Powering a plug-in floodlight camera from an outdoor light box

Short answer: you leave the round floodlight box outside as a sealed cord pass-through, and you put the receptacle indoors. Fish the camera's cord through one sealed entry into the garage and plug its adapter into a new GFCI on the garage side of the same wall. An outlet in that box outdoors needs a weather-resistant GFCI plus an extra-duty in-use cover, and the usual 1.5 in [38 mm] round fixture box is too shallow for either. Leave the adapter outside and heat finishes it. A 24 W adapter raises the air in a 4 x 1.5 in [102 x 38 mm] box about 40 C [72 F] above the wall. Full sun already puts a south wall about 30 C [54 F] above the air. The whole fix is one hole and an afternoon.

Can you put a normal outlet in a floodlight box?

No — a plain indoor receptacle in an outdoor box fails three ways at once: it is not weather-resistant, it has no in-use cover for a plug that stays connected, and the usual 1.5 in [38 mm] deep round box has no volume left for conductors.

Rain gets there first. An indoor receptacle face is built for dry air; UV makes it chalk and crack within a few seasons, and hose spray lands straight on the slots. A flat weatherproof cover is rated with the lid shut, and your camera cord holds that lid open for years. The NEC's wet-location receptacle rules call for an extra-duty while-in-use dome over any 15 A or 20 A outdoor receptacle, closed around the plug.

Mounting the camera over the outlet adds nothing either. The camera's mounting gasket seals the camera to the box, and it is not a receptacle cover of any kind. The outlet you already bought is the right part for the indoor half of this job. For the outdoor rules, read when you need a weather-resistant GFCI outdoors; for what a full outdoor receptacle install involves, see fitting a 14-50 EV outlet in an outdoor enclosure.

What does a compliant outdoor outlet need?

Three parts, all rated for wet locations: a weather-resistant GFCI receptacle, an extra-duty while-in-use cover, and a box at least 2 in [51 mm] deep — the domes add about 2.5-3 in [64-76 mm] in front of the face.

Weather-resistant means the WR marking: corrosion-resistant contacts and a UV-stable face made to sit in the rain, with tamper-resistant shutters standard on 15 A and 20 A outdoor models. Cover makers rate the extra-duty domes NEMA 3R, which is their own rating, and the dome has to swallow the whole adapter body with the lid shut.

Depth is where the round box stops you. A GFCI body is about 1.25 in [32 mm] deep, so in a 1.5 in [38 mm] can the device fills the box and your wires have nowhere to go under the NEC's box-fill rules. Adapter plates exist for 3.5 in and 4 in [89 and 102 mm] round or octagonal openings, and they give you a device opening without giving you depth. Give an outdoor receptacle a weatherproof box 2 in [51 mm] deep, or surface-mount one on the siding.

Then look at what shares the wall: your camera mounts on that same round box, so the dome would sit right behind the camera housing. That is the practical winner for the cord-through route — the box keeps one job, being the camera's sealed mount, and the receptacle lives inside where it runs cool and tests easy.

Where should the camera's power adapter live?

Inside the garage, plugged into the new GFCI: plug-in adapters are typically classed for 40 C [104 F] ambient — read the marking on your case — and a south wall beats that number before the adapter warms itself up.

Here is the arithmetic on a captive adapter, with a typical switcher at 85% efficiency as the assumption; swap in your adapter's own numbers:

• Output: 12 V DC x 2 A = 24 W
• Input: 24 W / 0.85 = 28.2 W; losses into the box = 28.2 - 24 = 4.2 W
• Surface of a 4 in [102 mm] round box, 1.5 in [38 mm] deep: sides plus ends ≈ 44 in² [0.028 m²]
• Heat through stainless: 3.7 W/m²K, so 4.2 W / (3.7 x 0.028) ≈ 40 C [72 F] rise
• Sun on a dark south wall adds about 30 C [54 F] over air: at a 30 C [86 F] afternoon the wall sits near 60 C [140 F], the box air near 100 C [212 F]

So an adapter rated 40 C ambient would live at 100 C. Halve the load and the self-heating still adds a 20 C rise on top of the sun. Indoors, the same brick sits at garage air temperature and its marking holds with margin.

How do you run the cord through the wall to a garage outlet?

Move the branch cable from the round box to a new single-gang box on the garage side of the same wall, land a GFCI in it, pass the camera cord through the old cable entry, and mount the camera on its gasket — an afternoon's work.

What you need: a voltage tester, an old-work single-gang box, a 15 or 20 A GFCI receptacle, a cable connector, a drywall saw, a drill with a 0.75-1.125 in [19-29 mm] bit or step bit, a domed cable gland or rubber grommet matched to the cord, UV-stable sealant, and the camera's mounting hardware.

1. Open the branch breaker and lock the panel; confirm the floodlight wires are dead with the tester.
2. From the garage side, find the cable feeding the round box, disconnect it at its source, and pull it back inside with its length intact. If it runs short, land it in the new box and splice an extension there — splices belong in a box you can open.
3. Cut a single-gang opening directly behind the round box and set the old-work box. Bring the cable in through a connector. Land the GFCI: hot to the brass LINE screw, neutral to the silver LINE screw, ground to the green screw.
4. With a metal box, bond it and strip paint at the contact surface — NEC 250.12 requires bare metal at grounding connections, and enclosure grounding and bonding has the full method.
5. At the round box, remove the old cable clamp and pass the camera cord through, plug first, from outside toward the garage. Enlarge the old cable hole only to the plug's widest point plus 1/8 in [3 mm].
6. Seal the entry with the gland body threaded into the hole, or the grommet plus UV-stable sealant where the plug has already passed. The seal grips the cord jacket and the dome sheds water.
7. Leave a drip loop outside so the cord sags below the entry; water running down the jacket drips off instead of following the cord in.
8. Mount the camera to the box ears with its gasket, snug. Wind works an unrelieved cord against the gland within a season — floodlight camera strain relief and gland covers the details. Restore power, press TEST on the GFCI, and confirm the receptacle drops dead; press RESET to bring it back.

What size hole does the camera cord need?

Size the hole to the plug's widest point plus 1/8 in [3 mm]: a molded two-prong adapter plug usually needs 0.875-1.125 in [22-29 mm], a small low-voltage barrel plug only 0.25-0.375 in [6-10 mm].

The small plug is the prize. If the adapter stays inside and only the low-voltage side crosses the wall, a 0.5-0.75 in [13-19 mm] gland with a sealing insert matched to the cord does the whole job — hole, seal and grip in one part. Check your cord first: a brick at the wall end sizes the hole to the plug; a brick mid-cord lets you route the low-voltage side and keep the hole small.

A molded plug through a drilled hole is its own job, because the hole ends up plug-sized and the seal closes back down to the cord. Getting a molded plug through an enclosure knockout works that case, and the gland and cutout guide lists thread sizes against hole diameters. Put your entry at the bottom of the box or through the back opening, deburr it, and keep the dome over the seal.

How do you know the job is sealed and wired right?

Three checks prove it: hose the mounted assembly for two to three minutes from about 3 ft [1 m], working top down, and inspect the garage side for water tracks; press TEST on the GFCI; and re-snug the gland nut a quarter turn after the first week, because seals relax.

Water that gets in shows as a track along the cord or a damp patch on the garage-side drywall rather than a drip — water inside a camera junction box after rain shows the usual hiding places. The GFCI's test button is the monthly check; it trips in a fraction of a second and resets clean. The adapter indoors runs warm to your hand, and that is the last attention it needs.

Which mistakes ruin a sealed floodlight box?

Four do the damage: an entry on top of the box, a plug-sized hole closed with a bead of caulk, the adapter left captive outside, and a flat cover over an outdoor plug.

• Entry on top. Water follows the cord downhill and into the box; use the bottom or the back. Cable glands facing up shows how fast that leaks.
• Caulk instead of a seal. A 1 in [25 mm] hole filled with caulk cracks within a year of sun and frost; a gland or grommet is a mechanical seal that moves with the cord.
• Adapter captive outdoors. The 40 C rise math above applies to any sealed box; adapters die quietly at their 40 C ambient mark, usually inside one season.
• Flat cover over a plug. It rates shut only; a cord under it turns the box into an open one in the next storm.
• Cable left behind. A live cable dead-ended in a box the camera covers is a trap for whoever opens it next, so disconnect it at the source and pull it out.

If the round box itself is rusted through when you open it, replace it rather than sealing over the rot. Stainless wall-mount enclosures start at 6 x 4 x 4 in [152 x 102 x 102 mm] outside, rated NEMA 4X / IP66 by the manufacturer and not UL listed, with a hinged door and a mounting panel — handy the day you swap to a hardwired camera. The enclosure selector sizes one by what you plan to keep inside.

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.

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