I want to run about 100 meters of Ethernet cable out my attic and down a drainpipe. The cable will be exposed to the elements, and attached to a gigabit switch (indoors) at both ends.

What kind of cable do I need? Can I get a basic Cat5E bulk cable, or does the length and exposure mean I should opt for Cat6? Or is there some other outdoor-rated specification of wiring that I should be using?

  • I suspect this would get better answers on superuser.
    – Jay Bazuzi
    May 9, 2011 at 1:19
  • @Jay: Or even better, serverfault.com
    – Macke
    May 10, 2011 at 21:52
  • 1
    @Marcus - we'd regard it as offtopic on Serverfault as its talking about a home network. @Portman - I'd personally be unhappy about running copper wire outside of the house due to the risk during a storm. As far as I'm concerned, the "outdoor-rated specification" for network wiring is called "fibre optic" though I appreciate that's overkill for most of us at home.
    – Rob Moir
    May 10, 2011 at 21:57
  • 1
    I would use one of those wireless cables::) Aug 5, 2012 at 14:22

5 Answers 5


You normally want to use outdoor flooded cable (also called gel-filled) as it is designed to weather the elements. I have a few clients who have gone with outdoor flooded & shielded cable as they were worried about interference on the outdoor runs. Also look for UV-resistant cable if it's not going to be buried or otherwise enclosed.

As for Cat 5e versus Cat 6, for home use it probably won't matter as you most likely running 100/1000B-T Ethernet and it will run fine on both Cat 5e or Cat 6. If you want to try to future-proof your cable--or the price difference is negligible--you can go for Cat 6.


100 meters is quite a long way for copper Ethernet (Google search) and if I remember correctly, there might be some problems with potential difference (not to mention lightning). Did you consider fiber optics? I think the equipment is priced quite reasonably and you would get rid of all speed & potential problems at once.

  • 1
    Yes if I remeber correctly, Ethernet is limited to 95m or so before very noticeable performance degradation. ***Actually it looks like longer lengths are sometimes possible: en.wikipedia.org/wiki/Cat_5e#Maximum_cable_segment_length
    – jamesbtate
    May 10, 2011 at 17:22
  • Reliable transmission is one thing and fast reliable transmission is another. If there are gigabit switches on both sides, I guess that the poster would like to get some decent speed out of the link. That is very unlikely once you get close to the length limit.
    – zoul
    May 10, 2011 at 19:10
  • It's probably going to end up being closer to 85 meters. Also, I've run 100 meters at my previous home without any issues. I always thought the performance risks of longer runs were a bit overblown.
    – Portman
    May 11, 2011 at 15:42

That length would worry me, but when I was doing infrastructure work we were required to use fiber for runs of the length you indicated for reliability and crosstalk issues. If your switches support add-on cards for a fiber module, that would be your best (albeit probably most expensive as well) solution.

Another option would be to go wireless. A wireless bridge with directional high gain antennas (a nice Yagi antenna won't set you back much) on both sides of the "run". This is a great solution for getting networking in a detached garage or workspace. But line of sight could be an issues if you have large dense objects (especially anything metal of course) in your intended path.


You can get proper outdoor network cable in varying lengths. I'd recommend cabling with an outer coating of PE rather than PVC, hence impermeable to water.

  • 1
    PVC is used for plumbing, so water permeability shouldn't be an issue. PVC is not recommended outdoors because it's damaged by the UV in sunlight.
    – Niall C.
    Nov 20, 2012 at 16:53

There is no cable difference between 5E and 6 - only an installation is rated as cat6 - depending on how well the connections are made

Any decent cable should survive outside reasonably well. Building code-wise we are supposed to run fiber between buildings in case of lightning strike.

  • 5
    This is very, very wrong. CAT5E and CAT6 do have different cable types.
    – Fake Name
    Oct 31, 2012 at 0:11

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