Electrical Device & Outlet Boxes

Every switch, outlet, and light fixture mounts in a box that holds the device and contains its connections. Which box you grab depends first on the wall: a new-work box nails to a stud before drywall, while an old-work box clamps to finished drywall in a remodel. From there it's shape, gang count, and material. Lumera Electric carries device, outlet, and ceiling boxes in metal and nonmetallic, for new construction and remodels.

Electrical Device & Outlet Boxes

What's the difference between a new-work and old-work box?

It comes down to whether the wall is open. A new-work box mounts to a stud or joist before the drywall goes up, using a nail-on or bracket attachment. An old-work (remodel) box clamps directly to finished drywall with wings or ears that grip the back. Use new-work for framing, old-work for cut-ins.

Which box shape do I need — round, square, or gang?

Round and octagon boxes are for ceilings — they carry light fixtures and fan-rated loads. A 4-square (two-gang) box handles multiple devices or acts as a junction. Single- and multi-gang device boxes hold switches and receptacles, sized 1-gang through 4-gang. A handy (utility) box surface-mounts on exposed walls and masonry.

Do I need a fan-rated box for a ceiling fan?

Yes, and it's required by code. A standard light-fixture box can't support a fan's weight or motion and will work loose. A fan-rated box is listed to hold 35 to 70 pounds and braces between joists or screws to structure. The NEC mandates a box listed for ceiling-fan support under any paddle fan.

Metal or plastic — which electrical box should I use?

Both are code-compliant; the wiring method decides. Metal boxes are required with metal conduit or armored cable, which uses the box for grounding. Nonmetallic (PVC or fiberglass) boxes pair with NM (Romex) cable and need no bonding. Metal also resists impact for exposed or commercial work; plastic is cheaper for residential rough-in.

How many wires can go in an electrical box?

The NEC counts everything in the box, not just wires. Under NEC 314.16, each conductor, the device, the clamps, and the grounds each count as a set volume, and the total can't exceed the box's cubic-inch rating stamped inside. A crowded box overheats — size up when in doubt.

Finishing the install? Cover the device with Wall Plates, step up to a larger enclosure or pull point in Junction Boxes & Enclosures, and see covers, rings, and every other box type under Electrical Boxes & Covers.