RVMATE Pre-Drilling 50 Amp Generator Inlet Box RVMATE, NEMA SS2-50P Power Inlet Box, 125/250V, 6250/12500W 50a Power Inlet Box, ETL Listed, Waterproof for Outdoor Use

Why I chose the RVMATE 50A inlet box

I needed a weatherproof, 50-amp inlet to feed a transfer solution from a generator without fighting cramped wiring space, questionable listings, or knockouts that require a hammer and prayer. The RVMATE 50A inlet box checked the right boxes on paper: ETL/cETL listing, a steel powder‑coated enclosure for outdoor use, pre-drilled entries, an LED confirmation light, and a removable front panel for easier wiring. After installing and using it for a series of generator tests, I’m confident saying it’s a well-thought-out box that prioritizes practicality and safety, with only a few quirks worth noting.

Build quality and weather resistance

The enclosure feels sturdy in hand—thicker steel than the bargain-basement options, with clean seams and a consistent powder coat that resists scuffs and corrosion. The hinged flip cover closes positively and sits flush; when latched, it shields the SS2‑50 inlet face well. It’s clearly designed for outdoor exposure, and after rain and hose testing, the interior stayed dry. There’s no flashy styling, just functional, tidy metalwork that inspires confidence.

One small design choice: the inlet faces forward (as most inlet boxes do), not down. A bottom-facing inlet can be a bit more naturally sheltered, but the flip cover does a good job, and with a cord set that uses a locking collar, the connection feels secure and protected. I’d still mount it under an eave or add a drip loop if you expect constant driving rain.

Thoughtful installation design

The standout feature is the pre-drilled convenience. There’s no fiddling with knockouts—RVMATE gives you clean, usable conduit entries that accept standard fittings (I used 3/4-inch EMT with compression connectors) and a removable front panel that makes terminations far less awkward. Being able to take the front off to access the wiring cavity is a big time-saver, and it prevents the “wrenching-in-a-shoebox” experience I’ve had with other inlet boxes.

Space is generous by inlet-box standards. The manufacturer claims roughly 50% more internal room, and while I didn’t break out calipers, I did route four #6 THHN/THWN-2 copper conductors and was able to dress them with reasonable bend radii. It’s still #6, so plan your approach: pre-shape the conductors, bring in neutral and ground first, keep the hot legs long until final trim, and use a torque screwdriver for the terminals. I’ve squeezed similar wiring into smaller boxes and left with bruised knuckles; here, I had room to work cleanly.

Mounting is straightforward. The back panel has solid points that accept lag screws or anchors depending on your surface. On brick or uneven siding, I recommend a flat backer block or stand-offs to keep the enclosure square so the door aligns and seals nicely. Once it’s level and plumb, everything else falls into place.

Electrical details and performance

This box uses the common NEMA SS2‑50 configuration: a 4‑wire, 125/250V, 50A service suitable for 12.5 kW class generators. I wired it to a transfer solution via 3/4-inch EMT and landed the conductors on the inlet’s lugs with proper torque. The terminals gripped firmly and showed no hot spots during sustained load tests around 9–10 kW (electric range cycling plus well pump and a few other loads). The inlet engagement feels robust, and with a cord that has a threaded locking ring, the connection tightens onto the collar of the inlet and doesn’t budge.

The green LED indicator on the flip cover lights when the inlet is energized. I found it handy during testing at dusk—confirmation at a glance that the generator output was live before throwing the transfer equipment. It’s not a substitute for a meter and doesn’t “understand” your transfer mechanism; it simply tells you there’s voltage at the inlet. If it’s lit without a generator connected, you’ve got a backfeed problem that needs immediate attention. Used as a quick sanity check in low light, it’s appreciated.

Safety and code considerations

The ETL/cETL listing matters. You want a box that’s been evaluated by a nationally recognized testing lab, and this one has. The enclosure is designed for outdoor installation, but always check local code for mounting height, bonding/grounding rules, and conductor sizing. If you’re feeding a main panel, use a proper transfer switch or listed interlock kit—no exceptions. The generator’s neutral-bonding configuration also affects how you handle neutral/ground relationships in the transfer equipment; consult the generator manual and your local authority if you’re unsure.

Other practical safety notes:
- Use THWN-2 conductors sized for your run and protection.
- Torque all terminals to spec.
- Protect the run in approved conduit and support it per code.
- Test under load and feel for heat at the inlet collar and terminals after 30–60 minutes.

Real-world use

Once installed, the RVMATE 50A inlet box becomes blissfully boring, which is exactly what I want from an electrical box. It sits outside, takes a cord, and works. The latch feels positive even with gloved hands, and the door articulates without binding. With the cord attached, the cover flips up above the plug; the LED is still visible, though less prominent than with the cover closed. The interior has enough room that if you ever have to re-land a conductor, you won’t dread opening it up.

The powder coat has held up with no rust or chalking so far, and the hardware hasn’t loosened. I pulled and reinserted the cord several times to test wear, and the inlet shows no sign of slop in the contacts.

What I’d change

• Inlet orientation: A bottom-facing inlet would offer a naturally sheltered entry and less water exposure during a storm with the cord connected. The current design is still solid, especially with a locking collar, but a downward entry would be a nice upgrade.
• LED placement and behavior: The LED is helpful, though it’s partly obscured when the cord is attached. It’s still usable, but if I were nitpicking, a small external window or side indicator would improve visibility.
• Conduit flexibility: The pre-drilled entries are great, but a couple more options (for example, a dedicated back entry) would make layout on tight exterior walls easier.

None of these are deal breakers; they’re refinements that would push an already good design toward excellent.

Who it’s for

• Homeowners setting up a 50A generator connection to a transfer switch or interlock who want a listed, outdoor-rated box that isn’t a pain to wire.
• Installers who value pre-drilled entries and removable fronts to speed up the job without sacrificing neatness.
• Anyone needing a robust SS2-50 inlet with space for #6 conductors and a weather-resistant enclosure.

If you’re only running a 30A generator, this is overkill—choose a 30A inlet instead. If you’re in a coastal or highly corrosive environment, the powder coat here is solid, but stainless hardware and regular inspection would still be wise.

The bottom line

The RVMATE 50A inlet box gets the fundamentals right: it’s listed, weather-resistant, and thoughtfully designed for installation. The removable front and pre-drilled entries save time and frustration, the interior offers real working room for #6 conductors, and the inlet itself locks up securely with a proper SS2‑50 cord. The LED indicator is a small but useful touch for quick verification.

I recommend the RVMATE 50A inlet box. It’s a straightforward, reliable piece of hardware that favors safety and ease of installation over gimmicks, and after living with it through install and load testing, I’d choose it again for a 50A generator setup.