How To Properly Patch and Repair Your Network Cables

By Jason Imms

We're going to help you to become "that guy" who can fix network cables.

Network cables are the arteries and veins of the Internet. A cabled network is the most reliable of the available options for setting up network infrastructure as it provides the highest speeds, is less prone to failure and has fewer points of failure to check during troubleshooting. Being less prone to failure, though, does not make it foolproof. Cables get twisted, caught in doors, have clips broken and become unreliable as they’re pulled and tied in knots during transport.

Today, we're going to help you to become "that guy" who can fix network cables. Y’know, the guy who brings a roll of bare Ethernet cable, a crimping tool and a bag of 8P8C plugs to every single LAN, just in case. We’re here to tell you, that guy is awesome.

Cable Type: The Choice is Yours

Whether you choose to use Cat5e or Cat6 cable is entirely up to you and your budget. If you can get Cat6 for a reasonable price then there is no reason not to as it is the superior option. That said, unless you’re making cables that will be installed into your home on a permanent basis there is little need to bother with Cat6 at this point in time. The advantages that it provides won’t be utilized by consumer grade networking gear any time soon, until home networks achieve speeds greater than 1 Gbit/s. This guide below will focus on Cat5e.

An Anatomy Lesson

To the naked eye, the anatomy of the different cables does not significantly differ between categories, though each can be identified by the text printed along the length of the cable. The major differences are found in the shielding and how tightly the wire pairs are twisted. A Cat6 cable is better able to avoid crosstalk and provide faster speeds than the Cat5 variants thanks to it’s heavier wire shielding and tighter pair twists. This makes our job easier, as it means that the guide below will be applicable no matter your chosen cable standard.

A Cat5e cable is made up of four twisted pairs of wires, each independently color shielded. These wires terminate at 8P8C jack plugs, or RJ45s as they’re more commonly (albeit mistakenly) known. As it turns out, “RJ45” refers to the 8P8C male plug and female socket in conjunction with the a common telephony wiring standard. The vast majority of network cables that we encounter use 8P8C jacks and sockets, and the T568A or T568B wiring standard. That said, “RJ45” is used colloquially often enough that perpetuating the misconception in conversation is unlikely to result in ridicule.

The 8P8C modular connector is a molded plastic jack plug with eight raised, gold-colored pins at one end, and a crimp tooth at the other. The plug is a solder-less design, meaning that each individual wiring job is relatively quick and easy, but will require the acquisition of a specialized tool. A crimping tool is used both to firmly attach the plug to the cable, and to make contact between the pins on the plug and the wires inside their colored shielding. Two types of 8P8C connector exist to suit both stranded, and the less common solid Ethernet cable. Both will work with any available crimping tool, but be sure to purchase the correct connector for your cable type to guarantee a reliable electrical connection.

Wiring Standards

Whether you choose to use the T568A or B wiring standard is up to you. T568B is more commonly used in the US, while Canada and Australia favor T568A. Both standards require a single cable to be at most 100 meters in length. The only major difference between the two that concerns us is the reversed position of the green and orange wires. For the purposes of non-installation home networking, the choice is largely irrelevant as long as you make sure to use the same standard at each end of a single cable. Note that if you choose to have cables installed in the walls of your home, government regulations on standards choice may apply. The photos below use the T568A standard. For reference, the numbers in the diagram correspond with the pins on the 8P8C modular connector, left to right when the locking clip is facing away from you.

The Tools You’ll Need

A length of Cat5e cable, a crimping tool with cable stripper/cutter, 8P8C jacks (more than two - mistakes happen), plug boots, cable tester. All of these tools should be available at your local electronics parts and spare store, or Amazon.

The Repair Process

Choose and cut your desired length of cable. Remember to allow a little extra for mistakes.

If you have them, add the plug boots to your cable now. Once an 8P8C jack has been crimped to a cable it cannot be temporarily removed, only cut off and replaced.

Strip the outer shielding from the cable, roughly 1.5 centimeters. Most crimping tools have guides which will help to expose the correct length of wire. Check the eight exposed wires to ensure that you didn’t inadvertently expose the copper within. If this occurs, simply cut and strip again.

Some network cables have a length of fibers running through them to help to strengthen the cable and bulk out the core. Cut these away with a pair of scissors or a sharp knife.

Reorder the wires according to the desired wiring scheme. This can be a fiddly and troublesome task thanks to the fact that the eight wires are divided into four twisted pairs. Do what you can to end up with a flat group of wires without any tangling.

Because you have untwisted the pairs, you’ll notice that the wires are no longer even lengths. Trim to remedy this situation, as it is imperative that each wire is of an even length to ensure a solid connection.

Straighten all of the lengths of wire and line them up in the correct order. Hold them tightly between your finger and thumb ready for insertion into the plug.

Each wire should easily slide into their designated slots in the plug. Double check that you have maintained the correct order during this process. Each of the wires should reach the far wall of the plug in order to be pierced by each of the teeth on the pins.

Triple check your wiring order and that there is a good amount of blue shielding underneath the crimping crimp. It is worth making these checks because once a plug has been crimped onto cable, it can’t be removed and reused.

Insert the plug into the correct slot on the crimping tool. Ensure that you have inserted it into the correct side of the tool - the teeth on the tool should correspond with the pins on the plug.

When you’re sure that everything is in the right place, go ahead and crimp. Press the plug firmly into the socket on the crimping tool and squeeze the handles together. Two or three squeezes should ensure a firm crimp. You’ll notice that the raised pins have been pushed down so that their teeth pierce the wire shielding and make contact with the copper within.

Slide the plug boots up so that they cover the clips and you’re finished! All that is left to do is confirm that your cable works by using a cable tester, or by simply attempting normal use of the cable.

Now that you have the knowledge and tools necessary for performing network cable repairs, it might be time to have a look over the cables that you currently have in use around your network. Replace any jacks with broken locking clips, frayed shielding or cracks in their housing. Eliminating doubt about the state of your physical network infrastructure will leave you free to troubleshoot problems from the comfort of your office chair, rather than crawling around on hands and knees confirming that all of your cables are in place.