MIARALA Black Open Splice Junction Box (Single), Electrical Splice Box Wire Junction Box with Cover V0 Flame Retardant Rating

Why I reached for this junction box

I ran into the classic retrofit problem: I needed to add a new light off an existing cable run, but I didn’t want to cut everything apart, pull in new cable, and rebuild a traditional junction box with clamps and knockouts. I grabbed the MIARALA junction box because it’s designed for exactly that scenario—enclosing an existing open splice without disconnecting the conductors. You open the housing like a book, nest the connectors and cables into the slots, close it, and lock it with screws. In practice, that workflow saves real time and avoids disturbing splices that are already sound.

What it is—and what it isn’t

This is an “open splice” enclosure built from PC/ABS that meets UL514C and carries a UL94 V-0 flame rating. It’s not a weatherproof box, and it’s not a steel box with knockouts and clamps. It’s a specialized enclosure for finished or hard-to-reach locations (attics, basements, cabinets, crawl spaces) where a compliant cover for a splice is needed and you want to avoid cutting and re-terminating wires. Think of it as a compact, reusable shell that closes around an existing connection.

The housing has six cable slots, a hinged lid (rated for 50,000 cycles), retaining clips, and a simple two-screw closure. The openings accept cables up to 0.4 inches in diameter, which is an important limit if you work with heavier cable or sheathing.

Build quality and materials

The PC/ABS shell is light and quite rigid. The flame-retardant rating (UL94 V-0) is reassuring; the material self-extinguishes quickly if exposed to flame. The hinge feels precise, with consistent friction and no binding across multiple open/close cycles. The screws bite cleanly and seat flush, and the retaining clips do a good job of keeping the lid aligned while you set screws.

A couple of nuances from hands-on use:
- The plastic is stiff rather than rubbery. That’s great for dimensional stability, but it can be less forgiving if you torque the screws too hard, especially in cold conditions. I recommend a hand driver and a light touch.
- Edge finishing is tidy—no sharp flashing—and cable slots are consistent, which helps the lid close without pinching insulation.

The box includes prominent anti-shock warnings, which are easy to read and, frankly, a good reminder to leave the cover alone unless the circuit is de-energized.

Installation experience

The value proposition is in the workflow. Here’s how my process looked on a recent attic job adding a new fixture:

1. Power off and verify with a tester.
2. Confirm the existing splice is sound and connectors are appropriate (I used lever connectors for the branch and neutral splits).
3. Pre-fit the cables into the slots with the lid open. The six channels give you flexibility in how you route in/out runs and a new branch.
4. Orient the connectors so the lid closes without pressing directly on a lever or a wirenut head.
5. Close the lid, let the retaining clips engage, then drive the screws by hand until snug.
6. Label the circuit and secure the box and cables so nothing can tug on the splice.

The “no-disconnect” aspect is real: I didn’t have to untwist wirenuts or flip open and re-terminate lever connectors. That’s both a time-saver and a way to avoid reworking conductors that have already been trimmed short.

Capacity and compatibility

The six slot design comfortably handled a through-run with a branch off (line in, line out, branch; neutral in, neutral out, branch). I used compact lever connectors, which fit easily. Traditional wirenuts also fit, but bulky wirenuts on multiple conductors can crowd the lid if you don’t plan the layout.

The 0.4-inch maximum cable diameter is the governing constraint. If you’re working with flat NM-B, think in terms of the thicker dimension at the entry; measure before you assume it’ll fit. For larger or armored cables, this isn’t the right enclosure.

Safety and code context

• Listing and materials: The box is built to UL514C and uses a UL94 V-0 material. That’s appropriate for an electrical enclosure of this type.
• Accessibility: As with any junction, it must remain accessible—don’t bury it behind drywall or insulation you can’t remove without tools.
• Cable restraint: The slots provide a snug path, but they are not the same as screw-down cable clamps in a traditional metallic box. In practice, I always secure the incoming and outgoing cables with staples or straps within the vicinity of the box so the splice isn’t bearing strain.
• Wet/damp locations: There’s no gasket or IP rating. I use it only in dry locations.
• Box volume: Open splice boxes don’t expose a cubic-inch volume figure the way standard boxes do. If your jurisdiction is strict about conductor fill calculations for every enclosure, check your local AHJ. The product labeling and UL category are often sufficient, but local rules vary.

If you’re unsure about acceptance in your area, a quick call to the inspector before you start will save time later.

Durability and reuse

The hinge is overbuilt compared to most utility junction boxes, and the repeated open/close rating is impressive. I’ve opened and closed it multiple times during test fits with no sign of fatigue or misalignment. The rigid shell, however, does mean you should avoid overtightening in cold environments. Treat it like a precision plastic enclosure, not a steel can—snug is enough.

Because you aren’t cutting new threads or deforming metal knockouts each time, it’s genuinely reusable. That’s handy during troubleshooting or remodels where you might revisit a splice more than once.

Where it shines—and where it doesn’t

Best use cases:
- Retrofitting a new branch from an existing run without re-terminating conductors
- Cleaning up open splices discovered in attics, basements, or crawl spaces
- Situations where you want to protect an existing splice quickly and neatly
- Temporary or service scenarios where repeated access is likely

Limitations:
- Not suitable for wet or damp locations
- Cable diameter limit of 0.4 inches narrows applicability for larger circuits
- Less impact-resistant than a steel box; avoid high-traffic or exposed areas where it might be bumped
- No traditional clamp hardware; external strain relief is a best practice

Tips from the field

• Pre-plan connector orientation. Lever connectors lying flat under the lid close more cleanly than standing upright.
• Measure your cable. If you’re close to the 0.4-inch limit, test-fit before you commit.
• Use a hand screwdriver. A compact driver gives better feel and prevents cracking.
• Secure cables nearby. Staples or straps within a foot on each side keep the splice stress-free.
• Label the enclosure. Future-you (or the next tech) will appreciate circuit and branch notes.

The alternative: a traditional box

Could you do the same job with a standard metal or plastic junction box? Absolutely—remove the old splice, pull the cables through knockouts, clamp, re-splice, cover. That’s tried-and-true and still my approach when I’m already opening walls or need robust clamping and larger cable accommodation. The MIARALA junction box earns its place when time, accessibility, and minimal disturbance matter. It’s also a practical upgrade path when you encounter an “in the wild” open splice that needs to be enclosed immediately and cleanly.

Verdict and recommendation

The MIARALA junction box does exactly what it promises: it encloses existing splices quickly, cleanly, and safely, without forcing you to undo good terminations. The materials are appropriate for the task, the hinge and closure are reliable, and the internal layout handles common residential branching with compact connectors. You trade away some ruggedness compared to steel, and you need to respect the 0.4-inch cable limit and dry-location use. Within those constraints, it’s a genuine time-saver.

I recommend this tool for electricians and capable DIYers who regularly tackle retrofits, service calls, and cleanup of legacy open splices. It’s not a one-box-for-everything solution, but as a specialized enclosure for dry locations, it’s effective, code-conscious when used properly, and efficient. If your work involves adding branches in attics or basements—or you value not disturbing existing splices—this belongs in the kit.