How to Run Romex in an Unfinished Basement

Run Cable on the Sides of Studs and Joists

• One of the easiest ways to run nonmetallic sheathed cable in an unfinished basement is to run it along the sides or faces of the wall studs and joists (the framing members of the floor above, which form the basement ceiling). When running cable along the sides of wall studs and joists, it must be set back at least 1 1/4 inches from the nearest edge of the stud or joist. This setback is a National Electrical Code, or NEC, requirement to protect the cable from possible damage by nails or screws when drywall or other finish is installed. This minimal setback is also a requirement of all local electrical codes. Nonmetallic sheathed cable installed on the faces of studs and joists must also be supported at intervals not exceeding 4 1/2 feet, with cable staples or some other approved means. Nonmetallic sheathed cable must also be supported within 12 inches of any electrical device or box it enters or exits.

Running Cable Through Drilled Holes

• Nonmetallic sheathed cable can be run perpendicular to wall studs and floor joists by running it through holes drilled through the framing members. As required by the NEC, holes must provide for a minimum 1 1/4-inch setback from the edges of any framing members, to protect the cable from damage by nails or screws. In addition, building codes prescribe strict requirements for drilling into joists and load-bearing studs. For example, holes in joists must be at least 2 inches from any edge or other holes or notches, and no holes are allowed in the middle 1/3 of the joist's span. Follow the local building code when making any alterations to studs or joists.

Running Cable in Notches

• Another way of installing cable perpendicular to studs or joists is by laying it in notches cut in the front edges of the studs or joists. When installing cable in this manner, the NEC requires that the notches be covered with steel nailing plates to protect the cable against damage from screws or nails. Steel nailing plates must also be used when cable is run through holes if the minimal 1 1/4-inch setback cannot be maintained. As with holes, notches in joists and load-bearing studs are strictly governed by the local building code, so be sure to follow all requirements. Improper alterations of these framing members can lead to structural failure.

Junction Boxes

• Junction boxes, electrical device boxes or outlet boxes may be used in the running of cable in an unfinished basement or other unfinished space. When used, they must be installed so they will not become concealed if wall and ceiling finishes are later installed. The NEC requires that all electrical boxes be accessible without the removal of any permanent structural feature, such as wall paneling or ceiling tiles.