Checked a job that the voltage on one circuit will run about 117v, then will drop down to 112-113v for a couple seconds, the current jumps up from about 12a to 17-18amps at the same time not long enough to trip the (battery back-up, (kicking on I believe), 119-121v on other circuits at panel.
Do I understand this correctly? Measured at the panel, a circuit with a 12 A load, measures 117 V, which then drops down to 113V when the load jumps up to 18 A. Other circuits on the SAME PHASE read about 120 V.
If all of the above is true, I would suspect a loose connection between the breaker and the buss bar, a defective breaker, or loose connection at the breaker.
Other possabilities include measuring Voltage or Current with a non true RMS meter. I included this because you stated that the load is a UPS feeding a server.
Larry C
