[micro_softy]

I have a similar issue.

Sometimes, but not every time, when I turn on a particular halogen lamp using the same outlet as a particular computer, it triggers USB detection and I get kernel messages on /dev/console as if I was plugging in a USB device.

This is a BSD kernel.

[svckr]

Now, if you had some kind of home automation switching the lights you could implement a really slow communication protocol as a USB device driver.

[boomboomsubban]

This was happening to me, there was some problem with the electricity in my apartment. I can't recall what the electrician said, there were some switches that only 1/4 were working, and if 2/4 had been it would have fried everything. They fixed it in about an hour.