Which article covers electric signs and outline lighting?

The correct choice is Article 600, as it specifically addresses the installation and safety requirements for electric signs and outline lighting. This article provides comprehensive guidelines on various aspects related to the construction, wiring, and design of electric signs, ensuring that they comply with safety standards and regulations.

Understanding Article 600 is essential for electricians working on or around electric signs, as it encompasses important safety considerations, including electrical load calculations, spacing, and materials used for both the sign and its installation. Additionally, this article covers specifications related to the installation of transformers, circuit configurations, and the use of specific types of conductors and connectors designed for these applications.

In contrast, the other articles mentioned focus on different aspects of electrical work: Article 547 deals with agricultural buildings, Article 570 addresses storage batteries, and Article 551 covers mobile and modular homes. None of these articles pertain to electric signs and outline lighting, which is why they are not the correct answers in this context.