I walked in and killed the main breaker. I pulled the switch out and held a magnifying glass to the side of the nylon body of the switch. There it was. A crack no wider than a human hair, running from the hot screw to the ground yoke.

Electricity is invisible. Safety is visual. Don't just look at the wires; stare at the cracks.

See the Electrical Crack: Why the Smallest Flaw Can Spark the Biggest Disaster

Whether you are a master electrician or a DIY weekend warrior, the most dangerous enemy isn't voltage—it's entropy. It is the microscopic fracture that grows into a house fire.