Section 334.30. Securing and Supporting. Nonmetallic-sheathed cable must be supported and secured by insulated (or, in a single-family dwelling, even by non-insulated) staples, cable ties, straps, hangers, or similar fittings, designed and installed so as not to damage the cable, at intervals not exceeding 4½ feet (1.4m) and within 12 inches (300 mm) of every outlet box, junction box, cabinet, or fitting. Flat cables may not be stapled on edge. Sections of cable protected from physical damage by a raceway need not be secured within the raceway.
