A friend was replacing a light fixture in his bathroom and ran into something confusing–a red wire in the electrical box along with the usual black and white wires. And when he hooked up his new light fixture, he did what I would expect the majority of homeowners to do. He connected the white wire on the fixture to the white wires in the box, and the black wire on the fixture to the black wires in the box. And then his light switch wouldn’t work. The light stayed on all the time. He was on the right track when he asked what the red wire is for.
It turns out the red wire was the key to solving his light fixture problem.
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.