Ground/Earthing?

Discussion in 'General Electronics Chat' started by therock003, Feb 2, 2009.

  1. therock003

    Thread Starter Member

    Jun 25, 2008
    13
    0
    Sorry guys but what's the significance of earthing and grounding?

    Does it prevent human electrocution and protects electrical devices? I've seen some schematics/diagramms where ground is shows, or on cables carrying video signals, pins some pins are labeled as ground.

    I want to know more of the application and the meaning of all this.

    I'm fairly new with the concept of electricity, so i do apologize for these beginner's questions. :(
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    "Ground" is a multivalued term. In reference to a circuit, it might be more accurately expressed as circuit common, as it defines the point of reference for the measurement of all voltages.

    For household wiring, it's different in that it is a reference point for measuring, but serves a different purpose from the AC common line. The AC common (white wire if wired properly) attaches to the ground in the distribution panel. AC common, or neutral, carries current - ground does not.

    The protective aspect is in insuring that the ground wire is electrically bonded to metallic chassis and cases, so no shock hazard can happen if there is an internal wiring fault. The protective action comes from insuring that there is no difference in voltage between you and the metallic surface you come in contact with.
     
  3. Tesla00010010

    Member

    Jun 20, 2008
    21
    0
    You can think on earth as a massive supply of electrons,this means if you touch a wire or a metal case that is energized, and it is connected to ground,you will be shortcircuited by the ground and no current will pass through your body.However,this also means only one part of the circuit can be grounded so care must be taken when working on the "hot" wires.
     
  4. StephenDJ

    Active Member

    May 31, 2008
    58
    0
    If say for example, computer equiptment is connected to AC mains by a three-conductor plug, it's possible that the case of the computer might also be connected to AC ground via the third conductor (ground) on the plug, although I'm not sure if that is always the case with every piece of equiptment.
     
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