Which statement best describes the difference between straight blade and locking receptacles?

• A. Straight blade receptacles require a locking mechanism.
• B. Locking receptacles use a locking mechanism to secure the plug.
• C. Both types require identical mounting provisions.
• D. Locking receptacles are never used in residential wiring.

Answer: (B)

The main idea here is how the plug is held in place by the receptacle. Straight blade receptacles rely on a simple fit with flat blades, so the connection can be easily pulled apart if pulled or bumped—no locking mechanism is involved. Locking receptacles include a locking mechanism that physically secures the plug when it’s inserted, typically engaging with features on the plug to twist or lock it in place. This makes the connection much more resistant to accidental disconnection in environments with movement or vibration.

That’s why the statement describing locking receptacles as using a locking mechanism to secure the plug is the best fit. It’s not accurate to say straight blade outlets require a locking mechanism, nor that both types have identical mounting provisions, and it isn’t correct to claim locking receptacles are never used in residential wiring—the latter can occur in specific residential applications or scenarios, even if it’s more common in other settings.