September 21, 2023

Sometimes, you need electrical enclosures that live outside. In those cases, the enclosure is exposed to weather and the elements, and finding something that can withstand the tough environment isn’t always easy.

Non-metallic enclosures are popular for outdoor applications because they never rust and don’t care about water. On the other hand, UV exposure is a concern, and it’s important to know which materials fair well in direct sunlight.

Additionally, you can learn about ways to protect any enclosure from UV damage, all of which is covered below.




Fiberglass is a common nonmetal material for outdoor applications because it is already UV-resistant. While fiberglass is prone to bleaching in the sun, that amounts to discoloration rather than a loss of structural integrity. Typically, fiberglass can hold up for years in direct sunlight with no discernable loss of material strength or shape.

Over enough time and sun exposure, the fibers will start to break down, but this is a slow process. Really, any material eventually takes sun damage, but fiberglass is rated for outdoor applications because it is so naturally resistant to UV damage.




Polycarbonate is not as UV-durable as fiberglass. As a result, fiberglass is the preferred choice, but polycarbonate can perform in outdoor applications too.

Polycarbonate is prone to bleaching, much like fiberglass. Eventually, polycarbonate will also suffer structural damage from UV exposure, and depending on the type of polycarbonate and thickness of the material, this can happen in years, rather than the decades it usually takes to break down fiberglass.

As a result, outdoor polycarbonate enclosures usually have treatments or other protective barriers that dramatically lower direct UV absorption in the electrical box, and this expands the lifespan of polycarbonate by years or more.


Additional Protection


What do these protections look like?

Ultimately, anything that can absorb or reflect UV light can work. There are a few common choices that are explained below, but before that, it’s worth mentioning something.

Regardless of the material used for your electrical enclosure, additional protection is worth considering for any outdoor box. As mentioned before, sunlight can eventually break down most materials, so an extra layer of protection is always valuable.


Paints and Coatings


With that said, paints and coatings are commonly used to expand UV resilience among nonmetal enclosures. Any opaque paint already provides a good layer of protection. The paint absorbs UV rays, and any UV absorbed by the paint doesn’t reach the enclosure material, reducing damage and extending lifespans.

Aside from paints, there are many resins and brush-on materials that absorb UV light well. Any of these is a viable option to protect your enclosures. You can even use a polycarbonate film on top of your enclosure to absorb the UV in place of the enclosure material. What matters is stopping the UV.




With this in mind, sometimes the simplest solution is the most viable. In plenty of outdoor applications, you can simply create shade for your enclosure. Shades can stop all direct UV light, preventing bleaching and deterioration quite effectively.

As you might imagine, the key to shading an enclosure is to ensure that your shade stops as much light as possible. A partial shade is better than nothing, but an opaque shade is the best choice. And, if you can make a shade that is weatherproof and durable, you won’t be replacing it or repairing it at regular intervals.

Regardless, any UV light that doesn’t reach your enclosure also won’t harm it.