A 304 or 316L stainless wall-mount enclosure, clamped to the pole with U-bolts through its mounting feet, is the right choice for an outdoor SBC or radio next to an antenna. A 10 x 8 x 4 in box suits most single-board computers with a small power supply. The two things that decide success are how it grips the pole and where the cables enter.
Why stainless instead of a plastic box
Zip-tied plastic cases work until the sun embrittles the plastic and the ties creep, which takes a season or two. A metal box on U-bolts does not move, does not UV-degrade, and gives the antenna a solid, grounded mass beside it. Stainless also carries a manufacturer rating of NEMA 4X / IP66; not UL listed, so hose-down rain and dust are covered without paint to chip.
The trade-off is weight and cost, both modest at the small sizes a board needs. If your question is really about ingress protection itself rather than mounting, the comparison of NEMA 4X with IP66 covers how the two codes relate.
What the environment asks of the box
A pole is the harshest mounting point on a site. Rain driven by wind hits the box from every direction, including upward as it runs down the pole. Sun heats the box above air temperature, often 20 to 30 F (11 to 17 C) more on a dark or shaded-free face. Dust, insects and spiders find the smallest gap.
For coastal or salted-road sites, pick 316L; the molybdenum in it resists chloride pitting that eats 304 near the sea. For inland sites on fresh poles, 304 is fine and cheaper. If rust has already bitten an existing installation, the article on why a stainless enclosure rusts explains the usual causes.
Sizing the box around the board
Work from the parts, not from guesses:
| Part | Typical space needed |
|---|---|
| SBC or radio board on stand-offs | the board footprint, plus 1 in (25 mm) around it for connectors |
| DIN-rail power supply or PoE injector | 2-4 in (50-100 mm) of rail width |
| Cable slack and bending room at glands | 2-3 in (50-75 mm) of depth |
| Spare for changes | about 25% of total volume |
An 8 x 6 x 4 in 304 wall-mount enclosure holds a single board and a small supply with little slack. For a board, PoE injector and room to work, a 10 x 8 x 4 in 304 wall-mount enclosure is the usual choice. Deeper 6 in boxes such as the 12 x 10 x 6 in 304 wall-mount enclosure suit a DIN-rail layout with terminals. The same three sizes exist in 316L and as a 10 x 8 x 4 in 316L enclosure for chloride-heavy air.
The sizing guide for small enclosures walks through the volume math in more detail than a spec table can.
Mounting it to the pole
Stainless wall-mount boxes come with mounting feet, and those feet are the U-bolt landing. Two stainless U-bolts sized to the pole, one near the top of the box and one near the bottom, hold it against rotation and wind. For a 2 in (50 mm) pole, a 5/16 in (8 mm) U-bolt is typical; torque to the clamp maker's value, not to feel.
Three rules keep the rating intact:
- Bolt through the feet or a back plate, never straight through the box wall.
- Keep the glanded face pointing down.
- Leave a hand's width between the box top and any antenna bracket so you can still reach the door latch.
The general enclosure mounting guide covers heights, hardware and working clearances. For ground mounting instead, the article on bolting a freestanding NEMA 4 enclosure to the floor is the closest reference.
Getting cables in without leaking
Every cable enters through a gland in the bottom face, sized to the cable's actual outside diameter at that point. For Ethernet, a gland made for an RJ45 connector is different from a plain cable gland; the article on cable glands for RJ45 connectors covers the sizing. Antenna coax is its own problem: the article on antenna feedthrough sealing shows how to pass a cable that must not be cut.
Drip-loop every cable below its gland so water runs off the loop, not into the box. If a gland must sit higher than the bottom of the box, the piece on glands facing up on an outdoor junction box explains the precautions. When the number of entries grows, a gland plate beats a pile of drilled holes; the article on when to specify a gland plate covers that.
Heat from the board
A sealed IP66 box cannot vent, so the board's dissipation has to leave through the walls. A single-board computer drawing 10 W in a 10 x 8 x 4 in steel box rises a modest amount above ambient in still air; 30 W and the same box gets uncomfortable in summer sun. Add the solar gain article's numbers to the ambient before you size anything.
If the math says the box will run hot, options in order of preference: a bigger box (more wall area), a thermally conductive path from the board to the wall, and last, an active cooler. The article on removing heat from a small sealed IP66 enclosure works through the calculations, and the air conditioner sizing article covers the powered end of the problem.
What to put on the order
- Grade: 304 inland, 316L coastal or industrial.
- Size from the parts list above, with the 25% spare.
- Mounting: leave the feet standard; specify any extra back-plate holes on the drawing.
- Glands: bottom face, one per cable, sized to each cable's diameter.
- Door: standard hinged gasketed door; specify a cutout only if a display lives in the box.
Every box is made to order and delivered in 10 business days, counted from your order, or from drawing approval for custom work. If the antenna side of the installation is the harder half, the article on a small outdoor enclosure for a wireless radio board stays with the board-level questions.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 8 × 6 × 4 in | 304 stainless | 8 x 6 x 4 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 10 × 8 × 4 in | 304 stainless | 10 x 8 x 4 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 12 × 10 × 6 in | 304 stainless | 12 x 10 x 6 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 8 × 6 × 4 in | 316L stainless | 8 x 6 x 4 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 10 × 8 × 4 in | 316L stainless | 10 x 8 x 4 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Can a wall-mount enclosure be mounted on a pole?
Yes. A stainless wall-mount box clamps to a pole with two U-bolts through the back wall or through mounting feet, as long as the bolts sit on bearing plates or the feet so they do not deform the enclosure. Keep the load small: a light box with a board inside is fine; a deep box full of gear is not a pole-mount job.
How do I keep rain out of a pole-mounted enclosure?
Enter cables through correctly sized glands on the bottom face, drip-loop every cable below the gland, and seal any antenna feedthrough with a proper bulkhead seal. Never drill the top of the box. The mounting holes must go through feet or a back plate, never straight through the gasketed wall.
What size enclosure fits a small SBC or radio board?
A single board computer or radio in DIN-rail or stand-off form typically fits in an 8 x 6 x 4 in or 10 x 8 x 4 in box with room for a small power supply and cable slack. Add roughly 25% spare volume for wiring, PoE injectors and future changes, and check the depth: boards plus stand-offs plus glands eat more depth than you expect.
Do I need 304 or 316L stainless for a pole-mounted box?
304 is enough for most outdoor, non-coastal sites. Choose 316L within a few miles of the coast, near roads treated with de-icing salt, or in industrial air with chlorides. Both grades are rated NEMA 4X / IP66 by the manufacturer; not UL listed, so the rating choice is about corrosion, not ingress.
