May I install romex in a 2-inch metal conduit that is 24 inches long into a panel without securing the cables within 12 inches of where they enter the panel? The general requirement for cable termination is 312.5(C). This one-sentence rule says: “Where cable is used, each cable shall be secured to the cabinet, cutout box, or meter socket enclosure.” However, there is a long exception for nonmetallic sheathed cable (romex), and it is pretty detailed.
Nonmetallic sheathed cables are permitted to enter the top of a service-mounted panelboard through a nonflexible raceway that is not less than 18 inches long or longer than 10 feet.
The romex cable must be secured within 12 inches of the outer end of the raceway; the raceway must extend directly above the panelboard and cannot penetrate the structural ceiling; a fitting is required at each end of the raceway to protect the cables from abrasion, and the fittings must remain accessible after installation; the raceway must be sealed at its outer end; the cable sheath must be continuous in the raceway and extend into the panelboard beyond the fitting for at least 1/4-inch; the raceway is secured in accordance with the requirements of the applicable article for the wiring method, and the wire fill table in Chapter 9 must be used to prevent cable overfill.
To determine the number of cables permitted in the 2-inch conduit, Note 9 to Table 1 in Chapter 9 requires that multiconductor cables be treated as a single conductor. For cables with oval or elliptical cross-sections, the cross-sectional area is based on the major diameter of the ellipse to obtain an equivalent circle diameter.
