PoE Ethernet Cable: How to Choose Copper Cabling for Power over Ethernet

PoE Ethernet Cable carries network data and electrical power over the same balanced copper connection. Therefore, one cable can connect and power devices such as wireless access points, IP cameras, VoIP telephones and building-management equipment.

However, selecting cable for Power over Ethernet involves more than choosing Cat5e, Cat 6 or Cat6A. Conductor material, gauge, resistance, channel length, temperature, bundle size and connector quality can all affect performance. Furthermore, higher-power PoE applications place greater electrical and thermal demands on the complete channel.

For equipment and patch-panel connections, RapidConnect Cat 6 Patch Cables provide 24AWG copper conductors, UTP construction, LSZH jackets and performance up to 250 MHz.

What Is a PoE Ethernet Cable?

A PoE Ethernet cable is a balanced twisted-pair copper cable used to carry Ethernet data and compatible Power over Ethernet.

The cable normally contains four twisted conductor pairs. Depending on the PoE type, electrical current may use two pairs or all four pairs. Meanwhile, data continues to travel through the same cabling channel.

A complete PoE connection can include:

• Power-sourcing equipment
• Permanent horizontal cable
• Patch panels
• Telecommunications outlets
• Patch leads
• Connecting hardware
• A powered device

Consequently, PoE performance depends on the complete channel rather than one cable component.

How Does Power over Ethernet Work?

A PoE system normally contains power-sourcing equipment and a powered device.

The power-sourcing equipment, commonly called the PSE, provides power to the channel. For example, a compatible network switch or PoE injector may perform this role.

The powered device, commonly called the PD, receives that power. Typical powered devices include:

• Wireless access points
• IP surveillance cameras
• VoIP telephones
• Access-control equipment
• Intercom systems
• Network sensors
• LED lighting controllers
• Building-automation devices

Before applying full power, compatible equipment uses a detection and classification process. As a result, the PSE can determine whether the connected device supports PoE and how much power it may require.

However, the amount supplied by the PSE is greater than the amount available to the powered device. This difference accounts for permitted losses in the copper channel.

PoE Types and Available Power

IEEE PoE specifications define several power levels.

PoE type	IEEE specification	Maximum PSE output	Maximum power at PD	Powered pairs
Type 1	IEEE 802.3af	15.4 W	12.95 W	Two pairs
Type 2	IEEE 802.3at	30 W	25.5 W	Two pairs
Type 3	IEEE 802.3bt	60 W	51 W	Up to four pairs
Type 4	IEEE 802.3bt	90 W	71.3 W	Four pairs

These figures describe maximum standardised power levels. Nevertheless, the actual power used depends on the PSE, the powered device and their negotiated classification.

Moreover, manufacturers sometimes market products using terms such as PoE, PoE+, PoE++ or 4PPoE. Because those terms can be applied inconsistently, the IEEE type and required device power provide a more reliable basis for selection.

PSE Output Versus Powered-Device Power

A common PoE misunderstanding involves quoting PSE output as the power available to the device.

For example, IEEE 802.3bt Type 4 can provide up to 90 W from the PSE. However, the maximum power available at the powered device is approximately 71.3 W.

This difference occurs because copper conductors and connections have electrical resistance. Therefore, some energy is converted into heat as current travels through the channel.

As cable length and resistance increase, voltage drop also increases. Consequently, the powered device receives less voltage and power than the PSE supplies.

Two-Pair and Four-Pair PoE

Type 1 and Type 2 PoE deliver power through two conductor pairs. In contrast, IEEE 802.3bt introduced four-pair powering for higher-power applications.

Using four pairs distributes the current across more conductors. Therefore, each individual pair can carry less current than a two-pair system delivering an equivalent total power level.

Nevertheless, every conductor and contact must be terminated correctly. A continuity fault, high-resistance contact or excessive resistance unbalance can affect power delivery even if basic Ethernet connectivity appears to work.

Can Cat5e, Cat 6 and Cat6A Carry PoE?

Cat5e, Cat 6 and Cat6A can all carry compatible PoE applications. However, category alone does not determine PoE suitability.

Cable category primarily defines transmission-performance requirements. Meanwhile, PoE performance also depends on electrical and physical characteristics such as:

• Conductor gauge
• Conductor material
• DC resistance
• Resistance unbalance
• Channel length
• Cable temperature
• Bundle size
• Connector construction
• Installation environment

Therefore, it is incorrect to assume that Cat5e is limited to low-power PoE or that Cat6A is always required for IEEE 802.3bt.

Cat 6 often provides a practical balance for new commercial networks because it offers 250 MHz performance and greater transmission headroom than Cat5e. Additionally, many Cat 6 products use conductor sizes that suit common PoE installations.

For more information about its construction and applications, read our Cat 6 Cable guide.

Why Conductor Material Matters

Solid copper conductors are generally preferred for standards-aligned data cabling. Copper-clad aluminium, commonly called CCA, uses an aluminium core with a thin copper coating.

Although CCA cable may appear similar to solid copper cable, aluminium has greater electrical resistance. Consequently, CCA conductors may create more voltage drop and heat.

CCA cables may also have:

• Lower mechanical strength
• Reduced termination reliability
• Greater conductor resistance
• Less predictable PoE performance
• Questionable compliance with project specifications

Therefore, verify the conductor material rather than relying only on the category printed on the jacket.

Conductor Gauge and PoE Performance

American Wire Gauge, or AWG, describes conductor size. A lower AWG number generally indicates a larger conductor.

For example, a 24AWG conductor is larger than a 28AWG conductor. Consequently, the larger conductor will normally have lower resistance when the material and construction are otherwise comparable.

Lower resistance can help reduce:

• Voltage drop
• Power loss
• Cable heating
• Thermal stress within bundles

However, gauge should not be assessed in isolation. Cable length, conductor material, ambient temperature and current load also affect the result.

Moreover, smaller-diameter patch cords are not automatically unsuitable for PoE. Their permitted length and power application must instead follow the product specification and complete channel design.

Solid Versus Stranded PoE Cables

Solid and stranded conductors perform different roles within a structured cabling system.

Stranded conductors

Stranded cable uses multiple fine copper strands within each conductor. As a result, it provides greater flexibility.

Therefore, stranded cable is commonly used for:

• Patch leads
• Switch connections
• Equipment cords
• Workstation connections
• Frequently moved devices

Nevertheless, stranded conductors usually have higher resistance than equivalent solid conductors. Consequently, patch-cord length forms an important part of the PoE channel design.

Solid conductors

Solid-conductor cable normally suits permanent horizontal cabling. Therefore, it commonly runs between a patch panel and a telecommunications outlet.

Solid cable generally provides lower resistance than an equivalent stranded conductor. However, it is less suitable for repeated movement or tight equipment connections.

PoE Cable Length and Voltage Drop

A conventional structured cabling channel can extend up to 100 metres for supported Ethernet and PoE applications.

Typically, the channel includes:

• Up to 90 metres of permanent cable
• Patch-panel and outlet connections
• Patch and equipment cords
• A total channel length of up to 100 metres

Higher-power PoE does not automatically reduce this standard channel to 55 or 70 metres. However, the channel must still comply with the applicable electrical, transmission and installation requirements.

Longer copper paths create greater resistance. Therefore, shorter channels generally produce less voltage drop and heat.

Additionally, excessively long patch leads can increase resistance because stranded conductors usually have greater attenuation and resistance than permanent solid cable. Consequently, designers should calculate the complete channel rather than considering only the horizontal cable.

Cable Bundles and Temperature

Electrical current produces heat as it travels through copper conductors. Although this effect may be small in an individual cable, temperature can accumulate when many PoE cables are bundled together.

Bundle heating depends on:

• Number of energised cables
• Current per conductor
• Conductor resistance
• Cable diameter
• Jacket material
• Ambient temperature
• Ventilation
• Pathway design

As conductor temperature increases, copper resistance also increases. Therefore, the cable may experience additional voltage drop and insertion loss.

For this reason, higher-power PoE installations require suitable bundle planning. Moreover, cable trays, conduits and cabinet managers should not be overfilled.

What Is DC Resistance Unbalance?

DC resistance unbalance occurs when conductors or pairs within a cable channel have unequal resistance.

PoE equipment expects current to divide appropriately between the conductors used for power. However, poor terminations or inconsistent conductor resistance can cause one conductor to carry more current than another.

Possible causes include:

• Incomplete terminations
• Damaged conductors
• Contaminated contacts
• Incompatible plugs or jacks
• Inconsistent conductor materials
• Poor connector workmanship
• Excessively untwisted pairs

Consequently, an Ethernet channel may pass a simple wiremap test but still perform poorly under a PoE load.

Therefore, higher-power installations may require certification that assesses DC loop resistance and resistance unbalance as well as data-transmission performance.

UTP Versus Shielded Cable for PoE

Both unshielded and shielded copper cables can carry PoE.

UTP relies on balanced twisted pairs to control interference. Therefore, it commonly suits offices, schools, homes and other conventional commercial environments.

Shielded cables add metallic screening around the cable bundle, individual pairs or both. Consequently, they may suit environments with identified electromagnetic-interference risks.

However, shielding does not directly reduce conductor resistance or PoE voltage drop. Furthermore, a shielded cable must form part of a coordinated system that maintains shield continuity through compatible plugs, jacks, patch panels and patch leads.

Earthing and bonding must also follow the system design and applicable requirements. Therefore, installing one shielded patch lead does not convert an unshielded channel into a properly coordinated shielded system.

For a detailed explanation of U/UTP, F/UTP, U/FTP and S/FTP constructions, see our Shielded Ethernet Cable guide.

Connectors and Contact Quality

Every PoE circuit passes through connector contacts. Therefore, contact resistance and termination quality can affect both voltage drop and localised heating.

Common problems include:

• Poorly crimped plugs
• Partially seated conductors
• Damaged jack contacts
• Contamination
• Corrosion
• Repeated connection under electrical load
• Plugs that do not suit the conductor type
• Excessive conductor untwisting

Furthermore, different plugs may suit solid or stranded conductors. They may also accept different conductor gauges and insulation diameters.

Consequently, connectors should be selected for the precise cable construction rather than only the category marking.

Factory-terminated Cat 6 patch leads can reduce the risk of incorrect plug selection and inconsistent field crimping.

PoE Applications

The required cable design depends partly on the connected device.

Wireless access points

Modern access points may require multigigabit Ethernet and higher-power PoE. Therefore, both data performance and power delivery must be considered.

IP surveillance cameras

Many cameras use modest data rates. However, heaters, infrared illumination, pan-tilt-zoom mechanisms and outdoor accessories can increase their power requirements.

VoIP telephones

VoIP handsets commonly use lower-power PoE. Nevertheless, reliable cabling remains important because one connection carries both communications and device power.

Access-control systems

PoE can power controllers, readers, intercoms and related security equipment. Consequently, availability and power budgets may be more important than raw Ethernet speed.

Building automation

Sensors, controllers and lighting systems can create large bundles of continuously energised cables. Therefore, current load, temperature and pathway capacity require careful planning.

Testing a PoE Copper Channel

A basic continuity tester confirms conductor order and simple connection faults. However, it does not prove Category 6 performance or higher-power PoE suitability.

A suitable test program may include:

• Wiremap
• Channel length
• Insertion loss
• Return loss
• Crosstalk
• DC loop resistance
• Resistance unbalance
• PoE classification
• Loaded voltage
• Available power

Insertion loss measures the reduction in signal strength through the channel. Meanwhile, return loss measures signal reflections caused by impedance variations.

For a detailed explanation, read our Ethernet Cable Insertion Loss vs Return Loss guide.

Australian PoE Cabling Requirements

Connecting a factory-made patch lead between accessible equipment differs from installing permanent customer cabling through a building.

In Australia, regulated fixed or concealed telecommunications cabling may need to be installed or directly supervised by an appropriately registered cabler.

This can include cable installed through:

• Walls
• Ceilings
• Floor spaces
• Permanent pathways
• Telecommunications outlets
• Structured cabling systems

Furthermore, fixed cabling must follow applicable separation, segregation and installation requirements. Shielding does not replace those obligations.

Before installing or modifying permanent customer cabling, review the Australian Communications and Media Authority’s Cabling Provider Rules.

Frequently Asked Questions About PoE Ethernet Cable

Does PoE require a special Ethernet cable?

PoE uses compatible balanced copper Ethernet cabling. However, the complete channel must suit the required data rate, power level, length and installation environment.

Is Cat 6 suitable for PoE?

Yes. Suitable Cat 6 cable can support compatible PoE applications. Nevertheless, review conductor material, gauge, resistance, temperature and channel specifications rather than relying only on the category.

Is Cat6A required for PoE++?

No. Cat6A is not universally required for IEEE 802.3bt. However, particular projects may specify Cat6A because of data-rate, lifecycle, pathway or thermal requirements.

Can Cat5e carry PoE?

Yes. A compliant Cat5e channel can carry compatible PoE applications. However, the actual cable construction and installation must support the required power load.

Does shielded cable improve PoE power delivery?

Not automatically. Shielding primarily manages electromagnetic interference. In contrast, conductor resistance, length and connection quality have a more direct effect on voltage drop.

Can PoE operate over 100 metres?

The conventional structured cabling channel limit is 100 metres. Therefore, systems requiring greater distance generally need an intermediate network device, fibre connection or approved Ethernet-extension solution.

Does PoE slow down Ethernet data?

PoE does not inherently reduce the negotiated Ethernet speed. However, cable faults, excessive length, poor terminations or inadequate transmission performance can affect data reliability.

Can a continuity tester certify a PoE cable?

No. Continuity testing confirms basic conductor paths. However, it does not certify category performance, resistance unbalance or power delivery under load.

Can I use CCA cable for PoE?

CCA cable has greater resistance than solid copper cable and may not satisfy the project’s performance or compliance requirements. Therefore, solid copper conductors provide the more dependable selection for structured network cabling.

Are all eight conductors needed?

Gigabit and multigigabit Ethernet use all four pairs. Moreover, four-pair PoE uses all four pairs for power delivery. Consequently, every conductor and contact must be correctly terminated.

Choosing the Right PoE Ethernet Cable

A reliable PoE Ethernet cable must support both the required data application and the electrical load of the powered device.

Therefore, begin by confirming the IEEE PoE type, PSE output and powered-device requirement. Next, review cable category, conductor material, gauge, length and resistance. Additionally, consider bundle temperature, pathway capacity, connector compatibility and installation conditions.

Cat 6 often provides a practical balance for new office, surveillance, wireless and commercial networks. However, category alone does not guarantee PoE performance. Instead, every part of the channel must operate as a coordinated system.

For ready-to-use equipment and patch-panel connections, explore RapidConnect Cat 6 Patch Cables. The range provides 24AWG copper construction, UTP twisted pairs, LSZH jackets, 250 MHz performance and multiple length and colour options.

For product selection, project quantities or availability, contact Anderson Corporation on 03 9761 7600 or sales@andcorp.com.au.