Just because you threw the switch, it doesn’t mean it’s off!
Electrical shock can cause serious injury and even death. So when working with electricity, the only way to prevent shock is to make sure the power is off. Sacramento, California electrical contractor Cliff Popejoy demonstrates a few procedures that, when followed, will guarantee your safety and the safety of those you work with.
For more wiring information, read Cliff’s article Retrofitting Recessed Lights.