Which of the following articles is not related to recreational facilities or equipment?

Article 605 pertains to the installation and use of power and lighting for signs and outline lighting, which is generally not specific to recreational facilities or equipment. This article focuses on the requirements for sign circuits to ensure safety and proper installation, which can be applicable to various commercial and industrial settings but does not directly address the particular themes around recreational environments.

On the other hand, Articles 551, 552, and 610 are all focused on aspects specific to recreational facilities or types of equipment commonly found in those settings, such as park trailers, outdoor amusement attractions, and the electrical systems for swimming pools and spas. Therefore, selecting Article 605 shows an understanding of which articles specifically target recreational contexts, while emphasizing the more general nature of Article 605 in other applications.