We're sorry, but OSHAcademy doesn't work properly without JavaScript enabled. Please turn on JavaScript or install a browser that supports Javascript.

160 Tool Safety: Basic
Skip to main content

Grounding

The term "ground" refers to a conductive body, usually the earth. "Grounding" a tool or electrical system means intentionally creating a low-resistance path to the earth. When properly done, current from a short or from lightning follows this path, thus preventing the buildup of voltages that could otherwise result in electric shock, injury, or death.

Grounding-type corded tools must have an intact equipment-grounding conductor.

Under certain conditions, even a small amount of electric current can result in heart fibrillation and death. An electric shock also can cause the user to fall off a ladder or other elevated work surface and be injured due to the fall.

Electric power-operated tools used in construction must either be approved double-insulated tools or be grounded in accordance with OSHA's construction electrical requirements. Common protective methods include the following:

  • using a three-wire cord connected to a properly grounded receptacle
  • using an approved double-insulated tool

Three-wire cords contain two current-carrying conductors and a grounding conductor. Any time an adapter is used to accommodate a two-hole receptacle, the adapter wire must be attached to a known ground. The third prong must never be removed from the plug.

Knowledge Check Choose the best answer for the question.

2-6. What should never be done to a grounding-type plug?