three terminal cord

Discussion in 'General Electronics Chat' started by AHMARAFAH, Aug 26, 2006.

  1. AHMARAFAH

    Thread Starter Member

    Jul 11, 2006
    20
    0
    Hi every body,
    what are the difference between three terminal cord and two terminal cord????
    what are the application that need urgently three terminal one???
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    The third terminal is connected to earth ground. Three conductors are required for safety in any application with a grounded case instead of a double-insulated case.
     
  3. richbrune

    Senior Member

    Oct 28, 2005
    106
    0
    You urgently need the third (ground) terminal on all objects that have a metal case. Most hardware stores carry an adapter to go from the three terminal appliances or equiptment to a wall receptical that has two slots. Cutting the ground terminal on an appliance, tool, or other electrical device can cause a hazardous condition---don't do it.
     
  4. AHMARAFAH

    Thread Starter Member

    Jul 11, 2006
    20
    0
    thank you very much but, what i want to know is:
    i worked with MQ series equipment with three terminal mains cable as follows:
    green/yellow = protective earth(ground)
    blue = neutral
    brown = line (hot line)
    if i connect the line terminal & neutral to 2 terminal cord while leaving the third terminal not connected .Is this condition affects the normal operation of the equipment inquestion?how ??????????
     
  5. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Normal operation will not be affected, but the third wire is there to save lives during a fault condition. People have died because of open or missing grounding conductors. Don't let yourself or your associates join that statistic.
     
  6. Joe S.

    Member

    Aug 28, 2006
    10
    0
    The neutral wire in your building is connected to an earth ground as is the Safety ground wire, the thing is all the power the hot line is carrying is flowing through the neutral at the same rate, so if there is resistance in that line and I guarantee there is, it is hot in relation to actual ground at some measurable level. As far as will an open Safety ground affect the device the answer is, it depends. The metal case or chassis of the device works as an R/F shield in many devices and really needs to be grounded to optimize that. It is important to hook up the Safety ground for Safety sake as well, think about it, copper is selling for about $4.00 a pound on the U S scrap market today, with businesses obsession with maximizing income they would not ever needlessly spend the money if they did not have too.
     
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