Section 645.5 outlines alternatives to the wiring methods required in Chapters 1 through 4 for power wiring, signal wiring and optical fiber cable that may be used in an information technology equipment (ITE) room.

Section 645.4 specifies the conditions that must be fulfilled in order to use these alternative methods.

In effect, Article 645 is permissive. That is, certain special permissions are provided, but only if certain conditions are met. Article 645 does not require that the special conditions be met, but it allows the special rules to apply only if the conditions are met.