A single receptacle installed on a 20-ampere 120-volt circuit shall have an ampere rating of what?

A single receptacle installed on a 20-ampere 120-volt circuit must have an ampere rating of 20. This is consistent with the National Electrical Code (NEC) requirements that dictate the ratings of receptacles according to the circuit they are part of. When a circuit is rated for a specific amperage, any receptacle connected to that circuit should be rated at least equal to the circuit's amperage to ensure safe operation.

Choosing a receptacle with a rating lower than the circuit's amperage could lead to overheating and potential fire hazards since the receptacle may not handle the maximum current that the circuit can supply. A 20-amp rated receptacle ensures that the device plugged into it can draw the rated power safely without risking damage or safety issues.

While other amperage ratings may be applicable in different contexts or for specific equipment, they do not meet the requirement for this particular circuit setup. Thus, the correct receptacle rating aligns with the circuit's rating, ensuring compliance with safety standards.