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Old 03-23-2010, 09:20 PM   #1
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External Ground


Dumb question. Is there any advantage to connecting an external ground for my washing machine and gas dryer? Both units have a 3 prong cord. The outlet is grounded. I did a continuity check from the ground off of the electrical outlet to the cold water pipe. 0 ohms. Wasn't sure if having an external ground provided additional safety / backup?
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Old 03-23-2010, 09:58 PM   #2
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If the cord is properly connected to the machine, and the receptacle is properly connected and bonded, then I say there is no advantage to an external ground. Because of the poor conductivity of the earth, earth connections really provide little safety in the event of a fault.

The only advantage I can think that an extra earth connection would bring would be in the event of your machine receiving a direct lightning strike. What are the odds of that?
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Old 03-24-2010, 08:29 AM   #3
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If another ground rod is driven, it should be connected to the electrical system in the same manner the first ground rod and/or the incoming water pipe is so bonded, using a #6 copper wire. (A #4 wire is needed when the service is over so many amps, I forget the number.)
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Old 03-24-2010, 10:10 AM   #4
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If you are asking about the small green wire that some machines had that connected to the screw on the trim plate the answer would be no. It is not needed. The third prong in the cord covers that function in a properly wired system.
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Old 03-25-2010, 11:34 AM   #5
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Thanks!
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