Which of the following receptacles are generally required to be listed as weather-resistant?

The reason why the choice indicating that 20A, 125V non-locking receptacles outdoors are generally required to be listed as weather-resistant is grounded in safety and code compliance. Weather-resistant receptacles are specifically designed to withstand the rigors of outdoor environments, including exposure to moisture, dirt, and temperature fluctuations. This feature is vital for ensuring safety and preventing electrical hazards, such as short circuits or electrical shocks, which can be caused by the ingress of water or debris.

In outdoor applications, electrical receptacles must be able to maintain functionality and safety standards despite the elements. Non-locking receptacles, if used outdoors, should be weather-resistant to mitigate risks associated with wet conditions. This requirement is in alignment with the National Electrical Code (NEC) guidelines that stipulate the use of weather-resistant equipment in settings where exposure to the elements is expected.

The other options refer to receptacles used indoors or are not typically exposed to environmental factors that necessitate a weather-resistant rating, thereby making them exempt from this requirement.