内容来源：https://www.engadget.com/2294283/ethernet-cables-use-outside-explained/

内容总结：

普通网线能否在户外使用？技术上可行，但并不建议这样做。Cat5e、Cat6等网线名称带有工业感，容易让人误以为足够坚固、可用于室外，但实际上室内标准网线采用柔性PVC外护套，长期暴露在阳光下会褪色、开裂，导致内部组件外露、连接性能下降，室外温度和雨水还会加速这一过程。此外，网线中的铜芯缺乏防雷击和其他自然因素的保护。因此，户外布线应选用专门 rated 的室外网线，如直埋级网线，其外护套通常采用更耐候的聚乙烯材料（如LLDPE或PE），能更好地抵抗紫外线、潮湿和剧烈温度变化。直埋网线还可通过阻水带、阻水粉或阻水凝胶保持内部干燥。无论选用何种网线，建议在两端安装浪涌保护装置。若需避免铜缆户外风险，可改用室外级光纤电缆，但暴露在外的设备仍面临风险。铺设地下线缆前应查阅当地法规对导管、埋深和允许线缆类型的规定；短距离简单室外布线可选用Cat6室外级网线，并用线夹固定、避免磨损和急弯。辨别网线是否适用于室外，应查看线身印字，寻找“CMX”“OSP”“UV-resistant”“sunlight-resistant”或“outdoor”等标识，室外网线通常还会标注PE、HDPE或LLDPE等护套材料。美国国家电气规范（NEC）要求建筑物内通信线缆须列出并标记，UL指南指出经评估的室外线缆会标注“outdoor”或“outdoor use”，随附文档也会注明是否允许直埋或用于潮湿环境。需注意，室外级线缆不等于适合室内使用，部分室外线缆可能不满足室内防火安全要求，未经列表认证的室外线缆在室内一般不得超过50英尺，且越短越好，永久安装前应查阅当地法规。

中文翻译：

可以把普通以太网网线布设在户外吗？
能做某事，并不意味着就该去做。
Cat5e、Cat6这类网线等级术语自带一种工业气息，因此有人会想当然地认为它们足够结实，可以用于户外。而且它们的作用不止是改善家庭网络，这对门廊或院子里的安防摄像头尤其有用。当然，你可以在户外使用标准以太网网线，但你也可以在雷暴天举着一根三米长的金属杆在户外奔跑——能做某事，并不意味着就该去做。标准室内网线采用柔性PVC外皮，容易受阳光影响。随着时间推移，外皮会褪色开裂，暴露内部组件，最终导致连接质量下降。
室外温度和雨水会加速这一问题。以太网网线中的铜线无法获得针对雷击和其他因素的适当保护。应使用专门 rated 适用于户外环境的网线，例如为穿越院子的地下布线而设计的直埋级网线。直埋网线正是为此设计的，网线外皮上会明确标注。无论网线等级如何，最佳做法是在网线两端安装浪涌保护。虽然这需要额外硬件，但你可以改用户外级光纤代替以太网，从而避免在户外布设铜线带来的风险——不过任何暴露在自然元素中的设备仍然存在风险。
使用正确的户外网线
直埋网线和户外以太网网线是有区别的。户外网线通常采用更耐候的聚乙烯外皮（如LLDPE或PE），而不是标准PVC外皮。这些材料在抵抗紫外线、潮湿和剧烈温度变化方面要好得多。
如果网线需要埋入地下，应选择直埋网线。这类网线能够承受长期潮湿和周围土壤的物理压力。根据直埋网线的类型，它可能使用阻水带、阻水粉或阻水凝胶，即使外皮受损也能保持线芯干燥。
当地法规可能不允许你随意埋线，因此务必查阅当地关于导管、埋深和允许使用的网线类型的规定。如果你只需要一段简短的外墙布线连接到户外接入点，Cat6户外级以太网网线就可以了。户外布线务必使用线夹固定，以避免磨损，并且切勿急剧弯折网线，即使这意味着布线需要一点创意。
如何判断以太网网线是否为户外级
要确认网线能否用于户外，请查看网线上的印字。小字并不总是容易辨认，尤其是有些褪色的时候，所以你可能需要格外费心；颜色或等级标签在这方面毫无意义。要寻找“CMX”“OSP”“抗紫外线”“耐日光”或直接标注“户外”等字样。户外网线通常还会标明外皮材料，如PE、HDPE或LLDPE。美国国家电气规范（NEC）要求建筑物内安装的通信网线必须经过列名和标记，UL的指南指出，经评估可用于户外的网线会标注“outdoor”或“outdoor use”，因此等级确认应该不难。此外，随附的文件会说明其获准用于直埋或潮湿场所。
需要注意的是，户外级网线并不意味着其固有韧性使其适合室内应用。某些户外网线可能不满足室内消防安全要求，这包括只有一小段户外网线布设在室内的情况。未经列名的户外网线在室内一般不能超过50英尺，之后必须端接并过渡为室内级网线，而且越短越好。最稳妥的做法是始终阅读网线上的标记和任何相关文件。如果仍不确定，请查阅当地规范，尤其是对于永久性安装。

英文来源：

Can you run regular Ethernet cables outside?
Just because you can do something doesn't mean you should.
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.
Use the right outdoor cable
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.
How to tell if an Ethernet cable is outdoor-rated
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.