Which of the following is typically required for outdoor wiring installations?

For outdoor wiring installations, the use of weather-resistant connectors is essential. These connectors are designed specifically to withstand the elements, including moisture, UV exposure, and temperature fluctuations, which are common in outdoor environments. They ensure a secure connection and prevent water ingress, which could potentially lead to short circuits, corrosion, and electrical hazards.

In contrast, while standard plastic conduit, non-metallic sheathed cable, and underground feeder cable may be used in specific situations, they do not inherently offer the same level of protection against environmental factors as weather-resistant connectors. These other options provide structural protection or are suitable for certain types of installations, but they do not directly address the need for reliable, moisture-proof connectivity in outdoor settings like weather-resistant connectors do.