OSHA 10-Hour Construction ReviewFocus Four HazardsMedium
A worker is using a portable electric drill on a construction site. The drill's power cord has a three-prong plug, but the only available outlet is a two-hole receptacle. What is the safest and most appropriate action the worker should take?
- ACut off the grounding prong to fit the outlet.
- BLocate a properly grounded three-prong outlet or use a double-insulated tool.
- CForce the three-prong plug into the two-hole receptacle.
- DUse a three-to-two prong adapter without ensuring it's grounded.
Show answer & explanationAnswer & explanation
Correct answer: B. Locate a properly grounded three-prong outlet or use a double-insulated tool.
Cutting off the grounding prong, forcing the plug, or using an ungrounded adapter defeats the purpose of the tool's grounding system, creating a severe electrocution hazard. The safest option is to find a properly grounded outlet or use a tool designed for such situations (double-insulated).
Why the other options are wrong
- A. Cutting the grounding prong removes the safety feature, creating an electrocution risk.
- C. Forcing the plug can damage the outlet, the plug, and create an electrical hazard.
- D. Using an adapter without proper grounding also defeats the safety purpose and is dangerous.
Tool Grounding Safety
Electric tools must always be used with proper grounding or be double-insulated to prevent electrocution.
- Grounding provides a path for fault current away from the user.
- Never defeat grounding mechanisms (e.g., cutting prongs).
- Double-insulated tools offer equivalent protection without a grounding prong.
Memory trick: Grounding's your guard, don't discard the third card.