Ways to Prevent Electrical Shock

Turn off the Power

Always shut off the power to a circuit or device that you will be working on. This usually means turning off the appropriate breaker in your home's service panel (breaker box). If you're working on an appliance with a cord, unplug the cord to shut off the power to the appliance.

Test for Power

Always test for power at the device or equipment after turning off the circuit breaker. Use a non-contact​ voltage tester (or another type of electrical tester) to check the circuit wiring and any electrical contacts before touching anything that may carry electricity.

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.

Use Insulated Tools

It always makes sense to use insulated tools for electrical work. Since you've shut off the circuit and tested for power before touching any wires, using insulated tools may seem like overkill, but consider it an easy—and potentially lifesaving—backup precaution.

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.

Beware of Capacitors

Capacitors are like batteries in that they hold an electric charge on their own. They are often found in appliances and other equipment that uses motors, such as air conditioners, refrigerators, freezers, garage door openers, and microwave ovens.

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.

Protect Yourself With GFCIs

If you're doing work that uses electricity—that is, with the power on—plug your extension cord, power tool, or other equipment into a GFCI (ground-fault circuit-interrupter) outlet, or use a GFCI-protected extension cord.

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.

Never Connect or Disconnect Under Load

When an appliance or other device is wired or plugged into a circuit and is running, the circuit is "under load." That means the device is drawing power and electricity is flowing from the circuit into the appliance and back onto the circuit wiring in a continuous loop.

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.