Running Outdoor Ethernet Cable: Tips, Techniques and Best Practices

Shielded and especially shielded direct burial Ethernet cable is quite thick. If your installation involves wiring up outdoor WiFi access points or IP surveillance cameras the water resistant housings of these devices may be too small/tight for the thicker varieties of cable. Cat6A shielded direct burial cable sounds great until you find yourself in a situation where you cannot physically install it! Give serious consideration to Cat5e outdoor unshielded or even shielded (when necessary) to make for a much easier installation. Often, these devices do not require any speed above 1 Gigabit. Remember, Cat5e still supports 2.5GBASE-T (2.5 Gbp/s) and also supports 100W DC PoE.

Here are some easier to work with options for above ground runs:

Cat5e Outdoor Ethernet Cable｜Unshielded

Cat5e Outdoor Ethernet Cable｜Shielded

Cat6 Outdoor Ethernet Cable｜Unshielded

Here is the easiest direct burial option that trueCABLE sells:

Cat6 Gel Filled Direct Burial Ethernet Cable｜Unshielded

Do I need shielded Ethernet cable for outdoors?

You might. It all depends on what your Ethernet cable is running next to before and after it gets outdoors and if it is suspended up in the air experiencing direct airflow. Generally speaking, shielded Ethernet cable is recommended for:

• Runs that get too close (closer than 8” on parallel) to 120V or higher AC circuits will require shielded Ethernet cable.
• Runs that get too close to powerful motors, transformers, and other sources of extremely high EMI (electromagnetic interference) will require shielded Ethernet cable.
• Shielded Ethernet cable is required to drain off ESD (electrostatic discharge) from runs that are suspended on a messenger wire and subject to air movement.
• If your area is subject to RFI (radio frequency interference) from radar transmitters, AM radio transmitters, or other significant sources of RFI then shielded Ethernet cable may be required along with an RFI site survey by a professional contractor.

Other than the factors listed above, shielded Ethernet cable is generally not required. What trueCABLE recommends is to use shielded Ethernet cable when you know it is needed, but otherwise use unshielded Ethernet cable. Shielded Ethernet cable greatly increases cable thickness, weight, installation complexity, and must be bonded to ground correctly to avoid ground loops and floating cable shields.
 

Shielded Ethernet cable significantly increases installation complexity. Use it wisely! 

Mitigating Ground Loops and Extreme ESD (Lightning)

Ground Loops

If you’re running shielded Ethernet cable outside between two buildings (buried or not), it is very important to avoid what is known as a ground loop. You do not want this to occur, as data packet loss or even equipment damage can result.

This situation arises when the building electrical mains have different ground potentials. This can result in voltage injection through the cable if the cable is running to ground at both ends through the different AC grounds. Mitigation strategies can be found in How to Fix a Ground Loop.

A simple way of avoiding ground loops is to simply opt for unshielded Ethernet cable, if possible. In some cases, it is NOT possible.

Lightning strikes and other ESD Issues

Are you at risk for a lightning strike? Technically speaking, we all are. Just ask the poor golfer who chose to golf at the wrong time…. Yikes! On a more serious note, some regions are significantly more affected by frequent lightning strikes than others. Using the Internet, find out if your area is in a high risk zone. If so, then any outdoor Ethernet cable is at risk whether above ground or buried.

Generally, Ethernet cable that is not buried and does not span structures is at lower risk for lightning strikes, so this is less of an issue. A great example of this type of installation is Ethernet cable used for IP surveillance cameras that are all attached to the same structure. That said, it does not hurt to use ESD protection regardless. Better safe than sorry.

A rather detailed and extensive blog with installation examples and recommended hardware is found in When Lightning Strikes! Ethernet Data Cable and Lightning Protection.

When is fiber optic cable the better (or only) option?

One of the biggest differences between indoor installations and outdoor installations is the need to pay close attention to your run length, due to ambient temperatures. 

Have you ever heard the story about the Ethernet copper cable that worked great during the winter but not the summer or the Ethernet cable that only works in the morning? Temperature affects copper communications cable negatively. Essentially, as copper heats up it becomes more resistant to passing signals.

• Solid copper Ethernet cable is subject to length restrictions as you exceed 68℉ ambient air temperature.
• All outdoor above ground Ethernet installations are affected by temperature induced length restrictions, unless your outdoor temperatures stays at 68℉ or less year-round. Essentially, you will need to “de-rate” (shorten) your runs so expect that and plan for it. Direct burial installations may or may not be affected, depending on burial depth and if any cable is exposed above ground.

Use the worst case possible upper ambient temperature to base your maximum run lengths. Check historical weather data during the summer for the last 10 years to reveal the maximum temperature you are likely to experience. If your cable will be running through an attic or on top of a roof, be sure to base your maximum worst case ambient temperature upon that, where temperatures will typically be highest. For a detailed temperature reduction chart, please refer to Temperature's Effect on Ethernet Cable Length.

A quick rule of thumb: Restrict your outdoor runs to 250 feet maximum when using unshielded Ethernet or 275 feet maximum when using shielded Ethernet so you are covered up to 135℉. Yes, it is getting hotter each year and you probably should take this into account.

If you need to go longer, the workaround is to use intermediate PoE powered switches and keep each segment of copper Ethernet cable to the limits as specified above. This way you can still transmit PoE to end point devices and keep the installation complexity reduced. Your equipment costs will increase, however, as additional outdoor grade PoE switches will be required and you will need to find a place to mount them. This does not work for underground runs, however.

So, fiber optic to the rescue? Perhaps. There are situations where fiber optic is ideal. A building to building fiber backbone that is not expected to carry PoE is the perfect case for this. Fiber can let you go thousands of feet depending on your bandwidth needs, and the costs are not much higher. OM4 MMF (multimode fiber) can easily handle 1,310 feet at 10Gbps, for example, and cost very little and require no termination hassles! See Using Fiber Optics to Extend Your Ethernet Network Beyond Copper's Limits for detail on how to accomplish this.

Tips and tricks for Installing Ethernet cable in conduit

Of all the ways to destroy an otherwise good Ethernet cable, conduit pulls are probably the #1 most likely way to do it. Well, if you do it incorrectly you are nearly guaranteed to have issues with cable damage.

Pros:

• Direct burial requires digging twice as deep as runs installed into conduit.
• Conduit permits easy cable replacement if the cable should stop functioning.
• PVC conduit will provide light duty protection for your Ethernet cable.
• You may achieve superior cable protection (essentially immune from damage) if intermediate metallic threaded conduit is used.
• Metallic conduit doubles as a super effective cable shield, which negates the need to use shielded Ethernet if the EMI source you seek to avoid is underground next to the Ethernet cable (like an electrical circuit running parallel to it.)

Cons:

• Cable runs are extremely susceptible to damage during the cable pulling process.
• Conduit installations are moderately labor intensive.
• The use of conduit, especially metallic conduit, will drive up costs significantly.
• If you are willing to trade off higher expenses for less labor, then rent a trencher machine.
• Sizing of the conduit is critical for the number of runs, and replacement of the conduit for a larger size after the fact is virtually impossible.   This means no room for errors!

Best practices:

• Conduit should be buried at least 10” deep, if buried.
• Use direct burial grade Ethernet cable for underground conduit runs.
• Gel filled direct burial Ethernet is the most effective variation of underground cable.  It is immune to water infiltration.
• Always use the correct trade size conduit for the number of runs, which is based upon a maximum 40% initial fill ratio. Conduit trade size and the cable jacket diameter determine maximum count. A conduit sizing chart can be found in the Conduit Fill Chart for Ethernet and Coaxial Cable or above. 
• Never use conduit less than ¾” trade size or cable damage may result.
• Always use synthetic wax based cable lubricant when pulling through conduit, and apply  at the feed end liberally.
• Conduit should be rigid, not flexible, as cable jacket damage may result during the pull process.
• Conduits should not exceed 100 foot continuous segments.  There should be intermediate pull points if 100 feet is exceeded, and more installation personnel to assist at each pull point.
• Conduits should not have more than two 90° bends in the same segment.
• Use plastic protective sleeves on conduit ends to prevent slicing or abrading the cable jacket at the feed end.
• Prevent binding/kinking of the cable as it feeds into the conduit.  Conduit pulls are almost always two or more person operations.
• Utilize a pre-installed pull string to pull cable through conduit, preferably with a swivel and pull-eye to help prevent cable binding.  Use of a wire mesh sock and swiveling pull-eye is the best method.
• Keeping the pull string inside the conduit in case you need to replace a damaged cable in the future is a wise move!

Please see this basic overview video on how to work with EMT conduit, including cutting and measurement: Working with EMT Conduit: Cutting and Measurement

For more detail and guidance on conduit fill charts for Ethernet and coaxial cable, please see: Conduit Fill Chart for Ethernet and Coaxial Cable

To make digging a trench more efficient, a trencher machine can be rented from the local equipment rental store. Use eye and ear protection.

Always contact your utility companies and request they come out and mark where your utilities are located BEFORE you dig. 

Tips and tricks for Installing direct burial Ethernet cable

Another option for running Ethernet cable underground is to directly bury it. This means no conduit necessary, you just chuck it into the dirt.

Pros:

• Direct buried Ethernet cable is buried and out of sight, and out of mind.
• Going the direct burial route is not expensive if you use a shovel (good luck with that.)

Cons:

• Unfortunately, due to the depths required direct burial runs are very labor intensive.
• Cable is more susceptible to damage from heavy vehicles or underground rodents when not installed into conduit.

Best practices:

• Direct burial should be buried 18 to 24” deep.
• Use direct burial Ethernet cable only, with preference towards the gel filled variety as it is 100% immune from water infiltration.
• To help with drainage, bed  the bottom of the trench with 1 to 2” of pea gravel.
• Leave a few lazy “S” shapes in the trench to allow for freeze/thaw cycles and ground movement.  DO NOT pull the cable taught!
• Account for the lazy “S” shapes when calculating your run length; Add one foot per “S” shape.

To make digging a trench more efficient, a trencher machine can be rented from the local equipment rental store. Use eye and ear protection.

Always contact your utility companies and request they come out and mark where your utilities are located BEFORE you dig.

Rodent warning! If you have a mole problem, you are well advised to use conduit instead of directly burying your cable.

Tips and tricks for installing overhead aerial Ethernet cable

An extremely common method of running Ethernet cable between two structures is to go high. This means to use two or more attachment points and secure the cable out of reach.

Pros:

• Aerial cable installation is potentially less expensive since renting a trenching machine won’t be required.
• Aerial cable runs may be less labor intensive (depending on what you are doing).

Cons:

• Aerial Ethernet cable is unsightly in some environments and your local HOA may object!
• Installation of cabling overhead may require additional knowledge of local building codes, especially if the overhead run will pass over public access areas.
• Given the nature of working up high, the installer is exposed to a much higher degree of fall danger.
• All aerial Ethernet cable runs are much more ESD prone, requiring the use of shielded Ethernet cable and surge protection devices.
• Proper bonding to ground of the cable shield is imperative to allow ESD events to safely drain off to ground as opposed to damaging your expensive network equipment.

Best Practices:

Falls are the leading cause of serious injury and even death at work.  Improper ladder use, training, and lack of the proper safety equipment is dangerous!

• Know your local codes if your overhead run will pass over public access areas, it may be illegal for you to install your cable in this fashion!
• If you do not own what you are attaching your Ethernet cable to, or don’t have explicit permission to attach to something you don’t own, then don’t attach to it.  You may incur civil fines and penalties for attaching your cable to something you should not.
• Always have a second person on hand when working up high, even if they are just observing, in case of an emergency.
• DO NOT work near high voltage power lines, feeder lines, or transformers unless you have the specialized equipment and training to do so.
• If using a ladder, observe all safety precautions for ladder use as falls from ladders are the source of many injuries every year.
• Use shielded Ethernet cable for all outdoor aerial runs between multiple attachment points.
• Properly bond your cable shields to ground by using shielded hardware.
• Mitigate your ESD risks by using surge protectors, and they must be properly bonded to ground as well.
• DO NOT use nylon ties (commonly known as zip ties) to bundle cables together or attach them to a messenger wire. Nylon ties focus excessive pressure in a small area that will cause long term degradation to your transmission performance.  Use UV resistant hook and loop (Velcro) straps instead.
• You may pre-install a stainless steel wire rope and use that as the supporting messenger wire to attach your cable to, or you may also use Ethernet cable that has a messenger wire already attached. trueCABLE sells such a cable, our Cat6 Outdoor Ethernet Cable W/Messenger｜Shielded.

Please see this basic overview video on a simplistic Ethernet cable with messenger wire installation: Cat6 Shielded Aerial Messenger Cable: Up The Ladder You Go!

For more detail and guidance, including attachment point hardware and methods, please see Outdoor Ethernet Messenger Wire Support Interval : A Pole Too Far?

Ethernet cable that passes within proximity to transformers and feeder circuits is subject to extreme levels of EMI. Please see Top 2 Things to Consider When Running Ethernet and Power Cable.

Please see When Lightning Strikes! Ethernet Data Cable and Lightning Protection for more information on ESD protection.

Tips and tricks for same structure outdoor Ethernet install

Most homeowners and DIY’s will experience this type of outdoor installation. Typically, outdoor mounted surveillance cameras are installed in this fashion. Everything is mounted to the same structure, so there is no risk of ground loops and only minimal risk of lightning-induced ESD events.

Pros:

• This is the least labor intensive type of outdoor Ethernet installation.
• Same-structure outdoor Ethernet installations are the least expensive as the mounting hardware is typically very easy to get and not pricey.
• The biggest advantage of same-structure outdoor Ethernet installations is allowance  for use of easy to deal with unshielded outdoor Ethernet cable.

Cons:

• Unsightly unless the cable is hidden inside soffits, etc. May require picking a specific cable color.

Best Practices:

• Attach the cable to your structure with screw-in outdoor grade RG6 coaxial cable clamps. These clamps are easily picked up at Home Depot or Lowes. If there is more than one cable running together, bundle the cables with hook and loop straps every 3 to 5 feet.
• DO NOT use nylon ties (commonly known as zip ties). Nylon ties focus excessive pressure in a small area that will cause long term degradation to your transmission performance.

So, there you have it! A comprehensive explanation of how to deal with outdoor Ethernet cable installation. One of the most rewarding aspects of running Ethernet cable outside is seeing it all come together, but understanding the ins and outs of outdoor Ethernet cable requires planning and research. With that I will say…

HAPPY NETWORKING!

trueCABLE presents the information on our website, including the “Cable Academy” blog and live chat support, as a service to our customers and other visitors to our website subject to our website terms and conditions. While the information on this website is about data networking and electrical issues, it is not professional advice and any reliance on such material is at your own risk.