Cat 6A Vs. Cat 5e for POE networking purposes
Comparative Power over Ethernet Testing Between Cat6A and Cat5e
In a world where we are striving to become "green" by saving energy and being more efficient, Cat 6A offers a "green" solution to reduce energy costs by consolidating power and data over a single cable. Cat 6 a is also a better performing cable than Cat5e because of less dissipation of power when running POE applications. POE works by powering two pairs of a data cable by a switch or hub. the table below shows how POE is done on data communications cable.
(PoE) is able to power a wide verity of products such as telephones, cameras, wireless routers and time clocks. IEEE 802.3af is the current standard for this technology. the stages of powering up and defining the different class rating and maximum power levels are included in the 802.3af. This standard is for devices that use 25 to 30 watts of power. with expanding power specifications new hardware will be created. what we could see is advanced audio conferencing equipment, pan-tilt-zoom (PTZ) network cameras, powered computer devices, and larder wireless coverage.
To show the advanced energy efficiency Cat6A has over Cat5e for Poe, DC resistance testing was completed with both cable types, end-span Power-Sourcing Equipment (PSE), and two different Classes of Powered Devices (PDs). A Fluke Net Tools Series II was used to monitor the current, voltage, and power demands of the PDs. For the tests, pins 1,2,3,6 were powered across 316' of both Cat5e and Cat6A.
#1- The power requirements were collected by using the Fluke meter to the PSE. The class two device an Avaya phone was drawing 4.93 watts. The class threee device An Cisco Aironet 1200 was drawing 7.5 watts.
#2- Testing the the two cables inline with the PDs. the power was monitored and recorded at the inputs of each device.
The pins 3&6 are the pins that deliver the power from the source to the powered device. Pins 1&2 are the pins that return to the source from the powered device. Since the pins run parallel they were able to test the resistance in parallel.
A Cat5e cable powering an Avaya phone that draws .096 amps had dissipated approximately 82 MW.
A Cat 6A cable powering an Avaya phone that draws .096 amps had dissipated approximately 56 MW.
A Cat 5e cable powering a Cisco AirNet 1200 that draws .150 amps had dissipated approximately 201 MW.
A Cat 6A cable powering a Cisco AirNet 1200 that draws .150 amps had dissipated approximately 137 MW.
Resistance over a 150’ cableCat5e_Resistance= 4.48 ohmsCat6A_Resistance= 3.05 ohms
With all of that said an office with 100 power over Ethernet devices could save about $90 a year by using Cat6A rather than Cat5e.Cat 6A is a by fare a better cable when it comes to (POE) and network stability. With an ever changing world working towards saving resources, becoming "Green" we will see more (POE) applications making Cat 6A cable even more effective in the future.
There are many applications and environments that need to have the future growth potential put in place before hand. It is much easier to replace equipment compared to continuously changing your structured cabling. In most cases it is good to take a moment to think of what you want out of your network, how long you plan on staying as well as what kind of equipment you intend to push before making a decision on the type of cable for your network. If your are running a basic network and see your company adapting to the new technologies being produced there is a need for the extreme cable such as Cat 6A. One of the benefits is backward capabilities meaning that you can run Cat 5 equipment across a Cat6 network
References; General Cable, (PDF) Titled; (Comparative Power-Over-Ethernet (POE) Testing Between Category 6A and Category 5e Cables), written by Rob Gould, Engineer, Data com Products.
Fluke Nettools Series II Tester
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