How to Terminate RJ45 Connectors on Cat 5e, Cat 6, and Cat 6A Cable

For many people, the process of terminating an RJ45 connector is a daunting one. The parts and pieces are delicate, and if put together incorrectly, can either operate poorly or not work at all. For example, the first time that I had the opportunity to work with any kind of 8P8C connector I tried to teach myself how to do it. I spent several hours slowly struggling to put together only a hand full of connectors. Small things that seemed trivial at the time led to many of the terminations needing to be completely replaced. The thing I remember most about that day is how it only took a few minutes of advice from a more experienced installer to transform my confused process into an effective workflow.  

In this article, I will attempt to replicate the success that my colleague provided for me when he discovered me struggling to learn to terminate RJ45 connectors on my own. He first showed me a step-by-step workflow that he used when terminating using RJ45 connectors. Then he took the time to show me some of the most common mistakes that can cause problems with this kind of termination. 

While terminating an RJ45 connector can be an intimidating task anyone can quickly learn everything that they need to know about the process simply by following the instructions and advice of someone who has been doing it a long time. In the remainder of this article, you will find the advice that was given to me more than a decade ago along with some little nuggets of information I have found since then. I hope that the information is as useful to you as it was for me. 

If you are looking for a guide on how to terminate Ethernet Jacks rather then RJ45 connectors my article on the subject can be found here.

Choosing the Best RJ45 Connector for your Project 

The very first question that needs to be answered when preparing to terminate an RJ45 connector is what style of RJ45 connector will be used in your project. I have written an entire post on the pros and cons of the various styles of connectors for those who would like more information on this subject.  If you are just looking for a recommendation for a decent quality connector from a manufacturer with great quality control these connectors from Klein are a good place to start.

The bare minimum that you need to know before you get started terminating is that not all RJ45’s have the same rating or even feature set. You should make sure to use connectors that have the same rating as the cable that you will be attaching them to. The first reason for this is that not all wires inside Ethernet cables are the same diameter. For example, a cat 5e cable is normally a 24 AWG while a cat 6 cable is often a 23 AWG. This means that the wires inside of a cat 6 cable are often over 10% thicker than the wires in an older cable. Because of this, a cat 5e rated RJ45 connector may not even fit on the end of a cat 6 cable. 

The second reason that this is important is that a connector of a lower rating is not guaranteed to work at the same performance level of the cable that it is attached to unless it also has the same rating. You can be sure that everything will fit together correctly and work as intended by making sure that your cable and connector have the same category rating. 

The last bit of advice that I have on this subject is that I do not recommend using connectors that do not come with some kind of dust cover, or boot, to protect the termination. 

Terminating RJ45 Connectors, A Step By Step Guide 

Step 1: Install The Boot 

An often overlooked step to terminating an RJ45 connector is the installation of the boot. You have to do this before anything else and if you forget it you will need to cut off your work and completely start from the beginning. I have been working with Ethernet for years and I still forget this step from time to time. 

To install the boot, simply slide the boot over the end of the Ethernet cable. 

Step 2: Stripping the Cable Jacket 

In this step, we will be removing all of the pieces of the Ethernet cable that will not be inserted into the jack itself. The outer jacket will be removed first. Then all of the rest of the inner components other than the eight colored wires (and the grounding conductor in the case of shielded cable) will need to be taken out. Some cables will only have the jacket while others will have quite a bit of extra material that will need to be removed. 

There are quite a few different options out there for stripping cable. Whatever tool you chose to use, the important thing to look out for is damage to the plastic coating of the inner wires. While a small scratch on one or two of the conductor’s jackets may not seem like a big deal, this small defect can cause the entire cable to not work properly. Make sure to take a moment after stripping the outer jacket to insure that the inner wires are still flawless.  The small knick in the   image below is more then enough to cause a cable to fail. If you have anything like this just cut it off and try again.

Some tools are more prone to damaging the inner conductors than others. For example, cable strippers generally work well and I tend to trust them after terminating just a few cables on a new job. On the other hand, stripping back jackets using scissors or a knife is much more variable and I inspect every single cable before moving on if I am using a more manual tool like this. 

If you can find a pair of the strippers that I used in this example they are great! The major drawback is that they are designed to be used with plenum grade cat 6E cable like the stuff I used in this example and will not cut perfectly on any other kind of cable. If you are only going to own one pair of strippers I actually recommend this pair. I own them as well and they work just as flawlessly as the Kleins in the example photos. Additionally they can be adjusted to work well with any Ethernet cable that you are terminating.

I recommend that people strip away at least two inches of the jacket when they are first starting to learn. This amount can be reduced later on as you get more confident and I strip back about an inch and a quarter when I am terminating. Exposing more wire may make the next step take a bit longer but it makes the whole process much easier. 

After the jacket has been removed. Cut out any material that is not one of the eight colored wires or a grounding element in the case of a shielded connector using a pair of wire snips. These grounding elements may be a bare wire, a foil shield, or both. These shielding conductors should be folded over the jacket and out of the way where they will be squeezed into the metal part of a shielded connector at the crimping stage of the termination process. Though it is not completely necessary, I also like to trim back the shielded elements at this stage. They should be long enough to where they just barely peek out of the back of the connector when fully assembled. 

Some cables do not have anything else to remove while others do. Some of the things that you may need to remove depending on your cable are the following; 

  •  Water Proof Gel (Sometimes called Icky Pick)
  • Kevlar thread
  • Plastic or paper separators
  • Foil jacket (when not part of a shielding system with a shielded connector) 

Once you are left with nothing but the conductive elements of the cable you are ready to move on to the next step. 

Step 3: Order the Wires by Color Code 

Next, we will be organizing the wires so that they will be in the proper order when they are placed into the connector later. Before we can do this we need to decide what order, or color code, we are going to follow. 

The most important things here are that you use one of the standard color codes defined by TIA/EIA 568A or TIA/EIA 568B and that the terminations on both ends of the cable use the same color code. Because of this, I recommend that you follow the same standard that is already in use on your project if there is one. If you are terminating the first cables on the project and get to choose which of the color codes you would like to follow I usually recommend using TIA/EIA 568B. 

If you are curious as to why that is my recommendation or would like to learn more take a look at my article on the subject. 

  When talking about color code in RJ45 connectors, always start from left to right with the clip of the connector facing away from you.

Pin NumberWire Color
Pin NumberWire Color

Now that we know what color code you will be using to terminate your cables we can move on to bending the wires into position. The above pictures show what the end of your cable should look like after you are finished with this. 

The three major mistakes that people make when performing this step all have to do with how the cables are manipulated into the fan shape. The first mistake that I see from time to time is when someone lets wires cross each other more than necessary. Every time that a wire crosses over one that is not its pair is an opportunity for the signal to leak from one wire to the other. This should be avoided whenever possible. 

The only time I can think of offhand where you will need to cross wires on top of each other is when you are using the TIA/EIA 568A color code. In this situation, you will need to pass the orange wire behind both of the blue wires to make them line up correctly. 

The other two mistakes that people often make when sorting the wires for termination are a bit more common and similar. They are either untwisting more wire than necessary or twisting the wire tighter than it is when it comes from the factory to make it fit. Both of these situations can cause a condition known as cross talk and will reduce the performance of the cable. 

The goal here is to transition as smoothly as possible from twisted pairs of wires into a connector. To do this you should remove the wire twist completely whenever you need to so that it will fit together smoothly but no more than that. 

Step 4: Straighten Out The Wires 

This may seem like a simple and silly thing to dwell on but when people don’t take enough time to get the wires in a termination perfectly straight it causes more problems for them down the road than almost anything else. The goal here is to get the wires perfectly straight as close to the jacket as we can without messing up any of the twists in the wires. 

Don’t worry too much about straightening out the ends of the wires here. They will just be trimmed off in the next step. Focus instead on ensuring that the inch or so of wire closest to the jacket is as straight as you can get it. 

The best way that I have found to do this is to tightly pinch the end of the cable jacket down onto the wires with my left hand and do all of the straightening with my right. This keeps the wires from moving around and getting out of order. You can pull the wires straight against a knuckle on your right hand but I find that pulling them against the hard edge of a tool works even better. 

Some connectors come with small plastic inserts or sleds while most do not. If your connectors require one of these inserts now is the time to install it. I avoid these types of connectors when I can as they slow down the process once you get confident enough to terminate reliably without them. 

Now that the wires are all nice and straight, and have their inserts installed if needed, take a moment to make sure that they are all still in the proper order then move on to the next step. 

Step 5: Trim the Wires to Length 

Up until this point, the termination process has been the same no matter what style of connector you are using. From here things differ a bit if you have opted for EZRJ45 connectors. If you are using this type of connector simply trim up the end of your wires so that there is nothing left but perfectly straight wires. Make sure there is still plenty of wire left to go completely through and out of the front of the connector. 

Those of us who prefer to use the standard style of RJ45 will be trimming back the wires to their final length in this step. After a few terminations, you will get a good idea of how long to trim the wires but for now, it is best to hold the connector up next to the wires before you trim them so that you can see exactly how long that they need to be. 

When the wires are at their final length they should be long enough to reach completely into the connector and touch the inside of the front. The outer jacket of the cable needs to be far enough forward to reach past the point in the connecter that will crimp down and hold it into place later. 

Before actually trimming the wires pinch down on the jacket and wires where they meet to ensure that they do not move around during the trimming or before the wires are fully inserted into the connector. Take care to not let go of the wires until they are fed into the connector. In many cases, the wires will move quite a bit after trimming if you are not careful. 

Step 6: Insert the Wires into the Connector 

To insert the wires into the connector first hold up the connector in your freehand with the clip facing away from you. Next line up the wires at the bottom of the connecter. Make one last check to make sure that all the wires are in the proper order with wire number one on the left side and wire number eight on the right. 

Place the tips of the wires inside of the connector and gently press the wires against the inside of the clip side of the connector as they slide in. By forcing the wires to ride against the back wall of the connector you increase the chances that everything will line up the way you want. By the time the connector hits the hand that is pinching all of the wires together everything should be far enough in to allow you to let go without the wires losing their positioning. 

From here all you need to do is let go of the wires with your fingers and slide the connector as far onto the wires as it will go. Because you took the time to prepare everything properly this step should go together cleanly and easily. If wires bunch up in the connector or jump out of position go back and make sure everything is getting lined up properly earlier in the process. 

If you are using an EZRJ45 connector the wires will go completely through the connector and come out the front of it at this point. This step is made a bit easier by this type of connector because you can then grab the end of the wires and give them a little tug to make sure everything is tight. 

Step 7: Install the Boot 

There are two major styles of boots that are designed to protect RJ45 terminations. Depending on the style you will either need to install it now or at the end of the termination process after the connector is crimped and inspected. I prefer to use the style of boot that goes inside of the connector and gets permanently crimped into place. 

If you have a connector with this style of boot you will need to slide it up and into the boot now. When you do so just be careful not to let any of the wires move out of position. It does not matter how tightly the boot is seated into place but if a wire slides out even a little bit performance of the connector can be affected. 

The boot that goes with the connector in the pictures on this article features the other style of boot. With this boot, you need to finish the termination all of the way and then slide the boot on at the very end. This boot is not my favorite because it is not permanent and provides less strain relief for the cable as it goes into the connector but it is what I have left over from what was ordered by the last company I did a job for so here it is. 

Step 8: Crimping the RJ45 Connector 

Crimping the connector is probably the easiest part of the entire process. Most crimping tools have several different spaces where you can insert a connector. Look for the space labeled 8P. This stands for eight positions and means that connectors with room for eight wires should be terminated using that slot. The opening is keyed for the clip so you should be able to see what direction to insert the connecter. 

Slide the connector in all of the way until it will not go in any further and then ensure that everything is still firmly held together before squeezing the tool. Most crimpers have a ratcheting system so you will hear a series of clicks as the tool closes and it will not open back up until the connecter is all the way terminated. 

If you are using EZRJ45 connectors and you have the correct crimpers to go along with them all of the wires will be automatically trimmed off during this step. If you do not have the correct crimpers then you will be left with a fully terminated jack with wires hanging out of the front. You will need to use a knife to trim back the wires flush with the front of the connecter before you will be able to use the cable. Below are a couple of good crimpers that I can recommend. The pair on the left are my go to crimpers and the ones that I used in this example. The ones on the right are a bit more expensive but will automatically trim the wires back on an EZ RJ45 connector.

Shielded connectors have a few different styles and most require that you use the correct style of crimpers for everything to work properly. Assuming you have the correct tool for the job The metal part of the connector will be crimped onto the shielded parts of the cable during the crimping process. Some connectors also have a second section that also needs to be crimped before the shielded elements are completely terminated.   

Step 9: Inspection 

The last step to terminating an RJ45 connector is to inspect the connecter to make sure that everything has lined up properly. Make sure that; 

  • No wires have moved out of position and the color code is still in place 
  • All of the wires are completely inserted and are touching the front of the connector 
  • All of the pins are pressed completely up and into the wires 
  • The cable jacket is firmly crimped into place 
  • The boot is firmly crimped into place if your boot is this style 
  • Nothing gives when you gently tug on the connector 
  • No plastic elements are chipped or cracked 
  • If you are using an EZRJ45 connector make sure that all of the wires are cleanly trimmed back and flush with the connector 

If everything looks as it should slide the boot into place if you are using that style of connector and the cable is now ready to be tested and used.