Electric Grounds-(not coffee grounds)

[Gregg]

How do you know if a circuit is grounded properley?  This is the third time I have run into this situation.  Each time it is on a 240v circuit.  All checks out fine on the multimeter when testing.  The appliance does not work right.  Twice now on dryers and once with a range.  At first it seemed to be a bad motor in the dryer.  Would only hum when start was pushed.  Bring the dryer somewhere else and it works.  An electrician eventually found a bad ground outside the house.  Similar problem with a range at another locaction.  Again range worked back at my shop.  Electrician found  a bad ground under the house(mobile home). Seem like the problem only shows up under a load.  Anyway for me to know this before extensive testing on the appliance and dragging it to another location? Thanks  Gregg

[Samurai Appliance Repair Man]

The easiest thing to do would be a wire a test lamp from leg to neutral and then from leg to ground. The lamp should light both times. This test proves that the circuit has power, not just voltage.

[fool4jesus]

Sounds like in each case, the house's ground (or more likely the neutral) was not at zero due to the bad grounding spike. I believe most dryers and ranges are both 110/220V, so the neutral would be the problem.

What I hear you saying is you want to know if the appliance is actually ok, so you can point to a possible problem in the house wiring. If so, seems like that would be difficult to test in the home because the resistances inside the appliance could be perfect but the appliance still broken.

There are methods of testing the ground in the home, but I am not familiar with any real easy ones. See http://www.faqs.org/faqs/electrical-wiring/part1 for some information on the subject under the heading "Testing grounding conductors and grounding electrodes."