On 2013-05-18 03:59:39 +0000, Fred McKenzie said:

Billfre-

Also look for evidence of a poor neutral connection. When that happens,
voltage will divide according to the load on each line. If that were
the case, ten volts drop at a high current load could cause a ten volt
rise across the other line-to-neutral circuit.

Five or ten volts doesn't sound like a serious problem, but a poor
neutral connection could get worse with age.

Fred

Fred,

Thanks for that tip, I think it may be the problem here. I went back
and tightened the screws on both leads at the outlet and at the hot
side on the breaker. One screw at the outlet tightened maybe a quarter
turn. This brought the voltage drop down from 10v to 7v. Still over
the 5% specified by code. I also put a voltmeter on another outlet in
the same room that was on a different breaker. When I loaded the
outlet that had the 7v drop, the voltage at the other outlet went up a
couple of volts from 120v to 122v and I wondered, what could cause that?

Then you posted about the poor neutral and I thought about the 2v rise
I had measured at an adjacent circuit. Then remembered that I did not
check tightness of the neutral wire connection in the panel. Think I
will go back again and make sure the neutral wire is good and tight at
the panelboard. Maybe that is why it is still over the 5% drop spec.

Does this make sense?