Which article details the requirements for switches?

The correct choice is Article 404, as this article specifically outlines the requirements for switches in electrical installations. It addresses various types of switches, their ratings, installation practices, and the necessary safety considerations to ensure that they function properly and safely within electrical systems.

Article 404 covers the installation guidelines for general-use switches, including toggle switches, push-button switches, and similar devices, providing the necessary details on their wiring, placement, and both mechanical and electrical design considerations to promote safe operation. This article helps ensure that switches are not only effective in controlling electrical circuits but are also installed with safety and compliance to the National Electrical Code in mind.

The other articles mentioned do not pertain directly to the requirements for switches. Article 400 relates to flexible cords and cables, Article 392 deals with cable trays, and Article 406 focuses on receptacles, cord connectors, and attachment plugs. Each of these articles is critical for their respective areas, but only Article 404 specifically addresses the installation and use of switches.