The Argyle Sweater by Scott Hilburn for June 15, 2010

I used to work on Hotel Computer systems including active phone switches. I got called to a site on day because the phone switch kept resetting and dumping out going calls. First thing I did was check the power and while I was watching, the input power dipped from 120 down to about 40 volts for a second or so, then came back up to 120. The switch was supposed to be on a dedicated power circuit, so the hotel’s electrician said it was the switch drawing down the power for some reason. I knew this wasn’t possible because it couldn’t draw a big enough load to do that. Lo and behold, the hotel’s chief engineer got the electrical plans out, and found that an outlet on that circuit ran to the garage area. When we traced it out, a refrigerated truck was plugged in on that outlet and every time the compressor kicked on, we got the power fail mode on the switch. The electrician disconnected the outlet and burned off the leads so no one could put an outlet there any more. It only cost the hotel 4 hours of my time which I’m sure they recovered in phone revenues by the end of the week.