What Kind of Cable do I Need for POE?

Power over Ethernet (POE) sends DC current over traditional network cables. You don't need a separate power source for POE devices that include security cameras, signage, routers, and more. POE uses unused or the same pair of wires in an Ethernet cable to deliver electricity. As a result, you have to ensure your cable is able to dissipate heat adequately for improved performance.

Choosing the suitable cable for POE has a few nuances that we are going to explore in our blog. By the end, you will be able to select the right cable for your POE application with ease.

What Type of Cable do You Need for POE?

You don't need to think so much when you are sending data over Ethernet cables. However, you have to consider many factors when you want to deliver power over Ethernet cables. It is important to choose the right cable so that your devices and network are not compromised.

Here are the factors you should keep in mind while choosing a cable for POE:

1.      Conductor and Resistance

Think of the conductor of your cable as a pipe through which you are sending electricity. If the diameter of the pipe (or conductor) is less, you will be able to send less electricity.

Now, if you try to send more power through the small diameter, the cable will start to get heated. This is called resistance and applicable to all electrical applications.

You will need a cable with a big conductor to pass more power without generating heat. In the case of POE, you will need to pick a cable that can handle your POE devices' power requirements.

Find out the POE power requirements of your system. Then choose a cable with the appropriate conductor size.

2.      Cable Temperature

Cables can safely withstand up to a certain level of temperature. The common temperature rating cables support are 90-degree C, 75-degree C, and 60-degree C. So, a cable with a 75-degree C rating will withstand a temperature of maximum 75-degree C safely.

If you cross the temperature, the cable will get heated and degrade in electrical and physical performance. It will also not last as long as other cables.

You should choose a cable with a high-temperature rating for POE. Of course, the power consumption of your POE devices will determine your choice too.

3.      Cable Materials and Construction

Some cables are better prepared to handle POE demands. For example, pure copper cables are a better choice than aluminum cables for improved electrical performance. Cables that have aluminum wires get heated quickly due to higher electrical resistance. Additionally, they can cause issues network issues and hamper your data performance.

Shielding of your cables is another consideration for POE. Shielded cables turn out to dissipate heat much better than unshielded cables. As a result, the former makes a better choice for POE applications.

Moreover, going for metallic or foil shields can be a good decision instead of just rubber shielding.

4.      Cable Length

Cables experience a phenomenon called voltage drop, where power drops as it travels across the wires. The issue can be significant in cables of more than 50 feet. The lost power gets transformed to heat and ends up damaging the cable and performance.

A cable with a big conductor is able to lower voltage drop. In addition, a copper wire and good shielding also contribute to dissipating heat generated due to voltage drop.

5.      Power Consumption of POE Devices

Not all POE devices consume the same power. Therefore, your cable choice will also be influenced by how much power your POE devices use. 

Check the specifications of your POE devices to find out their power consumption. Then pick a cable that can support the wattage of power your devices need. Add the power requirements of all devices connected to your network that you want to power with POE.

Are all Ethernet Cables Suited for POE?

All Ethernet cables have two pairs of twisted wires, and only one is used for data transmission. POE can use the spare pair of twisted wires to deliver DC to your POE devices. It is also possible to transmit electricity using the same pair that sends data. The electricity and data do not interfere with each other or compromise the performance of the cable.

Therefore, all Ethernet cables will be able to support POE applications. However, not all Ethernet cables will be able to handle heat generated by POE or provide the same performance.

A Category 5 cable or CAT 5 cable is the minimum you need to use POE safely. A Cat 5 cable can handle 125volts of current and safely dissipate any heat generated. However, try to go for copper Cat 5 cables with good shielding for the best performance.

Cat 6 and Cat 7 cables are superior to Cat 5 and can support high-power POE devices. These cables have a bigger conductor and higher temperature rating compared to normal Ethernet cables. For example, the best Cat 7 cables can safely withstand temperatures of 90-degree C.

It is necessary to purchase a good quality cable for your POE devices. Cheap cables with poor shielding and non-copper conductor are not safe. They can increase the heat of the cable, hamper performance, and even lead to safety hazards.

As a result, you should never compromise when you pick a cable for POE.

Final Thoughts

Any Ethernet cable can support POE. However, the minimum you should aim for is a Cat 5 cable with good shielding. Cat 5 cables are safe and can help you deliver DC to POE devices without generating too much heat. You can go for Cat 6 or Cat 7 cables if your POE devices demand more power or you're worried about electrical performance. They can also be suitable for applications where you need to send power over a long distance. You can rest assured your cable will not heat up due to voltage drop.

Now, go ahead and choose your POE cable confidently.

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