The term "listed" in Article 110 refers to what aspect of electrical products?

The term "listed" in Article 110 refers to products that have been tested and approved by recognized testing laboratories. This designation indicates that the products meet specific safety standards and performance criteria as established by national standards. These laboratories are responsible for conducting thorough testing to ensure that the products comply with applicable codes and are safe for use in electrical installations.

Being "listed" is crucial for ensuring safety in electrical systems as it helps to mitigate risks related to electrical failures and hazards. This ensures that electrical products have been evaluated not just for their functionality but also for their ability to perform safely under normal and abnormal conditions. Compliance with these standards is vital for maintaining safety within electrical installations and is a key consideration in the National Electrical Code.

The other options do not accurately reflect the meaning of "listed" in this context. Aesthetic appeal, availability in retail, and the place of manufacture do not have relevance to the safety and compliance standards associated with electrical products as defined in the NEC.