I was recently doing some rewiring to install dedicated circuits for networked Computer equipment. I was looking for a certain breaker (should have been marked) to turn off approx 5 duplex receptacles which had 2 Computer/Monitor/UPS systems and 1 Adding Machine.
After going through every breaker 3 times and following wiring (visible entire length) I found that it was already on it's own Breaker. We finally found that after the breaker for that circuit was turned off, it took 5 - 10 seconds for the voltage to go down! After unplugging the small UPS unit I immediately tested the prongs on the plug and found that somewhere around 110v was being backfed through the plug! and into the receptacle!
Has anyone had a similar experience?
