resistance change with distance and number of loads that current has to change also and may trip the gfci if something going on with current that isnt the norm.....RL

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    Default Loads

    You may be right on the Voltage drop Frank. Yet I believe my statement is true, but it may have applied to series circuits??? Will have to read on this theory topic. Yet, as you and I stated, "distance and wire size--sized for that distance, does play a role."

    Interesting!<<topic of load>>
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    Quote Originally Posted by Ohm1
    You may be right on the Voltage drop Frank. Yet I believe my statement is true, but it may have applied to series circuits??? Will have to read on this theory topic. Yet, as you and I stated, "distance and wire size--sized for that distance, does play a role."

    Interesting!<<topic of load>>
    A larger load draws more current, dissipates more power, and creates more voltage drop in the circuit supplying it. Just remember that loads are added in parallel to a branch circuit so as the load increases the circuit's impedance/resistance decreases.

    Just a little bit of theory.

    Homer
    Last edited by Homer; February 5th, 2004 at 09:52 PM.

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    Default Noted

    Well Stated Homer!

    To add:
    It is stated in theory that loads connected in parallel: Voltage is also dropped across each load (as in series). Instead of a portion of the source voltage being dropped across each load as in a series circuit, however, the entire source voltage is dropped across each. Noting that parallel circuits (as acknowledged) are connected together directly across the power source.


    Yet, in a series circuit, the total voltage dropped across all of the loads is equal to the source voltage. This being true rather one load or more. Seeing this, we can say that for a fixed source voltage, the more loads there are, the less voltage drop across each load. [Credit: Mileaf]
    Learning brings success. While you are waiting, I'm getting better!

  9. #9

    Default

    Ohm, there seems to be some confusion or misquoting or lack of accuracy on this subject.

    First a GFI does not care how far it serves. It is looking for leakage between the hot, grounded leg, equipment ground. While voltage drop may have some affect it is not primary concern with GFI protective device.

    As for the voltage drop decreases with the more loads applied, this is inaccurate.

    You are confusing house wiring loads and resister calculations parallel and series.

    If house wire the more total load from source of power to end of line the more voltage drop will appear on that line decreasing voltage after each load being applied.

    Now series resisters and parallel resisters are different in voltage at end of line.

    A resisiter placed in series from a power source to a load will drop that rating of that resister.

    However a resister placed in parallel of a circuit will drop that rating of only 1/2 of that resister.

    See the following parallel / series resister article linked below;

    http://www.homewiringandmore.com/hom...lelseries.html

    Hope this helps

    Wg

  10. #10

    Default

    I understand that if GFCI protection (breaker or receptacle) is installed far from the actual electrical load, there may be a chance of false trips due to induction and leakage imposed by, and on, the cable and its conductors to the load. This seems to be more prevalent when the circuit is run outdoors, where the environment changes often.

    Below is from an article in an electrical trade magazine:
    Length of circuit. A GFCI is subjected to tests that simulate long branch circuits. While there are no specific rules concerning the length of the circuit protected or the number of receptacles on the protected circuit, remember that the GFCI will add up all the harmless leakage currents and capacitive leakages. Under extreme circumstances, this could "preload" the GFCI and make it appear overly sensitive or, worst case, result in nuisance tripping. Therefore, you should minimize the length of circuits to the degree possible.
    Last edited by Ron; February 6th, 2004 at 07:46 PM.
    Ron

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