Short answer: yes — the existing camera junction box can host the new wifi access point (AP) when two tests pass. A Power over Ethernet (PoE) pass-through switch has to fit, which takes a box near 10 x 8 x 4 in [254 x 203 x 102 mm] outside, and the one uplink cable has to carry the whole chain. An IEEE 802.3at feed guarantees 25.5 W at the box, which leaves about 20 W for the camera and the AP once the switch takes its own 5 W. Budgets that add to more get an 802.3bt uplink or a second home-run cable; an 802.3af-only feed always means the second cable.
Can you add the AP to the camera box you already have?
You can reuse it when three things line up: the box holds a pass-through switch with two outgoing cable exits, the uplink port is rated IEEE 802.3at or better, and the datasheet draws of switch, camera and AP add to 25.5 W or less at the box.
The job adds one device and one gland. The switch takes the uplink in, feeds the camera on a port of its own, and gives the AP a port. The camera keeps its existing cable and its gland. The AP drop gets a new low hole with a gland of its own.
Test all three before you order anything:
- Space — the switch, its termination room and two cable exits fit without pressing the door onto the gasket.
- Power — switch plus camera plus AP draw 25.5 W or less on an 802.3at uplink, 51 W or less on an 802.3bt Type 3 uplink.
- Sealing — one clean round cutout per cable, closed by a gland matched to that cable's jacket.
The sections below run the arithmetic for each test.
How much power does the one uplink cable carry?
One IEEE 802.3at port budgets 30 W at the switch end and guarantees 25.5 W at the powered device, so once a 5 W pass-through switch takes its share, about 20.5 W is left for the camera and the AP together.
The port figure is what the indoor switch reserves for the run. The device figure is what the standard still delivers at the far end after cable loss, so budget on the device figure at any cable length:
| IEEE standard | Port budget at the powering switch | Guaranteed at the powered device |
|---|---|---|
| 802.3af (PoE) | 15.4 W | 12.95 W |
| 802.3at (PoE+) | 30 W | 25.5 W |
| 802.3bt Type 3 | 60 W | 51 W |
The budget that closes. Take an 8 W camera, a 10 W AP and a 5 W switch, all datasheet maxima: 8 + 10 + 5 = 23 W against the 25.5 W the at uplink delivers at the box. That is a 2.5 W margin, and the reuse works on the one cable. Budget maxima, not typical draws; a chain that only closes on typicals goes down on the first cold night with infrared lights and heaters running.
The one that looks fine and is not. A 13 W camera and a 12 W AP come to 25 W before the switch; with it the chain wants 30 W. That is 4.5 W more than the box receives on at. The pass-through switch then cannot give its two ports what they need, and the AP drops off or never boots. Move the uplink to 802.3bt Type 3, where 51 W at the box minus the 5 W switch leaves 46 W for the pair and a 21 W margin. Otherwise pull a second cable for the AP.
Three datasheet lines decide the rest:
- Switch input class. Small pass-through units commonly accept 802.3at input only; a bt uplink still powers them, at the at level and its smaller budget.
- Port speed. A 10/100 pass-through caps the AP's uplink at 100 Mbps; take a gigabit unit for anything modern.
- Negotiation. 802.3af/at/bt devices negotiate power; a passive injector does not, and 48 V passive into a port built for less can damage it.
PoE rides the data pairs as phantom voltage, so the RJ45 terminations stay as they are; the PoE pinout reference for 802.3af and 802.3at shows which pairs carry it.
Will the pass-through switch overheat the box?
No — the only heat that stays inside is the pass-through switch's own loss, about 5 W, and in the example stainless box that raises the interior roughly 7 °C above ambient by the sealed-wall value of 3.7 W/m²K.
The camera's and the AP's delivered power travels out through the cables, so the sealed box sheds the switch's loss and nothing else. The rise above ambient is ΔT = P ÷ (k × A), with k = 3.7 W/m²K for a stainless wall (natural convection plus radiation) and A the outside surface area.
Worked example on that box, 10 x 8 x 4 in outside: A = 2 × (10 × 8) + 2 × (10 × 4) + 2 × (8 × 4) = 160 + 80 + 64 = 304 in² = 0.196 m². The rise is ΔT = 5 W ÷ (3.7 W/m²K × 0.196 m²) = 5 ÷ 0.73 = 6.9 K, call it 7 °C.
A shaded wall at 30 °C puts the interior near 37 °C, inside the 40 °C ambient that most small Ethernet gear carries unless its datasheet allows more. Doubling the switch draw doubles the rise: a 10 W unit sits about 14 °C over ambient. Direct sun adds roughly 10 to 15 °C at the wall surface, so a west wall in summer lands the interior near 50 °C; shade the box or pick a switch datasheet that covers it.
The same wall-loss method scales to bigger loads; the PoE switch heat-load sizing walk-through runs it port by port.
How much room does the box need inside?
Plan on the example box, 10 x 8 x 4 in outside, about 306 in³ of interior volume; its nominal interior dimensions are in the table below. A pass-through switch, two gland exits and cable dress fill roughly two-thirds of that.
A gigabit pass-through unit occupies roughly 5 x 4 x 1.5 in, some 30 in³; take yours from its datasheet. The rest is working room: bend space at the uplink termination, two gland bodies on the bottom wall, and enough depth that the door closes without loading the gasket. Depth is the tight dimension: with the mounting panel in place, a 1.5 in deep switch leaves about 2 in of clearance to the door in the 3.91 in interior.
| Catalog box | Interior | Fit |
|---|---|---|
| 8 x 6 x 4 in, 304 | 7.91 x 5.91 x 3.91 in | smallest switches only |
| 10 x 8 x 4 in, 304 | 9.91 x 7.91 x 3.91 in | the example build |
| 12 x 10 x 6 in, 304 | 11.91 x 9.91 x 5.91 in | room for surge modules too |
The same interior logic sizes a box around a full-sized PoE switch; the outdoor wall-mount PoE switch sizing guide carries the clearance numbers per module.
Where does the AP go?
Outside the box — a stainless wall screens the 2.4 GHz and 5 GHz radios like a Faraday cage, so the AP mounts on the outside of the box or just above it, fed by a short cable through its own gland.
Behind a gasketed stainless wall, a phone across the yard will barely hear the radio; closed metal is a shield, not a radome. Bracket the AP to the box face or to the wall above it and keep the antennas vertical. If you paint the box to match the wall, stop at the radio's cover, because paint on the antenna detunes it.
Outside mounting also keeps the radio's heat out of the sealed interior, so the 7 °C rise stays a switch-only number. Bring the AP feed out of a bottom gland and let it loop down before it rises to the radio; water then runs off the cable instead of standing on the seal.
What does the new gland have to do?
Match the gland to the box, not the other way round: an IP66-rated gland with a clamping range that includes the Cat6 jacket — outdoor-rated cable runs about 6 to 8 mm OD — set into a clean round cutout, one cable per gland.
The weakest opening sets the assembly: a gland, vent or connector rated below the box carries the whole build down to its own number. Our wall-mount boxes are manufacturer-rated NEMA 4X / IP66 and not UL listed, and a gland below IP66 drags them to its rating. Hole sizes, thread patterns and cutout prep sit in the cutouts, glands and windows guide.
Get four details right:
- Clamping range. Measure the jacket; outdoor Cat6 runs about 6 to 8 mm OD, and the gland's seal range must include it.
- Hole size. Drill to the gland maker's hole size and deburr; a common M20-pattern gland takes a 22 mm [0.87 in] hole.
- Thread engagement. The body needs its full thread in the wall; a gland too short for the box threads bottoms out and loses the seal.
- One cable per gland. Two jackets under one seal rarely clamp both; the two-cables-one-gland exceptions are narrow.
Set every entry on the bottom wall and loop each cable down before it rises; a gland facing up collects and holds water on its seal. Adding a drop to an existing blanked cutout follows the same round-hole-and-gland routine.
Switch the uplink port off before the first cut, and measure the cable dead at the terminals before it lands.
What do you order when the existing box is too small?
Order a 10 x 8 x 4 in wall-mount box in 304 stainless for dry inland walls, 316L near salt water or chlorides, with three bottom cutouts drawn for the uplink, the camera drop and the AP feed.
| Line | What to specify |
|---|---|
| Rating | Manufacturer-rated NEMA 4X / IP66; not UL listed |
| Material | 304 stainless inland; 316L within reach of salt spray or chloride deposits |
| Size | The example size, 10 x 8 x 4 in outside |
| Cutouts | Three bottom entries, drawn to gland thread and measured cable ODs |
| Interior | Removable panel with a pad or DIN rail for the switch |
| Delivery | Delivered in 10 business days from the order; custom work counts from drawing approval |
Chlorides decide the grade: 304 pits under salty deposits even at room temperature, so coastal walls, pool decks and washdown lines take the 10 x 8 x 4 in 316L box and dry inland walls take the 304 version. The 12 x 10 x 6 in model in the table above adds room for surge protection on the uplink.
When the choice sits between sizes, the enclosure selector shortlists by rating, listing and interior, and the 304 and 316L wall-mount range runs from 6 x 4 x 4 to 60 x 36 x 16 in. A bare splice box with no panel rarely makes the cut; the outdoor camera box specification list shows what a keeper looks like. Orders build and ship through the Industrial Monitor Direct checkout, delivered in 10 business days anywhere in the world.
When does a second cable beat the pass-through switch?
Pull the second cable whenever the budget will not close on the uplink you have: draws over 25.5 W combined, an 802.3af-only feed at 12.95 W, or a 2.5 Gigabit AP that no small pass-through switch in the box can feed.
| Situation | Decision |
|---|---|
| Draws total 25.5 W or less; at uplink; gigabit switch | Reuse the box: switch inside, AP outside, one new gland |
| Draws total 26 to 51 W; switch accepts 802.3bt input | Still one cable: move the uplink to bt Type 3 |
| Feed is af only, 12.95 W at the box | Second home-run for the AP |
| AP needs 2.5 GbE or a power class the switch cannot pass | Second home-run |
| Interior short of about 200 in³ of dress room | Step up a size instead of squeezing |
The reuse succeeds on paper before it touches the wall: draws summed against 25.5 W, a 7 °C rise checked against the switch's own rating, and three glands set low with drip loops. Where the numbers close, you buy one switch and one gland; where they do not, the second cable is the only cable you pull.
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 |
| 10 × 8 × 4 in | 316L 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 |
Questions
Can one Ethernet cable really power a camera and a wifi AP at once?
Yes, through a PoE-powered pass-through switch. IEEE 802.3at budgets 30 W at the port and guarantees 25.5 W at the powered device, so the switch, camera and AP draws must total 25.5 W or less. Example: a 5 W switch, an 8 W camera and a 10 W AP total 23 W and leave a 2.5 W margin, while 13 W plus 12 W plus 5 W needs an 802.3bt uplink or a second cable.
Does the access point go inside the enclosure with the switch?
No. Stainless walls screen 2.4 GHz and 5 GHz signals like a Faraday cage, so an AP inside the box serves almost nobody. Mount it on the outside face of the box or just above it, and feed it through its own IP66-rated gland with a drip loop below. The outside mounting also keeps the radio's heat out of the sealed interior.
What size box fits a PoE pass-through switch and the extra cable?
Start at the 10 x 8 x 4 in catalog box, about 306 in³ of interior volume. That holds the switch, the uplink splice and two outgoing glands with room to dress cable; its nominal interior dimensions are on the product page. The next size down, 8 x 6 x 4 in outside, fits only the smallest units.
What does full sun do to the interior temperature?
Direct sun adds roughly 10 to 15 °C at the wall surface. The example box runs 7 °C over ambient from a 5 W switch, so a shaded wall at 30 °C gives a 37 °C interior while a sunlit west wall lands near 50 °C. Shade the box or pick a switch whose datasheet carries that temperature.
Can I drill a small drain hole in the bottom of the box?
A sealed Type 4X / IP66 box keeps its rating only while every opening stays closed, and a drain drops the assembly to that opening's protection. NEC 314.15 permits 3 to 6 mm drainage openings in boxes listed for damp or wet locations. Keep the bottom sealed, loop every cable, and the box sheds rain without a drain.
Do I need 316L stainless for a coastal AP box?
Take 316L within reach of salt spray, pools or washdown lines. Chloride deposits pit 304 even at room temperature, and the stress-corrosion threshold sits near 60 °C (140 °F) for both grades, which the molybdenum in 316L does not move; its benefit is higher pitting and crevice resistance. Dry inland walls are fine in 304.
