Which of the following systems is permitted for running surface extensions from an existing outlet?

The system permitted for running surface extensions from an existing outlet includes both metallic and nonmetallic options. This flexibility is important because it allows for the use of materials suited to different installation environments and preferences.

Metallic systems offer durability and protection against physical damage, making them suitable for industrial or high-risk settings. On the other hand, nonmetallic systems are usually lighter, easier to install, and can be more cost-effective, which makes them popular in residential applications. As a result, the regulations allow for the use of both types to cater to a wide range of scenarios and user needs. This accommodating approach ensures that electricians can choose the most appropriate system based on the specific requirements of the project and the environment in which they are working.