Ask LH: Can I Connect Two Buildings With Ethernet?

Ask LH: Can I Connect Two Buildings With Ethernet?

Hello Lifehacker, I would like to connect a secondary building that is 300 metre away metres from our main house. There is no line of sight so wireless seems to be not an option. I looked into cable and found the Cat5e outdoor direct burial is priced reasonably enough to run the 300 metre distance. But can I do that length without a problem? Thanks, Cable Convert

Ethernet picture from Shutterstock

Dear CC,

Sorry to be the bearer of bad tidings, but this is extremely unlikely to work. It’s widely accepted that you can’t run a standard cable more than 100 metres without incorporating a booster or other enhancement technology. A straight connection almost certainly won’t work. While you might occasionally go over 100 metres, tripling the length just isn’t going to fly.

Presuming there’s no other interim building where you can house a repeater or booster, you’ll need optical fibre rather than standard ethernet to make this work — and that will cost a lot more and require slightly different equipment at each end. Your only alternatives are to spend that money or set up a separate connection at the destination (which will be expensive and involve more monthly internet charges).


Got your own question you want to put to Lifehacker? Send it using our [contact text=”contact form”].


  • You can get weather proof extenders so there is no need for intermediate building to house them, and they run off of PoE so no need for a power source other than at the one end.

    You still need to maintain the 100m length per segment of cable between repeaters and not all repeaters can be daisy chained so you need to buy the ones particular to your application as well as the appropriate PoE injector if your switch isn’t up to the job.

    I’d be more worried about the legalities of doing this, running past other peoples properties and such.

    • Those extenders are really expensive and can only span 300m with 2 units and require a powerful PoE injector and a PoE compatible device at the end of line.
      Voltage difference and ground loops are another problem with hooking 2 separate buildings with copper network.
      All the above makes Optic Fibre look like a better option.

      Ethernet over Powerline could be an option to investigate. or rigging a line of sight mast so you can go with a Wireless Solution.

      • Not necessarily true, with the appropriate equipment you can get over 1Km with a CAT6 albeit only 10Mbps and around 800m at 100Mbps.

        Fibre might not be suitable for a variety of reasons, we really haven’t got enough information to say that XYX is the solution to your problem.

  • Tp Link sell basic media converters you could use after you’ve got the fibre installed by a technician. The cost would be a lot more than ethernet but you may be able to get a discount if you provide the trench, help, etc.

  • Direct LoS will usually give you best speeds/throughput for radio-based data traffic, but even without a direct path ‘tween the antennas you could still try it and see – look at most home/office WiFi installs…

    You could still get an acceptable signal path depending on what’s stopping the LoS and where’s it’s palced in the actual radio pathing, or even look at bouncing the signal off of nearby structure etc, with or without using direction antennas.

    It’s called Suck It and See.

  • My first attempt at posting seems to have failed, apologies for potential duplication.

    Line of sight is overrated, unless of course there’s an actual mountain in between. There are several wireless technologies that will manage that distance fine. Sometimes a high-gain directional antenna will be required. (Don’t think domestic WiFi, though that may also succeed with some directional antennas.

    Alternative solution would be to create a high speed serial link. Wikipedia has a starting point:

    There is also a technology called PAPL, Permitted Attached Private Lines, which uses existing phone copper:

    Ethernet is not the solution in my opinion, embedded repeaters are really asking for problems, unless you can guarantee that they’re protected against the weather.

  • Another option is to use point to point wireless on a roof mounted system.

    While line of sight may be an issue on more ground level, there might be luck going up.

    I’m use to using ubiquiti for doing links over a kew KMs, so they could do the job for 300m.

  • Do it via a wireless router with a parabolic reflector behind the WiFi antenna with another router at the other end in a bridge arrangement.
    You can get up to about 1 Km using this method.
    look up
    Do a search for 2.5Ghz or 5Ghz antennas on the web and that will also cover the subject.
    Lifehacker (US) has covered it before in Sept 2011.
    Old routers are cheap and if you can flash them with dd-wrt, bridge and other connections are covered.
    Home made antennas are also cheap in a d.i.y. situation so if you study it up you will be able to do it with not much costs involved.

  • Crikey, Im appalled people are seriously over thinking this. I personally have a airfibre link from ubiquity. Its 130mbit bi directional – so that’s 130mbit IN EACH direction REAL throughput none of this silly wifi rated speeds.

    The radios cost about $130 each. I have had mine up for a year and a half and have NEVER had to touch them once set up, they reboot themselves if they crash and are essentially ISP quality.

    They have a theoretical range of 15 km however at 500 meters im getting full throughput. It essentially means that I have a virtual cat5 cable between the two buildings……

    Its nice, cause I don’t have a phone line into my house… yet my mate 500 meters down the road does….. im sure you can see why I use it now. Their wireless APs are all over UQ now, I have one on the ceiling in my kitchen.

    The install cost less than hooking copper up to my house. I think im winning.

    Look em up – ubiquiti

  • yeah my bad it was the nanostation.

    I had recently been talking about air fibre, as a local utility company had installed one on their water tower for their own town wide intranet.

  • Something else to consider when burying copper cable in the ground is lightning ground strike. My comm’s cabling knowledge is a bit out of date, but I’m fairly sure running CAT cable between buildings is in breach of Aus standards or, at best, is extremely bad practice.

Log in to comment on this story!