GFCI trips when reading voltage

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Old 11-26-16, 11:06 AM
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GFCI trips when reading voltage

Not sure what's going on, but when I check voltage in this circuit to ground reference, the gfci trips. If I check voltage to neutral reference, it does not.

Basically, why would simply trying to read voltage trip a gfci?
 
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Old 11-26-16, 11:23 AM
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Welcome to the forums.

Basically, why would simply trying to read voltage trip a gfci?
A GFI measures the inbalance between hot and neutral. So if you test from hot to ground with a heavy enough load.... the GFI will trip due to the hot/neutral inbalance.
 
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Old 11-27-16, 06:31 AM
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GFCI's that are for protection of personnel (standard GFCIs) will trip on 4-6 milliamps. The GFCI is doing exactly what it is supposed to do.
 
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Old 11-27-16, 01:19 PM
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The act of reading a voltage draws a small amount of current.

A typical digital voltmeter draws a much smaller current than a typical analog (swinging needle) voltmeter where the latter might draw enough to trip the GFCI unit.
 
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