Class 1, Class 2, and Class 3 conductors and cables installed in enclosures and cable tray:

When Class 1, Class 2 or Class 3 circuit conductors and cables are installed in auxiliary gutters, raceways, boxes, or cable trays the applicable sections must be referenced to comply with the required or recommended fill requirements.

Applicable Code sections must be referenced when using the wiring methods and techniques addressed in Chapter 3. A multitude of requirements may apply.