From: jerry@example.invalid   
      
   Peter W.  wrote:   
   >> I don't understand how that small voltage drop in the cabling causes an   
   imbalance in current. The earth in all appliances is supposed to be fully   
   isolated from the hot/neutral isn't it?   
   >   
   > A sensitive GF device will detect a difference between flow to the neutral   
   and the ground, and perceive this as current going to ground.   
   >   
   > The ground and neutral are bonded within the main panel, and there is a   
   secondary ground feeding the main panel.   
   >   
   > So, the full path of each circuit Neutral is from each device to the panel,   
   where it is bonded to a local ground. From there to the Utility Transformer -   
   which is also grounded in its location.   
   >   
   > The full path of each circuit Ground is from each device to the panel, where   
   it is bonded to the neutral and a local ground. It stops at the local ground.   
   >   
   > In theory, the Neutral and the Ground should be at equal potential - thereby   
   avoiding false trips - as that is what the GF device is looking for - current   
   going to Ground (or somewhere), not Neutral. If the Ground and Neutral are not   
   at equal potential    
   - there may be something for the GF device to detect.   
   >   
   > Peter Wieck   
   > Melrose Park, PA   
      
   This make no sense, the GFCI doesn't care about the ground wire, it   
   measures the difference in current between the 2 supply wires.   
      
   Look up a datasheet for the LM1851 IC, it will show sample circuits   
   for a GFCI, there's no connection to the ground wire at all. In fact   
   you can use a GFCI on an ungrounded circuit and it's still functional.   
      
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