Anyone care to guess why the voltage drop was so high when measured at this receptacle?
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(Seems I can’t post a pic. My Suretest measured 74 per cent VD)
Your Suretest is broken?
The wire is too long?
There is too much draw?
The wire is too small?
Okay, they’re just guesses.
Others will have more guesses. 
Loose connection?
Oxidation?
The problem turned out to be a faulty breaker. It had developed a high resistance and when the light was turned on it dimmed for a few seconds before coming on to full brilliance. The side breaker showed signs of heat build up right where the contacts would be inside it. Was a fire waiting to happen.
Most common cause when I see this is too small of a conductor wire. Big houses with long runs to the receptacles, etc.