Electricity and Safety: Understanding Three-Prong Plugs

Why do power tools that are not double insulated require three-prong plugs?

A) Grounded
B) Insulated
C) Lubricated
D) Shielded

Final answer:

Power tools not double insulated require three-prong plugs to be properly grounded, which is essential for safety and preventing electrical shock.

Answer:

The correct answer is A) Grounded.

Power tools that are not double insulated must have three-prong plugs to ensure that the tool is properly grounded. The three-wire system, which includes an earth/ground wire in addition to the live/hot and neutral wires, helps prevent electrical shock in the event of insulation failure or other fault conditions.

The earth/ground connection provides a low-resistance path directly to ground, which is essential for the safety of three-prong plug appliances. If the live/hot wire, which may be color-coded in various ways around the world, touches the case due to worn insulation, the presence of an earth/ground wire allows the circuit breaker to trip, interrupting the current and signaling that repair of the appliance is necessary.