Which type of receptacle outlets must have approved ground-fault circuit interrupters for personnel protection?

The correct choice is based on the National Electrical Code (NEC) requirements, which mandate that certain receptacle outlets be equipped with ground-fault circuit interrupters (GFCIs) for personnel protection. Specifically, GFCIs are required for all 120-volt, single-phase 15- and 20-ampere outlets because these are commonly used in areas where the risk of electric shock is higher, such as in wet or damp locations (like bathrooms, kitchens, and outdoor installations).

The purpose of a GFCI is to enhance safety by quickly shutting off the electricity supply when it detects an imbalance in the electrical current, which could happen if someone were to come into contact with a live wire while standing on a conductive surface. This protection is particularly critical in residential and commercial settings where people are at risk of electric shock.

While other outlets play vital roles in electrical systems, the specific requirement for 120-volt, single-phase 15- and 20-ampere outlets directly correlates to the safety regulations intended to protect individuals in environments where the risk of electric shock is significant.