Non-double-insulated power tools must use what kind of plug?

• A. Two-Prong Plugs
• B. GFCI Plugs
• C. Wire Guard
• D. Three-Prong Plugs

Answer: (D)

Non-double-insulated tools are designed with a protective earth path to safely carry fault current away and reduce the risk of electric shock. That grounding path is provided by a three-prong plug, which includes a ground pin connected to the tool’s chassis and to the electrical system ground. If a fault occurs, the current has a safe route to ground and the circuit will trip to disconnect power. A two-prong plug lacks this grounding connection, increasing shock risk. GFCI protection is important in wet locations, but it is a separate safety feature and does not replace the need for a grounding plug. The three-prong plug thus is the correct choice for non-double-insulated tools.