For the installation of boxes and enclosures in electrical systems, which article is primary?

• A. Article 314: Boxes, enclosures, and fittings used in electrical installations.
• B. Article 410: Luminaires and lighting equipment.
• C. Article 320: Armored Cable (AC) usage and installation.
• D. Article 250: Grounding and bonding to establish a safe path to earth and equalize potential.

Answer: (A)

The main idea being tested is which NEC article specifically governs the use and installation of boxes, enclosures, and related fittings in electrical systems. The best answer is Article 314, which is dedicated to boxes, enclosures, and fittings used in electrical installations. It sets the rules for the types of boxes and enclosures, how they are installed, how they’re mounted and supported, when they must remain accessible, and crucial details like box fill (ensuring enough internal volume for conductors and devices), clamps, covers, and other fittings. This article is the reference point for safely housing splices, terminations, and devices and for ensuring protective containment of conductors throughout the system.

Luminaires and lighting equipment are covered by Article 410, which focuses on lighting fixtures and their specific wiring and installation requirements, not on general enclosure rules. Armored Cable usage and installation is in Article 320, which deals with that particular type of cable and its handling, not the enclosures themselves. Grounding and bonding requirements are addressed in Article 250, which concerns establishing safe paths to earth and equalizing potentials, rather than enclosure design or placement.

So when you’re installing boxes and enclosures, Article 314 is the primary reference because it governs the fundamental aspects of containment, accessibility, and capacity for the electrical splices and terminations inside those enclosures.