Copkim 4 Set 8 Pcs 4 x 2'' Electrical Junction Box with Cover 1-7/8" Deep Electrical Box Metal Outlet Box, Receptacle Exposed Work Cover, Ten 1/2'' Knockouts, Drawn Construction, Silver

Why I picked up this kit

I needed a clean, code-friendly way to add a run of duplex receptacles along an exposed garage wall and a small mechanical room. Conduit, surface-mount devices, and metal boxes were the obvious choice, so I reached for the Copkim junction box kit. It includes four drawn-steel boxes and four duplex exposed-work covers—a simple package geared toward exactly this kind of job.

Over a few weekends I installed all four boxes, mixing EMT and MC cable depending on the run. The kit turned out to be a practical, budget-friendly option with a couple of quirks worth noting.

What’s in the box

• Four galvanized-steel boxes, listed at 4 x 2 inches, 1-7/8 inch deep
• Ten 1/2-inch knockouts per box
• Four duplex exposed-work covers
• Hardware for mounting devices and covers (mine included the screws and a ground screw per box)

There are no receptacles in the package, which is fine by me—I prefer spec-grade outlets anyway. The covers are the raised, exposed-work style that mount a duplex receptacle securely over the box surface.

Build and design

The boxes are drawn galvanized steel, not welded. That’s a plus for consistency and rigidity, and it helps maintain squareness—important when you’re hanging covers and trying to keep devices plumb. The galvanized finish is even, and the knockouts snap out cleanly without deforming the sidewalls.

Capacity is rated at 21.0 cubic inches. For a single duplex with the usual pigtails, that’s generous enough for most residential and light commercial runs. The 1-7/8-inch depth also gives you some breathing room behind a back-wired receptacle or if you’re stacking wirenuts for multiple branch circuits. I had no trouble fitting two 12 AWG feeds, a device, and grounds in a single box while staying within fill requirements—just be sure to do your own conductor-fill math per code.

Ten 1/2-inch knockouts around the perimeter make these versatile for EMT, MC, or NM transitions where permitted. There are no combination 3/4-inch knockouts, so if you plan to run 3/4-inch EMT throughout, you’ll either need KO enlargers or a box that ships with combo KOs.

Installation experience

I mounted two boxes directly to studs and two onto Unistrut. The drawn construction kept things square, and the cover holes aligned accurately with my devices. Screws threaded smoothly into the device ears and cover plates, and the ground screw seats solidly.

A few practical notes from the installs:

• Edge care: The exposed-work covers arrived with noticeably sharp edges. They’re stamped steel and the perimeter had a burr. I hit each cover with a few passes of a mill file and then a quick deburr with emery cloth. It took a minute per plate and was worthwhile—especially for boxes placed where someone might brush past them.
• Handling: Wear gloves during rough-in. Galvanized edges and knockout remnants can bite. I keep a deburring tool in my pouch and ran it lightly around each KO after popping it.
• Conduit transitions: With only 1/2-inch knockouts, you’ll want the right connectors on hand—set-screw or compression for EMT, listed connectors and anti-short bushings for MC. If you absolutely need a 3/4-inch entry, plan to use KO adapters or pick a box with combo knockouts from the start.
• Fire-rated walls: The boxes are marked as suitable for two-hour fire-rated walls, which is helpful for corridor or garage-to-house separations. That doesn’t eliminate the need for proper firestopping; I still used intumescent putty pads where required and sealed the annular space per the listing.

With those considerations handled, the rest is routine: bond the box, make your pigtails, mount the duplex, and cap it with the raised cover. Everything sat flush and squared up neatly.

Day-to-day use

These are exposed-work components, so the finished look is utilitarian and honest—perfect for garages, shops, and mechanical rooms. The raised covers provide good cord clearance, and the steel boxes shrug off bumps from lumber or lawn equipment. I haven’t seen any finish flaking or corrosion under normal indoor conditions.

One small detail I appreciated: the boxes didn’t warp or oil-can when I torqued connectors or ran conduit—something that can happen with thinner stock. The covers also have enough rigidity that they don’t dish when you snug the screws properly, which helps keep the receptacle face parallel to the wall.

Capacity and code considerations

At 21.0 cubic inches, there’s room for a typical duplex and a reasonable number of splices. If you’re running multiple circuits through a single box or using larger-gauge conductors, do a quick fill calculation before you commit. Device yokes, grounds, and internal clamps (these boxes don’t have internal clamps) all factor into the math. In my applications—one feed, one onward, a pigtail set, and grounds—the volume was adequate without crowding.

Bonding was straightforward with the included ground screw. If you’re using metal conduit, ensure continuity through your fittings, and use listed connectors throughout.

Where this kit makes sense

• Garage, basement, and shop circuits where exposed mounting is appropriate
• Light commercial spaces with surface raceway or EMT
• Retrofit work where you’re adding receptacles to CMU or framed walls without opening drywall
• Any installation needing boxes marked for two-hour fire-rated assemblies (while still following the full penetrations protocol)

The four-pack is especially convenient for small projects or clustered outlets around workbenches and equipment.

Limitations and quirks

• Cover plate edges are sharp out of the box. Plan to deburr them. In high-traffic areas where people might brush against the boxes, consider swapping to a different raised cover with rolled edges.
• Knockouts are 1/2-inch only. If your design standard is 3/4-inch EMT or you need combo KOs, pick a different box or be ready with KO enlargers.
• No receptacles included. Not a negative for me, but factor it into your shopping list.
• The product literature lists a 1-7/8-inch depth but a 21.0 cubic-inch capacity. Regardless, the real-world space felt comfortably generous for a single duplex and standard splices.

Value

As a package, this kit hits a nice balance: solid boxes, functional raised covers, and included hardware at a reasonable cost-per-opening. For small jobs, it’s more efficient than piecing together boxes and covers individually. If you already stock your preferred device covers or need combination knockouts, you may be better served buying components a la carte.

Tips for a cleaner install

• Deburr all edges and KOs before wiring; it protects insulation and your hands.
• Preassemble pigtails and label circuits—it keeps the box interior tidy and speeds troubleshooting later.
• Keep cover screws with the covers; a bit of blue tape works to pair them during rough-in so they don’t wander off.
• If mounting at hip height or along walkways, round over cover edges or choose rolled-edge covers.

Recommendation

I recommend the Copkim junction box kit for garages, shops, and light commercial spaces where exposed-work receptacles make sense. The drawn galvanized boxes are sturdy, the capacity is adequate for typical duplex wiring, and the included raised covers and hardware make it a straightforward, good-value bundle. The sharp cover edges are the only meaningful blemish; they’re easy enough to tame with a file, but it’s something to plan for—especially in high-traffic areas. If you need combination knockouts or a different cover profile, look elsewhere; otherwise, this kit is a dependable, budget-friendly choice that installs cleanly and holds up well in everyday use.