How To: Install Copper Ethernet and Coaxial Cable for Success

Written by Don Schultz, trueCABLE Senior Technical Advisor, Fluke Networks Copper/Fiber CCTT, BICSI INST1, INSTC, INSTF Certified

The most expensive cable in the world, per foot, is the one that is 1” too short. Did you know the vast majority of Ethernet cable is ruined due to poor installation practices? This is not a judgment on anyone, it is simply the average “Joe” is not an experienced installer of Structured Cabling Systems and likely did not have the benefit of going through formal training. Even fewer people have had the benefit of going through a BICSI INSTC course. Poor termination practices are yet another significant source of installation issues, which trueCABLE has extensively addressed in our Cable Academy. We won’t be discussing best practices around Ethernet and coaxial cable termination here, but instead will cover physically installing the cable.

What We Will Cover

• Calculating run (drop) length for copper twisted pair Ethernet cable
• Calculating run (drop) length for coaxial Series 6 (aka RG6) cable
• Pulling guidelines
• The importance of cable lubrication
• Temperature induced Insertion Loss as it relates to permitted length for Ethernet twisted pair cable
• Obeying the bend radius specification for your particular cable
• The importance of proper labeling

In short, we are going to get back to the basics and explain how to get your cable installed without damaging it or going over length!

Calculating Run (Drop) Length for Copper Twisted Pair Ethernet Cable

This section addresses Cat5e, Cat6, and Cat6A (Cat8 being a different discussion) Category cable. The maximum lengths are the same regardless of Category, as long as the conductors are solid copper and from 22 to 24AWG.

Many people are unaware of some rules around maximum cable length, or have been victimized by (well intentioned) misinformation. Before we can even talk about calculating, you need to understand what your limits are to help in decision making. To understand what the proper run length maximum looks like, we have to discuss the differences and similarities between permanent links and channels, which are terms you are likely not familiar with.

• Permanent link. A permanent link is the permanently installed part of your overall communications channel. Typically, it is composed of the solid copper Ethernet portion of the installation and is terminated from patch panel to outlet, yielding a female port on either side to patch into with patch cords. You pull the permanent link into place, terminate it, and then plug in patch cords to get your channel. The permanent link part of the channel is what we want to calculate for purposes of this section.

• Channel. A channel is the entire end to end communications channel from switch to device, or switch to switch. This will include the permanent link above, plus any necessary patch cords to complete the connection. Channels always end up in 8P8C (aka RJ45) connectors on the very ends. We won’t be discussing how to figure out how long your channels can be in this blog. If you want to know how to do that, please see Calculating Ethernet Cable Overall Channel Length for Success.

An overall channel, consisting of a permanent link and two patch cords. This concept is foundational to a structured cabling system.

So, how long can each one be? Well, there are a lot of factors to consider. That “328 foot maximum” number you have likely heard about is very misleading. 328 feet is the maximum length of the channel, under ideal conditions, when using solid copper Ethernet and two 24AWG stranded copper patch cords plugged in to complete the connection at both sides.

The maximum permitted length of the permanent link is 295 feet, under ideal conditions and caveats, to permit the use of patch cords. Given 328 - 295 is 33 feet or so, you are limited in this scenario to a total of 33 feet in patch cord. Given ideal conditions. The whole “ideal conditions” term comes up a lot, doesn’t it? Well, take a look at Calculating Ethernet Cable Overall Channel Length for Success and then come back here!

Now that you understand what part of the run we are talking about, which is the permanent link, we can actually start calculating that! You know you are starting at 295 feet as your maximum, before ambient temperature is taken into account, right?

Since each installation is different, the permanent link run length and the various methods used to calculate it are going to vary. A measuring wheel is an excellent tool, and inexpensive. Here are some best practices:

• Calculate all vertical and horizontal routes the cable will take using the best tool to get measurements (measuring wheel being an excellent choice.)
• Add one foot for each turn the cable takes to account for bends.
• Add two feet at each outlet for service slack and termination.
• Add 10 feet** for service slack and termination at the “head end” or consolidation point of your runs (like at a patch panel/switch) for residential installations. The ten foot value is based upon a typical 36” tall multimedia enclosure, plus service slack stored above or inside the enclosure.
• For commercial installations, add what it takes for the cable to reach the opposite wall from where it enters the TR, in addition to floor to ceiling height. This is typically 24 feet** in a commonly sized floor serving TR. This 24 foot** value takes into account terminations plus service slack stored on ladder racking or a wall.

Residential formula: 10ft** + all vertical and horizontal distances outside of enclosure + 1ft for every turn + 2ft for termination at the remote outlet. Then add 5% to the total you get for measurement mistakes.

Commercial formula: 24ft** (typical TR) + all vertical and horizontal distances outside of TR + 1ft for every turn + 2ft for termination at the remote outlet. Then add 5% to the total you get for measurement mistakes.

** Service slack at the consolidation point of your installation must be factored in along with potential Insertion Loss your cable may experience due to elevated temperature environments. It is permissible to reduce the service slack if the cable will be overlength for temperature. See below for more information.

Important: To minimize cable on cable interference when using U/UTP Ethernet cable, store all service slack in a figure “8” pattern while obeying the minimum bend radius guidelines for the cable you are working with. Shielded Ethernet may be stored in a circular pattern if so desired. Use nylon hook and loop straps to secure the cable into the desired pattern.

Permanent cable runs in a figure “8” pattern to store service slack

Calculating Run (Drop) Length for Coaxial Series 6 (aka RG6) Cable

Coaxial Series 6 cable drops and patch cords are subject to significantly different rules for length, and it drastically varies depending upon the application. Series 6 coaxial cable is a jack of many trades, but only a master of one or two. It is not used for Ethernet packet signaling much anymore since it is very slow for this task, but it is used for cable TV (CATV) and satellite systems quite a bit--referred to as “broadband”. So, considering the length rules are the same for those two applications that is what we will talk about here. Coaxial broadband cable may be installed with similar star topology to copper twisted pair Ethernet or it may also be installed in a “bus configuration". Which configuration you are using will depend on what your environment is. Therefore it is hard to make generalizations about channel length as the channel may also include signal boosters, filters, and traps. Here is something a bit more concrete: Maximum supportable broadband distance, including the horizontal permanent cable and any necessary patch cords, is 184 feet for Series 6 coaxial cable.

• Horizontal cable. Essentially, the horizontal cable is the cable that runs from a main or secondary connector point to the equipment outlets. The equipment outlets are usually female threaded F-connector style, although BNC is also permitted. The maximum length for any single segment of broadband cable applications is 150 feet from the booster/splitter/main connector directly to the outlet.

• Cord cable (patch cords). You may have up to 33.5 feet total of Series 6 (aka RG6) patch cable from the outlet to your equipment (TV, cable box, etc.).

Considering coaxial cable is subject to much more restrictive length maximums for broadband applications, leave 18 to 24 inches of service slack on both sides to ensure the ability to accommodate termination. If you can store more service slack at the main connection/consolidation point then please do so, but keep in mind the length limitations you are working with. There is no need to use a figure “8” pattern for coaxial service slack storage, as all coaxial cable is shielded by design.

Cable Pull Guidelines

The vast majority of copper twisted pair Ethernet and coaxial communications cable is damaged during the installation process! If you follow some basic guidelines, you will have an easy installation without cable damage.

Pulling Tension Maximum

25 ft-lbs is the maximum amount of pulling force that should be applied when pulling solid copper Ethernet cable. 40 ft-lbs is the maximum pull force permitted with solid copper coaxial Series 6 cable. Copper clad steel coaxial has a 75 ft-lb maximum pull force. Force exceeding this should be avoided as it may damage the cable jacket or conductor(s), degrading performance. If you feel a large amount of resistance or a “hard stop” then cease pulling and investigate. If yanking has to be part of the installation process, something is seriously wrong. It is easy to exceed the permitted pull tension and damage your cable this way!

Cable Lubrication

When pulling cable through more than 50 feet of cable tray, basket tray, or through any length of conduit a high quality synthetic wax based lubricant should be liberally applied to the cable jacket at the feed end. Cable lubricants dramatically reduce friction and the risk of damage due to excessive pull force, especially on longer runs and larger bundles. trueCABLE supplies such a cable lubricant.

Installation into 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.

• 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.
• Never use conduit less than ¾” trade size.
• Always use synthetic wax based cable lubricant when pulling through conduit, applied at the feed end liberally.
• Conduit should be rigid, not flexible, as cable jacket damage may result
• 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. Below is a mesh sock with pull-eye.

Redraw above. Make the cable tc blue, the mesh part of the sock can be black. The plastic cap should be black and the wire braided rope should be silver.

How to Attach Pull String for Single or Multiple Runs

Attach a pull string using a minimum of three half-hitches and then secure the knot with electrical tape. For multiple runs, stagger the cable ends as shown.

Attachment at Periodic Points

Many times installations require cable installation using periodic support points as opposed to cable tray and conduit. Residential installations are a likely environment for this type of attachment method. Unfortunately, due to the confluence of less experienced DIY installers and the higher likelihood of cable damage issues resulting from such a strategy we would recommend you follow these guidelines:

• Never pull cable through attachment points as if it was conduit or cable tray. Cable must be placed into each attachment point manually.
• Use J-hooks or bridle rings with saddles. Install the hanging hardware so the cable is supported at three to five foot intervals. Exceeding five feet will allow gravity to damage the cable jacket over time!
• Never use metallic staples (like used for romex).
• Never use plain bridle bridle rings (or similar thin supporting objects).
• Use of nylon ties to bundle cable should be avoided. Nylon ties focus too much force into a small area. Use of nylon hook and loop straps is strongly recommended.
• You may use plastic coaxial cable clamps every three feet. This is typically to secure a singular run. That said, you may attach up to four additional subsequent runs using the first run as an “anchor run”. Attach subsequent runs every three feet using Velcro hook and loop straps. Do not exceed five total runs secured in this fashion.

Temperature Induced Ethernet Cable Length Limitations

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? What the heck could be going on to cause that? Well, temperature affects copper communications cable in a very significant way. Essentially, as copper heats up it becomes more resistant to passing signals. Weird, right? No, not really. It is simply physics. Here is how to avoid the issue:

• 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.

Advice: 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 130℉. Yes, it is getting hotter each year and you probably should take this into account.

Bend Radius Guidelines

To maximize performance and minimize the possibility of cable jacket damage there are guidelines around how much you can bend communications cable, and it differs between copper twisted pair Category Ethernet and coaxial cable. Generic guidance is found in the ANSI/TIA 568 standard.

Generic TIA Guidance for Bend Radius

• Shielded cable cannot be bent as much, due to the potential for damage to the foil shielding.
• The generic guidance from TIA is the maximum allowable bend radius for unshielded Ethernet is 4X the jacket OD. Multiply the jacket OD x 4 and that gives you the bend radius max. Multiply again by 2 and you get the diameter which may help with visualizing that. For shielded Ethernet, it is 8X the jacket OD. For coaxial (quad or dual shield) it is 10X the jacket OD.

However, the manufacturer may have guidelines that override the generic TIA guidance. In fact, trueCABLE specifies a maximum allowable bend radius for each and every one of our communications cable types as found in Obey the Bend: Bending Radius of Cable. A high level table is found below for quick reference.

trueCABLE Brand Specific Guidance for Bend Radius

The Importance of Proper Labeling in Network Installations

Underestimated and frequently overlooked is labeling. A well executed installation can quickly become a nightmare if you have no idea what cable run is going where. Further, even if you do manage to figure it out without labeling your work, what about the next person that comes to modify, add to, or repair the cabling infrastructure? There are many ways of going about it, and of course ANSI/TIA has quite a bit to say which is found in ANSI/TIA-606-D - Administration Standard for Telecommunications Infrastructure. That document is 114 pages long, and is aimed at commercial cabling systems. TIA divides their recommendations into four classifications (Class 1 through Class 4). The class is based upon the size and complexity of the telecommunications system that you need to document. If you are installing into a commercial space, you are likely working on a contract that will dictate how you should label and document the cabling system. In the absence of a contract dictating how you should go about this it is a good idea to obtain a copy of TIA-606-D and follow the guidelines presented there.

We won’t get that formal here, except to present some basic guidance and common sense best practices:

• Label your cable runs immediately after pulling them into place.
• Label your cable runs at BOTH ends.
• Since your cable runs will be pulled into place prior to dressing and termination, use a fine tip permanent marker to label them within 1 foot of each cut end.
• When trimming excess cable, dressing the cable, and terminating the cable work with one run at time. Upon trimming to the correct length, label the cable again so you don’t lose track of which cable is what and where it should go during the dress and termination phase.
• The final labeling should be a permanently attached adhesive label, clearly written out, as to where it is from and what it is meant for. Do this at both ends.
• It is also a good idea to label the patch cords you are using at both sides of your installation with a permanent label, too.
• Don’t forget to put labels onto your wall plates and patch panels so you know what RJ45 port is what!

Conclusion

So, there you have it. Who would have thought there was so much involved? At first glance, installing Ethernet and coaxial cable looks like simply tossing a wire into place and calling it a day. Well, if you want your communications system to work correctly and be easily worked on and manageable now you know it is a more structured and contemplative approach. Hopefully you have a much better understanding of what to look for and how to successfully pull your cable runs with little to no mayhem befalling you. At the very least, this blog will make you cognizant that communications cable is far more than simple wire! With that said…

HAPPY NETWORKING!!

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