Short answer: for a 5-port gigabit router board of about 5.5 x 4.3 in [140 x 110 mm] drawing 8 W, order a stainless wall-mount box with 6.5 x 5.5 x 2.4 in [165 x 140 x 60 mm] of internal space. That is 1.2 in [30 mm] for the board on standoffs and its tallest connector, plus 1.2 in [30 mm] for the cable bends at the gland. The board size and the 8 W are this example's assumptions; take them from your board's drawing and the same stack-up gives your box. Below: the rating by site, the depth arithmetic, the heat check that usually pushes an always-on board to the next size, and the cutout list for the order.
Where the board lives sets the rating
The rating follows the site, not the board. A dry room on a shelf asks for Type 1, the basic indoor protection against accidental contact. A workshop with dust and dripping oil asks for Type 12. A wall that sees rain, sprinklers or hose-down needs Type 4X. The types come from NEMA 250 and the IP codes from IEC 60529; our enclosures are manufacturer-rated for the specified design, not UL listed. In US installations, NEC 110.28 states that IP ratings are not a substitute for enclosure type ratings, so put the NEMA type on the drawing when the spec calls for one.
| Where the box lives | Rating to order | Material that fits |
|---|---|---|
| Dry room, desk or shelf | Type 1 | 304 stainless or aluminum |
| Workshop dust and light drips | Type 12 | 304 stainless, #4 brushed |
| Outdoor wall, rain and hose-down | Type 4X / IP66 | 304 stainless |
| Salt air, brine or sanitizer spray | Type 4X / IP66 | 316L stainless |
Pick the material with the same map. 304 stainless carries indoor washdown and most outdoor sites; 316L earns its cost in salt air, brine and chemical areas. Polycarbonate and fiberglass bodies pass radio signals, which matters in the antenna section below.
Size the depth from the board stack
Depth comes from a stack-up, and every number in it comes off the board drawing. The example uses typical values; swap in yours:
- M3 standoff under the board: 0.25 in [6 mm]
- PCB laminate: 0.06 in [1.6 mm], the standard thickness
- tallest part above the board, the RJ45 jacks with their LEDs: about 0.55 in [14 mm]
- air over the jacks for pigtails and gasket travel: 0.3 in [8 mm]
The stack is 0.25 + 0.06 + 0.55 + 0.3 = 1.16 in, so call it 1.2 in [30 mm].
The gland side adds the bend allowance. Structured-cabling installation guides call for a minimum bend radius of 4x the cable OD: Cat5e at 0.20 in OD turns in 0.8 in, while Cat6 at 0.25-0.30 in OD turns in 1.0-1.2 in. Budget 1.2 in [30 mm] of clear depth and you cover both cables.
Total internal depth: 1.2 + 1.2 = 2.4 in [60 mm]. A Cat5e-only build clears with 2.0 in [50 mm].
Width and height take 0.4 in [10 mm] of clearance around the board on every side for gasket lips, tapped standoffs and pigtail routing: 5.5 + 0.8 = 6.3 in and 4.3 + 0.8 = 5.1 in. Order 6.5 x 5.5 in [165 x 140 mm] and everything fits with margin. Mount the board to the back wall on four M3 standoffs at its mounting-hole pattern, and keep those 0.4 in borders clear so the air can move.
Check the watts against the wall
A sealed box sheds heat only through its surface. For a stainless wall use k = 3.7 W/m²K, and the rise is ΔT = Q / (k x A).
The 6.5 x 5.5 x 2.4 in body measures about 0.165 x 0.140 x 0.061 m outside, so A = 2 x (0.165 x 0.140 + 0.140 x 0.061 + 0.165 x 0.061) = 0.083 m². With the example board's 8 W: ΔT = 8 / (3.7 x 0.083) = 26 K. A 25 C room then sits near 50 C inside, past the 40 C ambient rating most electronics carry unless their datasheet says more.
Order the next size up for an always-on board. A 10 x 8 x 4 in body gives A ≈ 0.196 m², so ΔT = 8 / (3.7 x 0.196) = 11 K, and the same room lands at 36 C. The heat, not the stack, sets that purchase.
Budget shortcut: each 0.1 m² of stainless wall clears about 3.7 W per 10 K of rise. A 15 W board nearly doubles the rise; powder-coated steel, k = 5.5 W/m²K, brings the small body's 26 K down to about 17 K. Keep the build sealed, because a louver, fan-filter or open vent sets the whole assembly's rating to that part's own rating. Outdoors, keep the box out of direct sun, since the solar load stacks on top of the 11 K.
Cable entry: glands, couplers or jack cutouts
On a Type 4X build the cables enter through the bottom wall, one gland per cable, so nothing runs downhill into a hole. Keep the 1.2 in bend allowance clear above each gland and form a drip loop outside that hangs about 2 in [50 mm] below the fitting. Face the glands down or sideways; the notes on mounting cable glands facing up cover that layout. The entry devices carry the sealing duty, so each one keeps the rating on its own body for the assembly to hold Type 4X.
Pick a gland by its seal, not its thread: the seal range must cover your cable OD, and matching the seal to the cable shows how to read it. An M20 gland suits a single Ethernet cable; the M20 hole sizes give the cutout diameter the factory punches.
If you want factory-terminated leads outside the wall, use RJ45 feed-through couplers instead. The field cable seals into the coupler's outer side and a short patch lead runs from the coupler to the board's jack; sizing and sealing an RJ45 gland covers the geometry.
On a dry indoor Type 1 build you can skip glands altogether: sit the board's jack plate against the wall and cut the opening so the jacks protrude. Only a sealed build keeps a rating in wet locations.
Send the cutouts with the order instead of drilling later. The cutouts guide covers hole types and spacing, and the cutout designer lays your holes out on the exact face and exports the drawing with the quote. A hole you cut in the field breaks the sealed wall until it is re-sealed; watertight sealing walkthrough for custom cutouts shows that job. The custom stainless cutouts page compares new openings in a standard body against a fully custom body.
Antennas through a metal wall
A stainless box is a Faraday shield: leave the antennas inside and the Wi-Fi dies at the wall. Take them out through SMA bulkheads and reach the board with short u.FL pigtails. Space the bulkheads at least half a wavelength apart; at 2.4 GHz the wavelength is 12.5 cm [4.9 in], so give them 2.5 in [63 mm]. The antenna bulkhead layout guide covers placement and sealing. If you would rather keep the antennas inside, order a polycarbonate or fiberglass body: radio passes, and the cutout list shrinks to power and Ethernet.
What to put on the order
| Line | Value for the example board |
|---|---|
| Body | Wall-mount, 6.5 x 5.5 x 2.4 in [165 x 140 x 60 mm] internal; 10 x 8 x 4 in when the 8 W board runs always-on |
| Material | 304 stainless, #4 brushed; 316L for salt air or brine |
| Rating | Type 4X / IP66 outdoors; Type 1 or Type 12 indoors |
| Cutouts | M20 holes in the bottom wall, one per cable; SMA bulkhead holes spaced 2.5 in [63 mm] |
| Mounting | Four M3 tapped standoffs, 0.25 in [6 mm] long, at the board's hole pattern |
| Glands | M20 with a seal that covers the cable OD, O-ring and locknut on the wall |
Start from custom enclosures, where you set the material, the three dimensions and every cutout from one piece. We build each box to order and deliver it in 10 business days, counted from your approval of the drawing for custom work.
Decision by case. Dry room, occasional use: the small Type 1 body at 2.0 in of depth with Cat5e, jacks at the wall if you want zero glands. Dusty workshop: the same geometry as Type 12 with bottom-entry glands. Always-on 8 W board, indoors or out: 10 x 8 x 4 in, because the heat sets that size. Outdoor wall: 304 stainless Type 4X with M20 glands in the bottom and antennas on bulkheads. Salt air or brine: the same body again, in 316L.
Catalog dimensions to compare
Compare these catalog dimensions with your component layout. Open each enclosure for its rating, material and usable space, then check those specifications against your application.
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 10 × 8 × 4 in | 304 stainless | 10 x 8 x 4 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 10 × 8 × 6 in | 304 stainless | 10 x 8 x 6 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 |
| 16 × 12 × 8 in | 304 stainless | 16 x 12 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Which gland thread fits one Ethernet cable?
An M20 gland is the usual pick for a single Cat5e or Cat6 cable. Its seals are sold in overlapping ranges around 0.20-0.31 in [5-8 mm] and 0.24-0.39 in [6-10 mm] OD, so one of the two spans either cable. The seal, not the thread, does the sealing, so the range has to cover your cable's diameter before the gland goes on the cutout list.
Can the router board mount on the door?
Yes. A bare board is light enough for four M3 standoffs, 0.25 in [6 mm] long, set at the board's mounting-hole pattern. Give the pigtail and DC leads a 1.5 in [40 mm] service loop where they cross the hinge line, so the loop flexes instead of the solder joints, and swing the door through its full 90 degrees with everything connected before you close the job out.
Should I drill a vent or a drain hole?
Neither on this build. The example board's 8 W rises about 11 K inside the 10 x 8 x 4 in stainless body, so it needs no airflow; a louver, fan or drain sets the whole assembly's rating to that part's own rating and the Type 4X rating is gone. Handle condensation with a sound gasket, bottom-entry glands and drip loops instead of a hole.
What changes when a second board or a small switch goes in?
Run the stack-up a second time and add the heights. A compact Ethernet switch about 1.1 in [28 mm] tall, sitting flat above the router board, adds its height plus a 0.4 in [10 mm] air gap, so the 2.4 in [60 mm] depth becomes about 3.9 in [100 mm]. Recheck the heat too: a powered switch can add 5 W or more to the 8 W example budget, more than doubling the small body's 26 K rise.
Is 304 or 316L the right stainless outdoors?
304 stainless covers most outdoor sites and indoor washdown. 316L is the pick for salt air, brine and sanitizer spray, because its molybdenum raises pitting and crevice resistance. Both grades share a chloride stress-corrosion threshold near 60 C (140 F), which is exactly why a hot sealed box in a chloride-heavy area is the job where 316L earns its extra cost.
