Short answer: export the board as a STEP file, mount it on four 10 mm M3 standoffs, keep 0.5 in [13 mm] of air around the board and above its tallest component, and land the gland at least 1 in [25 mm] from the board edge. Send the STEP with a cutout list, approve the drawing that comes back, and the custom enclosure is delivered in 10 business days from that approval. The whole job is three numbers read off the model: the outline, the tallest component, the mounting-hole pitch. Each step below, with the arithmetic worked for a 90 x 70 mm [3.5 x 2.8 in] PoE controller board.
How do I get a 3D model out of my PCB software?
Open the project's .kicad_pcb file in FreeCAD (File > Open) and export a STEP file; recent KiCAD builds also write STEP straight from the board editor's export menu. Either route gives a custom shop the file it needs.
Check the STEP in any CAD viewer before you send it: the outline, the four mounting holes and the tallest component body should all be visible. A footprint with no 3D model renders empty, and on a PoE board the RJ45 jack is usually the missing piece. Measure it with calipers and write the height on your list. Confirm the hardware revision on the model matches the board in your hand, because a respin can move the mounting holes.
Boards are one input. When the panel also holds a power supply, terminals or an HMI, the 3D models article lists what to request from each vendor so the parts stack correctly in one layout.
How much clearance does a PCB need inside an enclosure?
Keep 0.5 in [13 mm] of clear air on every side of the board and above its tallest component — enough for airflow, for live parts clear of a metal wall, and for a driver on the standoff screws.
Read the tallest part off the STEP rather than estimating. On a PoE board the RJ45 jack with its magnetics usually wins, typically 13 to 16 mm [0.5 to 0.63 in] tall, and anything against the door counts too. A wireless module adds its own rule, because the antenna wants open space or a bulkhead fitting; the PCB antenna placement article covers where it goes. Stacked add-on boards double the height, so measure the finished stack — the SBC clearance guide works that case in detail.
How do I mount the board on standoffs?
Four M3 standoffs, 10 mm [0.4 in] tall, into self-clinching nuts pressed into the backplate, hold a small board rigid; small boards carry 3.2 mm holes, so M3 is the standard fit.
The self-clinching nut mounting guide gives the hole sizes and the press-in technique for the backplate. Standoffs come 5 to 15 mm [0.2 to 0.6 in] tall, and 10 mm is the working default because wire can pass under the board edge. Put the board on the door only when it is light — under about 150 g [5 oz] — and carries one or two cables; every door swing works the wiring, so heavier or busier boards belong on the backplate.
Where does the cable gland go on a PoE board?
At least 1 in [25 mm] of cable between the jack and the gland: structured-cabling practice sets an ethernet cable's minimum bend radius at four times its outside diameter, and 6 mm [0.24 in] Cat6 needs 24 mm of it.
Set the gland centre that far below the jack so the cable arrives straight, and size the gland to the cable: its sealing range must span the cable's outside diameter, and 5 to 6 mm [0.2 to 0.24 in] ethernet usually lands in a PG7 or M12 gland. When the RJ45 plug has to pass through unterminated, the opening grows to the plug instead — the RJ45 gland sizing article works both cases. Write the gland's mounting thread and hole diameter on the cutout list; a PG7 or M12 thread wants about a 12.5 mm [0.5 in] hole, but the number you send is the one on the gland's datasheet.
How do I size the enclosure from the board model?
For a 90 x 70 mm [3.5 x 2.8 in] board with a 16 mm [0.63 in] tallest part, the arithmetic gives 116 x 121 mm [4.6 x 4.8 in] of interior wall and 39 mm [1.5 in] of depth, using the clearances above.
| Direction | Arithmetic | Minimum interior |
|---|---|---|
| Width | 90 mm board + (2 × 13 mm) = 116 mm | 4.6 in [116 mm] |
| Height | 70 mm board + (2 × 13 mm) + 25 mm gland side = 121 mm | 4.8 in [121 mm] |
| Depth | 10 mm standoffs + 16 mm part + 13 mm air = 39 mm | 1.5 in [39 mm] |
Those are minimums for the board alone, and a custom enclosure takes any size you set, so round up. Order 6 x 6 x 4 in [150 x 150 x 100 mm] and you gain room for the gland body, the cable bend and a terminal block, and the made-to-order box absorbs the larger size without penalty. Keep the depth generous: the gland nut and the bent cable both live inside, and 4 in [100 mm] of depth clears them easily.
What do I send for a custom enclosure quote?
Four things quote the job: the board's STEP, a cutout list with each hole's diameter and position, the mounting-hole pitch, and your material and rating choice; that package is enough for a drawing to come back.
- Export the STEP and confirm the outline, the holes and the tallest component in a CAD viewer.
- Write the three numbers in one place: outline 90 x 70 mm, hole pitch 80 x 60 mm, tallest part 16 mm.
- Run the sizing arithmetic above and round up to the order size.
- Pick material and type: 304 stainless for indoor washdown and food areas, 316L where salt air or chlorides reach the panel, powder-coated steel for sheltered indoor panels; Type 12 indoors, Type 4X for hose-down, rated NEMA 4X / IP66 by the manufacturer and not UL listed.
- List every opening: the gland thread, its hole diameter and its distance from the enclosure edges, plus any antenna or service opening.
- Configure it in the enclosure builder — size, material, NEMA type, mounting and quick gland cutouts — or email the package and wait for the drawing.
Hand sketches carry the day when no model exists; the no-CAD quote path shows the minimum. Panels that gather several vendors' parts need more structure, and the custom enclosure drawing package article lists the full set, with the cutout drawing checklist covering hole positions and tolerances. When a specification asks for a listed box, the enclosure listing article explains what a UL listed enclosure is and when an inspector wants one.
When does the 10 business day delivery clock start?
On the day you approve the drawing: custom enclosures are delivered in 10 business days anywhere in the world, counted from your approval of the drawing, while catalog orders count from the order itself.
Everything before approval is drawing time, and most of that time is yours. A clean first package — the three numbers, the cutout list, the material line — moves straight to a drawing you can approve. Orders are placed and paid through the Industrial Monitor Direct checkout, which builds, ships and supports every enclosure. Once you approve, the window is fixed.
What do I check before approving the drawing?
Four lines against your STEP: the mounting-hole pitch (80 x 60 mm in the worked example), every cutout centre and diameter, the interior depth against the 39 mm stack, and the material line — 316L where salt or chlorides reach the panel.
When the box arrives, prove the layout before you wire it:
- Drop the board onto the standoffs; four holes should align with light hand pressure.
- Unplug the PoE cable first — 802.3bt puts up to 90 W at 57 V on the pair, and the jack is live whenever the switch is.
- Tighten the gland until its seal grips the cable, then pull the cable to test it.
- Close the door on a clean gasket; the seam is the seal, and the walls are the last place a box like this leaks.
The mistake that costs the rating is the hole that appears on site instead of on the drawing. A factory cutout with a sealing gland holds a Type 4X box at 4X, because the seal is engineered into the opening; a hole drilled in a mounted wall is whatever the installer makes of it. Put every opening on the approval drawing — glands, antenna, a spare for service — and it arrives cut, sealed and ready for the board.
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 |
|---|---|---|---|
| 6 × 6 × 4 in | 304 stainless | 6 x 6 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 |
| 16 × 14 × 8 in | 304 stainless | 16 x 14 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 20 × 16 × 8 in | 304 stainless | 20 x 16 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Can you quote from KiCAD project files instead of a STEP?
Yes. The .kicad_pcb file carries the outline and the hole positions, and a shop can work from it, or from a dimensioned sketch that states the outline, the hole pitch and the tallest component height. The STEP just removes the transcription step, so send whichever you have, and put those three numbers in the email as well.
Does a sealed enclosure overheat a PoE board?
Work it out: a 5 W board in a sealed 6 x 6 x 4 in [150 x 150 x 100 mm] stainless box has about 0.11 m² of surface, and at a wall transfer of 3.7 W/m²K the rise is 5 ÷ (3.7 × 0.11) ≈ 12 C. At 25 C ambient the interior sits near 37 C, inside the 40 C rating most electronics carry; at 35 C it reaches 47 C, so order a bigger box, where the same load rises about 4 C.
Which stainless grade does a washdown or coastal panel need?
304 stainless for indoor washdown and food areas; 316L where salt air, brine or cleaning chemicals reach the panel. Chloride stress-corrosion cracking starts near 60 C [140 F] for both grades, so hot service changes the gasket choice before it changes the grade. What 316L buys at room temperature is pitting resistance under chloride deposits and in gasket crevices, where 304 can pit.
Do factory cutouts keep the NEMA 4X rating?
Yes, when each opening carries a part rated for it: our boxes are rated NEMA 4X / IP66 by the manufacturer, not UL listed, and a factory gland cutout holds that rating because the seal sits at the gland. The assembly takes the rating of its weakest part, so an open vent or drain on the same door drops it to that part's rating.
