We just moved into our house and the previous owner remodeled the master bathroom. There is a GFCI outlet in the master bathroom and it was ungrounded and I took it out and discovered that the ground wire was wired in with the neutral wire.
With my multimeter I measured 125.9V from hot to ground (this is good), 4.92V from hot to neutral (it should be around 120V), and 123.8V from neutral to ground (it should be around 0). I think these readings indicate an open neutral between the GFCI and the breaker panel.
This was a remodel job, and the GFCI wasn't there before the remodeling, and no new outlets were added between the master bathroom and the garage, which is where the breaker panel is located. There is a utility room between the master bathroom and the garage and there is nothing new in the utility room; no new outlets, and everything in there works when the two master bathroom breakers are turned off. There are no new outlets in the garage, either. I'm praying that there is not a disconnected neutral wire in the walls or ceiling.
And so my question is, "How do I check for the open neutral in the breaker panel? Do I look for a loose white wire or screw at the 2 master bathroom breaker switches? Do I measure with my multimeter? Where do I put the red and black probes? Would I get the same reading as I did at the GFCI outlet? Should I leave the power on? Is that safe as long as I don't touch the wires?"