How To Protect Against Energized Parts And Unexpected Startup
Protection from Energized Parts
A break in an electric tool’s or machine’s insulation can cause its metal parts to become “hot” or
energized, meaning that they conduct electricity. Touching these energized parts can result in
an electrical shock, burn, or electrocution.
The best way to protect yourself when using electrical tools or machines is to establish a low resistance path from the device’s metallic case to the ground. This requires an equipment
grounding conductor, a low-resistance wire that directs unwanted current directly to the
A properly installed grounding conductor has a low resistance to ground and greatly reduces
the amount of current that passes through your body. Cord and plug equipment with a three prong plug is a common example of equipment incorporating this ground conductor. Never use a three-prong plug if the center ground prong is missing.
Another form of protection is to use listed or labeled portable tools and appliances protected
by an approved system of double insulation or its equivalent. Where such a system is
employed, it must be marked distinctively to indicate that the tool or appliance uses an
approved double insulation system.