Can Ethernet Cables Go Bad?

Ethernet Cables Go Bad title page

Ethernet cables are a critical part of your home network. They enable fast and reliable connections between your devices. They can also play a large role in your home’s connection to the internet. If you’re not careful when selecting cables for your home network, they can limit the internet speed for all the devices.

Despite how important ethernet cables are, they’re often overlooked and poorly treated.

What many people don’t realize is that ethernet cables can go bad if they aren’t taken care of.

In fact, there are many different ways an ethernet cable can fail. Some common causes for ethernet cable failure include:

  • A bent, cut, or damaged cable
  • Improper connecting/disconnecting of the cable
  • Poor manufacturing
  • Exposure to ultraviolet (UV) rays and harsh conditions
  • Long periods of tension on the cable

In this post, I’ll detail all the common causes of ethernet cable failure and what you can do to prevent your cables from going bad.

Symptoms of a bad ethernet cable

Before we dive into how you can prevent ethernet cables from going bad, let’s start at square one.

How can you tell if an ethernet cable is going bad in the first place?

When an ethernet cable starts to fail, you’ll most likely know about it. That’s because a bad ethernet cable will have a serious impact on your home network.

If you think one of your ethernet cables is going bad, there are a few steps you can take to find out for sure.

Unstable internet connection

One common result of a faulty ethernet cable is an unpredictable internet connection.

As an example, let’s say your ethernet cable is used to connect your internet device to your router.

When looking at your computer or device, it might look like it’s repeatedly connecting and disconnecting from the internet without you doing anything.

You might also find that if the cable is positioned a certain way it’ll have a good connection, but if you move the cable, you’ll lose the connection.

This is troubling because ethernet cable connections are known for their reliability. Especially when an ethernet connection is compared to a wireless (WiFi) connection. This is why an unstable connection is a telltale sign that something might be going on with the cable itself.

No internet connection

The other possible result of a bad ethernet cable is a little more drastic. A failed ethernet cable can result in you losing your internet connection entirely.

Similar to the previous scenario, let’s say your computer is connected to your router with an ethernet cable. You turn on your device, but it says you don’t have an internet connection.

You double check to make sure the cable is securely plugged into your router and your computer, but still no luck.

On top of that, when you look at the lights on your modem and router, everything looks fine.

In this case, your ethernet cable might be the cause of your problems.

There are other reasons why you may have lost your internet connection, but it’s possible that a bad ethernet cable is the cause.

If you think one of your ethernet cables has gone bad, there are some steps you can take to find out if your cable is the reason you don’t have a good connection.

What causes an ethernet cable to go bad?

Now that we know what happens when an ethernet cable fails, let’s dig into why they fail in the first place.

There are many possible reasons why an ethernet cable may stop working. In most cases, either the cables are treated poorly, or the wrong type of cable is used in a given situation.

Let’s break down each of these possible causes.

Causes of ethernet cable failure

The cable is bent, cut, or crushed

This is one of the more common reasons why ethernet cables fail. It’s also one of the most easily avoided.

That’s because it all starts with how well you take care of your cables.

Ethernet cables have twisted pairs of copper wire inside them. There are usually 4 pairs of copper wires, meaning there are 8 copper wires in each cable.

Here are the 8 copper wires inside an ethernet cable after they’ve been untwisted:

Ethernet cable copper wires
Copper wires inside a cat5e ethernet cable

Ethernet cables use the copper wire to transport information from one location to another. If a system at one end of the cable wants to send information to the system on the other end of the cable, it creates a data message for the other system.

This message is translated into electrical pulses, which are sent through the copper wires. When the electrical pulses reach the other end of the cable, the system on that end of the cable translates the electric signals back into the original message from the other system.

That’s the basics of how ethernet cables work.

Now that you know how ethernet cables function, you need to understand what happens if one of these copper wires is damaged.

If something happens to the copper wires inside the cable, the electrical pulses won’t be able to make it from one end of the cable to the other. If the electric signals have trouble traveling through the ethernet cable, it’ll distort the data that’s being sent. When this happens, the connection between the two systems will be lost and the cable won’t work as it should.

When an ethernet cable is bent, cut, or crushed, it increases the chances that the copper wires inside the cable are damaged.

The cable is incorrectly unplugged

Another common cause of ethernet cable failure has to do with how carefully they’re unplugged. This is another case where poor treatment of your cables is usually the root cause.

The difference is that in this situation, we’re more focused on the connectors at the end of the cable.

Ethernet cables have connectors on the end of them that allow you to plug them into computers and other devices. They’re called RJ45 connectors.

I’m sure you’ll recognize this:

RJ45 connector with boot
RJ45 connector on an ethernet cable

RJ45 connectors are important because they connect the 8 copper wires inside the cable to the computer or system they’re plugged in to. There are designated channels within the RJ45 connector that each of the 8 wires is designed to fit in.

If you look closely, you can see there are gold-plated pins of the RJ45 connector.

RJ45 connector pins

As you can imagine, there is one pin for each copper wire in the ethernet cable. As expected, there are 8 pins on the RJ45 connector.

The challenge with this is if one of the 8 copper wires loses its contact with its RJ45 pin, the cable will stop working properly.

This usually happens when an ethernet cable is repeatedly yanked or tugged. Over time, it creates tension on the copper wires in the cable and pulls them away from their RJ45 pins.

For example, yanking an ethernet cable out of your router instead of pressing the tab on the RJ45 connector and carefully removing the cable will result in unnecessary stress on the copper wires inside the cable.

Tension on the cable

It’s not good for your ethernet cable if it’s supporting a device that’s gently pulling on it.

What I’m talking about here is if a device (like your modem) is hanging off the floor and your ethernet cable is what’s holding it up. Even though your modem probably isn’t heavy, gravity will cause it to gently pull on your ethernet cable.

Here’s an example of what I’m talking about:

Tension on ethernet cable
Over time, the suspended modem will create tension on the yellow ethernet cable

Over a long period of time, the hanging modem can stress the copper wires inside the yellow ethernet cable.

Poor manufacturing or quality

This next cause of ethernet cable failure has nothing to do with how you treat them. It actually has everything to do with where you buy them from.

Ethernet cables are used in most homes and businesses. As a result, it seems like everyone is trying to sell them.

The trouble here is that not every manufacturer makes a quality product. There are many knockoff brands and cheaply made cables out there. You need to be careful where you get them from.

When you buy a knockoff ethernet cable, it may not have been made to the same standards that the quality cables are made to. This increases the likelihood that the ethernet cable will fail before it should. In fact, it may even be defective at the time you buy it.

It’s also possible that a good manufacturer will make a faulty cable from time to time. They make so many ethernet cables that they’re bound to have a few bad ones make it out of their manufacturing plants.

This may not seem like a common cause for ethernet cable failure, but I think you’d be surprised. It happens more often than you think.

Ultraviolet light damage and extreme conditions

The last common cause for ethernet cable failure has to do with using the wrong type of cable.

If an ethernet cable is exposed to ultraviolet (UV) light from the sun, it’ll damage the cable. UV light will slowly degrade the plastic sheath on the cable. If the cable is exposed to enough sunlight, it’ll eventually stop working.

UV damage is usually the cause of ethernet cable failure when a regular indoor cable is used outdoors.

Not only is UV light bad for your cables, but harsh conditions are as well. Some examples of harsh conditions include:

  • Extreme temperatures
  • High humidity environments
  • Heavy rainfall or groundwater
  • Moist environments

All these environments will degrade the performance of an ethernet cable over time.

Thankfully, certain types of ethernet cables are designed to work well in poor conditions. You just need to pick the right type of cable depending upon where it’ll be used.

You’ll find out more about this later.

How to prevent ethernet cables from going bad

When it comes to making sure your ethernet cables last a long time, the rules are pretty simple.

First and foremost, you need to make sure you treat your cables the right way. The best thing you can do is put your cables in a position where they don’t need to move and they won’t be tripped on.

Let’s take a look at all the measures you can take.

Make sure the cable isn’t bent at sharp angles

This one is pretty straightforward.

Sharp angles can cause the copper wires inside the cable to bend. This can disrupt the connection between the devices at either end of the cable.

The bottom line is: don’t bend or fold your ethernet cables. Make sure any bends in the cable are gradual.

Gently coil any excess cabling

This method goes hand-in-hand with the previous one. If you have excess ethernet cable, don’t just throw it on the floor in an unorganized mess.

Make sure that any excess cabling is gently coiled. Use cable ties to secure the bundles of excess ethernet cable. Not only will this help protect your cables, but it’ll make your home appear much more organized as well.

Another option here may be to just buy shorter ethernet cables that better fit your home.

Keep heavy items off the cables

This is pretty self-explanatory as well.

Make sure that your ethernet cables aren’t crushed by heavy items like furniture. If your cables are laid under furniture like a couch, make sure the legs of the couch aren’t sitting on top of the cable.

Properly use the RJ45 clips on the cable

When unplugging your ethernet cables from devices, be gentle. Press the lever on the RJ45 clip before removing the cable.

Being rough while unplugging your cables can cause the RJ45 clip to break or the copper wires to pull away from the RJ45 connector. In both cases, it’ll make it more likely that your cable won’t connect to your device’s ethernet ports properly.

Make sure your cable doesn’t have tension on it

Make sure your ethernet cables are connected to devices that’re sitting on top of flat surfaces.

Don’t use your ethernet cables to support hanging devices. This’ll ensure there’s no extra tension on the cable.

Try to buy your cables from quality vendors

This one might easier said than done.

If you can, buy your ethernet cables from companies with good reputations.

This can be especially hard with sites like where there are so many vendors to choose from. Even after looking at the reviews for a cable, it can be hard to tell which cables are the best quality.

You may find that the best method is to try a new vendor each time you need to get an ethernet cable. Once you find a quality cable that lasts you a long time, continue to buy from that vendor.

You may even find that multiple companies make ethernet cables that you like.

Make sure you use the right type of cable

This last method of preserving your ethernet cables is most applicable to outdoor environments. The bottom line is, if you’re going to be using a cable outside, make sure you get a cable that’s designed to do so.

I previously mentioned how UV rays and harsh environments can cause cables to fail. If you need a cable for these situations, don’t get an indoor ethernet cable.

Regular indoor ethernet cables usually aren’t exposed to harsh conditions. As a result, they aren’t made to withstand much abuse.

Waterproof and UV protected cables are made to be much more durable than your typical indoor ethernet cable. That’s because outdoor ethernet cables are waterproof and more resistant to UV rays. If you need an ethernet cable that’ll be used outdoors, grab a cable like this one.

Outdoor ethernet cables are more expensive than indoor ones, but that’s because they’re made of more durable materials. It’s well worth the extra cost to ensure your ethernet cable won’t fail in an outdoor environment.

Wrap up

Hopefully you’re now armed with all the information you need to ensure your ethernet cables last as long as possible. A little prevention goes a long way with ethernet cables. If you treat them properly and use the right cables, they should last you a long time.

If you have any questions about this material, or you’d like to share your experiences with failed ethernet cables, drop a line below.

If you found this information useful, here are some other topics that might interest you:

Does Ethernet Cable Length Affect Network Speed?

How to Tell What Type of Ethernet Cable You Have

Is an Ethernet Cable Faster Than WiFi?

Can an Ethernet Cable Slow Your Internet Speed?

What is an Ethernet Switch Used for?

Ross Ricky

Ross Ricky is an engineer and cybersecurity professional who wants nothing more than for you to get the most out of your home network.

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