Receptacles installed on 15- and 20-ampere branch circuits must be of which type?

Receptacles installed on 15- and 20-ampere branch circuits must be of the grounding type to ensure safety and compliance with electrical code requirements. Grounding receptacles provide a pathway for electrical current to return to the ground in case of a fault. This is crucial because it helps prevent electric shock and allows circuit breakers to trip and clear the fault, thereby reducing the risk of electrical fires.

Grounding receptacles have a third prong that connects to the ground wire, which is an essential safety feature in modern electrical systems. In contrast, ungrounded receptacles lack the grounding prong and do not provide adequate protection against faults. Non-polarized receptacles do not address the grounding requirement, as they are typically used in applications where grounding is not necessary. Double-pole receptacles are specifically designed for use with 240-volt circuits, which makes them unsuitable for standard 15- and 20-ampere branch circuits typically used for lighting and general purposes in residential settings.

By utilizing grounding receptacles, the risks associated with electrical faults are significantly mitigated, making them the correct choice for these circuits.