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  1. #1
    Join Date
    Nov 2007
    Location
    Pennsylvania
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    246

    Question Purpose of ground connection.

    I just like to know what happen if the ground wire for wall switch and outlet isn't connect.

    FYI.... I did not leave any ground wire disconnect. I found 2 more wall switches and outlets that aren't connected in the first place. I did the proper repair and everything is peachy but I'm just wondering why it wasn't connected in the first place.

  2. #2
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
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    5,836

    Default Re: Purpose of ground connection.

    The ground wire is a saftey feature but has little to do with functionality of equipment pluged into the outlet with the posible exception for electronic equipment which uses ground connection for some filters. If they were in the box but not connected someone got lazy.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  3. #3
    Join Date
    Aug 2007
    Location
    The Great White North
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    Default Re: Purpose of ground connection.

    The purpose of the ground wire is .... To create a safe low restriction path for a fault condition to trip a breaker or fuse.

    In a normal condition the ground conductor is not a path for current flow.

    In an abnormal condition ..... the ground conductor is the fault path for stray current


    A receptacle will still function without a ground wire attached ..... but if you had plugged a 3 prong device into an ungrounded receptacle and if there were a short between the hot wire and the case or chassis (ground) the breaker wouldn't trip until you touched the device.

    You would become the fault path for the overload to trip the breaker or fuse.

    Electrocution occurs when a small, specific amount of electrical current flows through the heart for 1 to 3 seconds. 0.006-0.2 Amps ( 6-200mA milliamps) . An example of how small an amount of current it takes to kill ..... a 15 Watt night light draws about 125mA.

    Side note :

    There is the issue of "ground fault" existing when an ungrounded (hot) conductor comes in contact with the metal frame or chassis of a 2 prong device.... like a toaster which is not grounded.

    For example ...the hot conductor has frayed where it enters the toaster . There is now a potential for electricity to flow between the chassis of the toaster and any grounded surface that it might become connected to. In this case when you touch the hot chassis of the toaster and grounded metal plumbing ...the human body is conductive ...you have provided a conductive path between the "hot"(energized) toaster chassis and ground .... A GROUND FAULT is occurring.

    Tid bit .... Toasters are intentionally not grounded so that when a person starts forking around for a stuck piece of toast and they make contact with the heating element, they won't provide a fault path from the energized fork, hand, and a grounded metal enclosure. This is one reason countertop receptacles are being required to be GFCI protected.

    BigWalt .... sorry for the long winded answer to a simple question.
    Last edited by canuk; 12-11-2007 at 09:08 AM. Reason: additions

  4. #4
    Join Date
    Aug 2007
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    Default Re: Purpose of ground connection.

    Geez ... Jack you sneaked in again ... well it's no wonder with the novel I wrote.

  5. #5
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
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    Default Re: Purpose of ground connection.

    Canuk,
    Your posts are starting to look like someone elses that we know and love.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  6. #6
    Join Date
    Aug 2007
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    The Great White North
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    Default Re: Purpose of ground connection.

    Yep ... it is frightening.

  7. #7
    Join Date
    Aug 2007
    Location
    The deep South
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    459

    Default Re: Purpose of ground connection.

    canuk , my friend , I'll have to take exception with the first sentence of your post . The ground wire has nothing to do with the path for current flow during normal conditions . This is the job of the neutral conductor . Other than that , good job !

  8. #8
    Join Date
    Aug 2007
    Location
    The Great White North
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    Default Re: Purpose of ground connection.

    djohns .... thanks for pointing out it wasn't clearly stated.

    I inserted these to clarify.
    In a normal condition the ground conductor is not a path for current flow.

    In an abnormal condition ..... the ground conductor is the fault path for stray current.
    This link has an example of when a receptacle does not have a bonding jumper between it and the box : http://www.neccode.org/newsletters.p...y&letterID=241

    Some light reading:
    http://www.iaei.org/subscriber/magaz...c/gregorec.htm
    Last edited by canuk; 12-11-2007 at 08:52 PM.

  9. #9
    Join Date
    Aug 2007
    Location
    Denver, CO
    Posts
    666

    Default Re: Purpose of ground connection.

    Good stuff.

    Another way to think about a “ground” wire is that it is little more than an alternative “neutral” wire or “intentionally grounded conductor” which is what a neutral wire is.

    At some point on the electrical service to any given structure the neutral and ground are bonded together at one and only one point on most electrical services.

    And, as has been so eloquently pointed out the ground wire provides a path to clear unintentional faults between ungrounded conductors and grounded ones.

  10. #10
    Join Date
    Aug 2007
    Location
    The deep South
    Posts
    459

    Default Re: Purpose of ground connection.

    canuck , I read your post again and it makes sense to me . I was refering to a NORMAL overload condition and you were talking about a fault . Notice the time of my post . 5:48 AM I had just gotten to the shop and turned on the computer . The coffee wasn't even ready yet .

    I stand corrected and promise never to post that early in the morning ever again .( at least not before I've had my coffee )

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