The throw in ofelectrical boxto use is chiefly based on the weight of the ceilinglight fixture.
Tip
Important:Theelectrical boxmust be specified as “old work.”
Old work means that the ceiling drywall is already installed.
The Spruce / Kevin Norris
A new work or new-construction box is only for ceilings that don’t yet have drywall.
Weightier ceiling lights tend to be larger or they use heavy materials like glass for the dome or diffuser.
Heavy fixtures may have extras like on-board battery backup units.
Safety Considerations
Turn off powerto all wires that run through the ceiling.
Shut off the power at theelectric service panel.
Wear a dust mask whencutting the drywallor working within the ceiling.
Drywall dust is an irritant.
Ceilings can contain fiberglass, rodent feces,black mold, and other debris that produce harmful dust.
An old work electrical box is supported by the ceiling drywall alone.
Adjustable mounting ears grab the ceiling drywall from the back to hold it in place.
Mark the joists on both sides of the installation area with a few tabs of painter’s tape.
Measure to the Installation Spot
Measure between neighboring joists with the measuring tape.
Determine the center spot by halving the number.
Mark the center spot with the pencil.
An old work plastic box doesn’t always need to be at the center of two joists.
Or, manually cut the hole with a drywall jab saw.
reset the Ceiling Hole
Clear inside the ceiling hole by hand, removing insulation and other debris.
With the utility knife, cut away ragged edges produced by cutting the hole.
Insert the Wires in the Box
Use fish tapeto pull the electric cable to the installation spot.
Insert theelectric cableinto the back of the old work plastic electrical box.
Continue to press upward with your free hand until all attachment ears are firmly in place.
This box is supported by a brace that tightens between adjacent ceiling joists.
Mark with tabs of painter’s tape.
Divide that number by two to find the middle.
With the pencil, mark this middle spot on the ceiling.
Use the hole saw or manual jab saw to cut a 4-inch-diameter hole in the ceiling.
erase the Installation Section
Reach into the ceiling and clear all debris in the installation section.
The installation section is a 5-inch-wide strip on top of the drywall running perpendicular to the adjacent joists.
The sides of the joists should be free of obstructions.
Place the brace in the hole.
Orient the brace so that it runs perpendicular to the joists and centered over the hole.
The legs must rest on the top of the ceiling drywall since they act as vertical spacers.
Tighten the Brace
Lengthen the bar by hand to tighten it between the joists.
Finish tightening with a Crescent or hex wrench if necessary.
First fish electrical cable through the ceiling to the ceiling light installation area.
For assistance with this part, call an electrician.
Attach the Box to the Brace
Slide the bracket over the top of the brace.
Center the bracket over the hole.
Carefully fit the electrical box onto the bracket’s protruding machine screws.
Add the nuts to the screws and tighten them with the pliers.
The mounting straps are included with the ceiling light kit.
Generally, colors should match or as directed by the fixture’s instructions.
Screw the ceiling light base to the mounting strap.
The box is supported by the ceiling drywall alone.
The weight limit for this throw in of box is generally six pounds or less.
You hang a heavy ceiling light with an old work metal old work box and attached brace.
The electrical box and light are supported entirely by the brace and joists, not by the ceiling drywall.
Plastic old work electrical boxes that mount directly to the ceiling drywall generally have a 6-pound limit.
210.70 Lighting Outlets Required.
A Guide to Respirators Used for Dust in Construction.Centers for Disease Control and Prevention.
