For example, if you need to work on a light switch, shut off the power to the switch’s circuit, then carefully remove the switch cover plate. Touch the probe of a non-contact voltage tester to each switch terminal and to every electrical wire in the box to make sure no voltage is present. You never know when a tool might slip or drop and make an accidental electrical connection. Insulated tools have a minimal amount of exposed metal to prevent such catastrophes. If you’re working on or near electrical wiring or equipment from a ladder, use a nonconductive fiberglass ladder instead of a metal ladder. Capacitors store electricity to help motors start up by giving them a boost at high voltage. They can deliver a deadly shock even when the circuit power is off or the appliance is unplugged. Do not work on appliances or other equipment that contains capacitors unless you know how to discharge the capacitors safely. GFCIs detect electrical faults and shut off the power to prevent shock. Faults can be caused by things like water getting on cord contacts or by short circuits occurring inside tools, cords, or appliances. GFCI protection is especially important when working outdoors or near any moisture, but it’s always a worthwhile safety precaution. If you unplug the device while it’s on, the flow of electricity might create an arc, which is the electricity literally jumping across the gap from the outlet to the plug. This is normally safe to do with lamps and small appliances that don’t have ON/OFF switches, but large appliances, like dryers, ranges, AC units, and even electric heaters, can create dangerous arcs when disconnected or connected under load. There is a modern electrical code requirement for a special breaker to reduce and prevent arc faults. Arc-Fault breakers trip much quicker than conventional breakers to reduce fire hazards from arcing circuits.
