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Andy Peters
05/16/12 21:31
Read: 397 times
Tucson, Az
USA


 
#187387 - ground fault
Responding to: Joseph Hebert's previous message
Joseph Hebert said:
Hi Erik,

I'm guessing then that you distinguish a short from a leak based on the impedance to ground? Or just the resistive component? At how many ohms does a short become a leak? I think of a high impedance short, not a high impedance leak, and so I don't worry about the qualitative distinction.


"Ground fault" is somewhat of a misnomer.

The usual GFI circuit looks at the currents in the hot and the neutral, and if they are not equal (which is what you expect, the neutral of course is the return for the hot), the circuit assumes that the current is going elsewhere which is bad, and it trips. This is why a GFI works, even when the grounded conductor is absent or defeated.

-a

List of 11 messages in thread
TopicAuthorDate
Ground Fault      Arif Deshmukh      05/15/12 09:12      
   who know      Erik Malund      05/15/12 09:23      
   3 hooters?      Per Westermark      05/15/12 09:28      
      I was thinking more of this      Jez Smith      05/15/12 11:50      
         with a slight twist      Erik Malund      05/15/12 12:18      
   ground fault      Joseph Hebert      05/15/12 15:28      
      actually      Erik Malund      05/16/12 06:36      
         how do you distinguish?      Joseph Hebert      05/16/12 21:10      
            ground fault      Andy Peters      05/16/12 21:31      
               ground fault      Joseph Hebert      05/17/12 07:24      
      Thanks Joseph Hebert      Arif Deshmukh      05/16/12 23:52      

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