I was having a problem with voltage drop after putting in a new heat and air system. had the guy from the power company out to tighten the line along with me tightening my panel. I am still not sure if mine is solved but he said he went to one call and the customer said when they flushed the toilet that his security light went out.
The problem was found to be the well pump was causing enough drop that his HID light would go out.
Pretty funny story that I am sure has been told more than once but I wanted to hear it again.