How To Install A Light Fixture Box In A Wall. Drill 1 inch holes down through the wall s top plate the top horizontal two by four accessible from the attic or from the attic crawlspace. If the drywall or plaster is damaged cut a larger hole and install a box that attaches directly to a stud or joist. Before cutting a hole use a stud finder to make sure no joist or stud is in the way.
Twist and connect wires. Place the back of the box on the wall or ceiling and adjust it straight and level. Then pick a rectangular or round remodeling box that is small enough to be covered by the light fixture canopy. You may need to fine tune the depth of the mounting post by screwing it in or out.
Attach the fixture.
You ll need enough cable to reach from the switch to the box plus about 3 ft. If the drywall or plaster is damaged cut a larger hole and install a box that attaches directly to a stud or joist. Match the cable either 14 2 or 12 2 to the existing wire gauge. Drill one hole through the top plate into the wall space. Prepare to hang the new fixture to connect the light fixture to the junction box screw in the crossbar the nipple lock nut and the screw collar loop that supports the fixture.