Radio-Friendly Material

ABS and polycarbonate let Wi-Fi through; metal doesn’t. Keep the ESP32’s PCB antenna clear of batteries, relays and metal mounting plates, or choose a board with an external antenna connector.

The Right IP Rating

The first digit is dust protection, the second water. IP65 handles rain and hosing; IP67 handles brief submersion. Indoors, any closed box will do.

Enough Space

Allow room for the USB plug, wire bend radius, terminal blocks and airflow. A DevKitC is about 55 × 28 mm, but with cables it needs much more. When in doubt, go one size up.

Sealed Cable Entry

A drilled hole ruins the IP rating. Use cable glands sized to your cable, and point them downward so water drips away rather than running in.

Heat and Sun

A dark box in direct sun can get very hot, which shortens battery life and skews temperature readings. Use a light colour, shade the box, and mount climate sensors outside in a radiation shield.

A clear lid means you can read an OLED, e-paper or TFT display, see status LEDs and check that everything’s working without opening the box. This 2-pack (about 4.7 stars from 1,250 ratings) pairs a black ABS body with a transparent cover in the same 100 × 68 × 50 mm size as our top pick, sealed to IP65. It’s ideal for weather stations with a local readout, garden sensors with an e-paper display, or a garage door controller with status lights. A clear lid also lets light reach a BH1750 light sensor or solar cell inside. Mount the display close to the lid to avoid reflections.

This 150 × 110 × 70 mm box is the most-reviewed enclosure in this guide (about 4.5 stars from 4,300+ ratings) and fills the gap between the small and large picks: room for an ESP32, a couple of sensor boards and an 18650 holder. Its white finish is a real advantage outdoors, because it reflects sunlight and stays cooler than black boxes, which helps both battery life and temperature accuracy. The IP65 ABS body suits gardens, sheds, garages and greenhouses.

For permanent outdoor installs such as solar-powered weather stations, pump controllers, gate controllers or LoRa gateways, a hinged lid makes maintenance far easier than unscrewing four corners on a ladder. This IP67 box (about 4.7 stars from 1,834 ratings) measures 11.2 × 7.7 × 5.1 inches, enough for a charge controller, a battery, an ESP32 and a relay board. Its ABS construction keeps it radio-friendly; mount antennas outside or close to the lid for best range.

Tiny boards like the XIAO ESP32C3/C6/S3 and ESP32-C3 SuperMini deserve tiny cases. These 60 × 36 × 17 mm ABS boxes (about 4.6 stars from 1,761 ratings, 5-pack) are just big enough for one of those boards plus a small sensor, which makes them perfect for indoor room sensors, BLE beacons, Bluetooth proxies and plug-in USB gadgets. Drill a slot for the USB-C plug and a few ventilation holes near the sensor. They’re not waterproof, so use them indoors. Only 20 were in stock when we checked.

If your ESP32 lives in a distribution board, a pump-room cabinet or an industrial control panel, it should clip onto the same 35 mm DIN rail as the breakers and contactors. This DIN rail carrier (about 4.7 stars from 38 ratings) holds a PCB of 47.35 × 72 mm, so mount your ESP32 on a perfboard or adapter cut to that size, then snap it onto the rail. Alternatively, Waveshare’s industrial relay boards in our relay guide already come in rail-mountable cases. Only 19 were in stock when we checked.

Every cable that enters an outdoor box is a potential leak, and cable glands are how you keep the IP rating. This TUPARKA assortment (about 4.6 stars from 2,044 ratings) includes 50 glands in six sizes, PG7 to PG19, covering cables from 3 to 16 mm, with gaskets and a storage box. Use PG7 for thin sensor and USB cables, and larger sizes for power and multi-core cables. Drill the hole to the gland’s thread size, fit it from outside, tighten the nut inside, then tighten the dome around the cable. Mount glands on the bottom of the box where possible.

A perfectly sealed box isn’t always a dry box. As it heats in the sun and cools at night, it breathes air in through the tiniest gaps and moisture condenses inside, eventually corroding pins and connectors. A breather vent with a waterproof membrane equalizes pressure while keeping water out. These M12 × 1.5 vents (about 4.7 stars from 44 ratings, 2-pack) screw into a drilled hole like a cable gland. Fit one on the underside of the box, and add a silica gel pack for extra protection in humid climates.

A temperature sensor inside a sealed box in the sun will read far too high. Professional weather stations solve this with a louvred radiation shield (a Stevenson screen) that blocks sun and rain while letting air flow over the sensor. Ambient Weather’s WH31-SRS (about 4.5 stars from 193 ratings) is made for its own sensors, but it’s a popular, inexpensive housing for a BME280 or SHT31 breakout on a short cable from your ESP32 enclosure. It includes mounting hardware and a U-bolt for poles and fences. Check the internal space against your breakout before buying.

Loose boards rattle, short against each other and break solder joints. A standoff kit lets you mount every board securely off the enclosure floor, and this 480-piece set (about 4.6 stars from 923 ratings) covers the three common sizes: M2 for small boards, M2.5 for many dev boards and displays, and M3 for relay boards and larger modules. Use nylon screws or washers where a standoff could touch a trace, and fix the standoffs to the box floor with short screws or a dab of epoxy.

Single sensor node?

The Zulkit 100 × 68 mm box plus a PG7 gland.

Project with a display?

The clear-cover IP65 box.

Relays or a power supply?

The LeMotech 200 × 120 mm box.

Solar weather station?

White 150 × 110 mm or hinged IP67 box + radiation shield + vent.

Indoor room sensor?

A mini 60 × 36 mm case with a XIAO board.

Electrical panel?

The DIN rail carrier, or a rail-mount relay board.

Will Wi-Fi work inside a plastic enclosure?

Yes. ABS and polycarbonate barely affect 2.4 GHz signals. Range drops more from what’s inside the box: keep batteries, relays, metal plates and wiring away from the ESP32’s antenna end. In a metal cabinet, use a board with an external antenna connector and mount the antenna outside.

How do I stop condensation inside an outdoor box?

Fit a membrane breather vent so pressure can equalize without sucking in wet air, mount cable glands on the bottom, add a silica gel pack, and keep the box out of direct sun. A conformal coating spray on the PCB adds another layer of protection in very humid places.

Why does my temperature sensor read high inside the box?

The ESP32, regulator and sun all heat a sealed box. Mount the sensor outside the enclosure in a radiation shield on a short cable, or at least in a ventilated corner away from the board. Our ESP32 sensors guide covers sensor placement too.

Should I 3D print my own enclosure?

3D-printed cases are great indoors and give a perfect fit. Outdoors, PLA softens in summer heat; PETG or ASA last much longer, but printed walls are rarely as waterproof as a gasketed commercial box. Many makers combine both: a commercial IP65 box with a 3D-printed internal mounting plate.

Can I put mains wiring in these boxes?

Project boxes are general-purpose enclosures. For mains voltage, follow your local electrical code, use rated terminal blocks and cable entries, keep mains and low-voltage wiring separated, and have a qualified electrician do or check the installation.