PoE Cable: What Cable Is Required for Power over Ethernet?

Choosing the right PoE cable becomes increasingly important as the amount of power carried over Ethernet increases. Standard Power over Ethernet can operate over common twisted-pair Ethernet cabling, but higher-power PoE+ and PoE++ applications place greater demands on the cable and its copper conductors.

For many modern commercial installations, Cat6 or Cat6A cabling provides a strong foundation for PoE. However, the right choice depends on the PoE power level, cable length, installation environment, bundle size and the requirements of the connected equipment.

What Type of Cable Does PoE Use?

Power over Ethernet uses twisted-pair copper Ethernet cable. Depending on the PoE standard and network requirements, this can include Cat5e, Cat6, Cat6A and higher-category cabling.

The cable carries both network data and electrical power between the Power Sourcing Equipment (PSE), such as a PoE network switch, and the Powered Device (PD). This allows compatible equipment to operate without a separate electrical power connection at the endpoint.

If you’re looking for a broader explanation of the technology, our guide to PoE technology explains how power and data are delivered over the same Ethernet connection.

Can Cat5e Be Used for PoE?

Yes. Cat5e can support standards-based PoE and is commonly found in existing network installations. For lower-power PoE applications, properly installed Cat5e cabling may provide everything the connected equipment requires.

However, whether existing Cat5e should be used for a new higher-power application is a different question. Cable construction, conductor size, bundle size, temperature and the amount of current being carried all become more significant as PoE power increases.

For a new commercial installation expected to support higher-power devices, selecting cabling based only on the minimum category required for Ethernet data may not provide the best long-term infrastructure.

Is Cat6 Better for PoE?

Cat6 is commonly used for modern PoE installations because it provides higher network performance and can offer improved power-delivery characteristics compared with older cabling, depending on the cable construction.

One important factor is the size and quality of the copper conductors. Larger conductors generally have lower electrical resistance, which can reduce power loss and heat. This is particularly useful when PoE connections approach the maximum Ethernet channel length or when many powered cables are installed together.

As discussed in our guide to PoE distance, a standard Ethernet channel can extend up to 100 meters, or 328 feet. Cable resistance becomes an increasingly important consideration as power travels farther through the channel.

What Cable Should Be Used for PoE++?

PoE++ under IEEE 802.3bt can deliver substantially more power than earlier generations of Power over Ethernet. Type 3 can provide up to 60 watts at the PSE, while Type 4 can provide up to 90 watts.

Higher power means higher current through the cable conductors, making cable quality, conductor size and heat management more important. Cat6 and Cat6A are commonly considered for higher-power PoE installations, with Cat6A offering advantages in applications where cable bundles, heat and higher network performance are important considerations.

The appropriate cable should ultimately be selected based on the complete system design rather than category alone. The PoE equipment, connected device, required power, cable length and installation conditions all matter.

For the differences between these power levels, see PoE, PoE+ and PoE++.

Does PoE Cable Need to Be Solid Copper?

For permanent structured cabling, solid copper conductors are generally preferred over copper-clad aluminum (CCA). CCA cable uses an aluminum conductor coated with copper and has higher electrical resistance than solid copper.

Higher resistance can mean greater voltage drop and heat when electrical current is carried over the cable. Those characteristics make conductor material particularly important in PoE applications.

Cable selection should also comply with applicable codes, standards and installation requirements. A cable advertised as a particular Ethernet category should not automatically be assumed to be appropriate for every PoE installation.

Does Cable Size Affect PoE Power Loss?

Yes. Electrical resistance affects how much power is lost between the source and the connected device. Conductor gauge, cable length, material and temperature all influence resistance.

This is why the power supplied by a PoE switch is not necessarily the same as the power available at the device. IEEE PoE standards account for expected cable loss when establishing power levels.

Our PoE power guide explains the difference between power supplied by the PSE and the wattage available to the powered device.

Can PoE Cables Overheat?

Ethernet cabling carrying PoE produces some heat because of electrical resistance. In a single properly designed cable run, this is generally manageable. Heat becomes a greater design consideration when many higher-power PoE cables are grouped into large bundles.

Cable category, conductor size, bundle size, ambient temperature and installation method can all affect heat buildup. Higher-power installations should therefore consider both network performance and electrical characteristics when cabling is specified.

This is particularly relevant as buildings use Ethernet to power larger numbers of connected devices rather than only traditional network endpoints.

What Is the Best PoE Cable for an Intelligent Building?

There isn’t one PoE cable that is automatically best for every building. For new intelligent-building infrastructure, however, it often makes sense to specify cabling with enough capacity for both current devices and higher-power applications that may be added later.

The decision should account for required PoE power, network speed, distance, cable bundles and environmental conditions. Cabling is a long-lived part of a building, while connected devices and network equipment may be replaced several times during the life of the installation.

That makes proper PoE cabling an infrastructure decision, not simply a question of finding a cable that can power today’s device.