Can You Run Regular Ethernet Cables Outside?

Cable category terms like Cat5e and Cat6 have that industrial twang, so, understandably, some may assume they’re tough enough for outdoor use. And they can do more than just improve home internet, which is especially helpful for security cameras on your porch or in your yard. Sure, you can use standard Ethernet cables outdoors, but you can also run outside in a lightning storm with a ten-foot metal pole above your head — just because you can do something doesn’t mean you should. Standard indoor cables have a flexible PVC jacket, which is susceptible to sunlight. Over time it will fade and crack, exposing the internal components and ultimately degrading the connection.

Outside temperatures and rain accelerate the problem. The copper in an Ethernet cable won’t have proper protection from lightning strikes and other elements. Use a cable specifically rated for outdoor exposure, such as a direct-burial-rated cable made for an in-ground run across the yard. Direct-burial cables are specifically designed for this, and it will be written clearly on the cable jacket. Whatever the cable rating, it’s best practice to install surge protection on either end of the cable. While it requires additional hardware, you can avoid the risks of running copper outdoors by using outdoor-rated fiber optic cables instead of Ethernet, though any equipment exposed to the elements would still be at risk.

There’s a difference between a direct-burial and an outdoor Ethernet cable. Outdoor cables typically use a more weather-resistant polyethylene jacket (such as LLDPE or PE) instead of the standard PVC jacket. These materials are much better at resisting UV exposure, moisture, and wild temperature swings.

If the cable needs to run underground, opt for the direct-burial cable. These cables are capable of dealing with long-term exposure to moisture and the physical pressure of the surrounding soil. Depending on the type of direct-burial cable, it might use water-blocking tape, powder, or gel to keep the wire dry even if the outer jacket is damaged. 

Local ordinances may not be happy with your buried wire, so be sure to check local rules on conduit, depth, and the cable types permitted. If all you need is a short and simple exterior run to an outdoor access point, a Cat6 outdoor-rated Ethernet cable is appropriate. Always secure exterior cable runs with cable clips to avoid abrasion, and never sharply bend the cable, even if that means the run requires a bit of creativity.

To make sure your cable can be used outside, check the printing on it. It’s not always easy to read the small print, especially if it’s faded a bit, so you might have to make an extra effort for it; the color or category label means nothing where this is concerned. Terms like “CMX,” “OSP,” “UV-resistant,” “sunlight-resistant,” or simply “outdoor” are what to look for. Outdoor cables will also often list their jacket material, such as PE, HDPE, or LLDPE. The National Electrical Code (NEC) requires communications cables installed in buildings to be listed and marked, and UL’s guidance notes that cable evaluated for outdoor use is marked “outdoor” or “outdoor use,” so the rating shouldn’t be hard to confirm. Plus, the documentation that comes with them will state that they’re approved for direct burial or wet locations. 

Just note that an outdoor-rated cable doesn’t mean its inherent toughness makes it an excellent indoor application. Some exterior cables may not meet the requirements for indoor fire safety hazards, and that includes situations where only a small section of the outdoor cable is run inside. An unlisted outdoor cable generally can’t run more than 50 feet inside before it needs to terminate and transition to an indoor-rated cable, and shorter is better. Your best bet is to always read the cable’s markings and any associated literature. If you’re still unsure, check the local codes, especially for a permanent installation.