PoE Standards X Network Cabling Categories

Power over Ethernet (PoE) is the technology that enables data transmission along with electrical power
over a four-pair twisted pair network cable (LAN), by providing power and data simultaneously to remote
devices. This application has significantly altered cabling infrastructure networks, as it provides
considerable reduction in installation costs.
With the increasing popularity of Ethernet, new types of devices are being over-connected to the
structured cabling network: high-definition security cameras, IP phones, RFID (Radio Frequency
Identification) readers, wireless access points, sensors, access controls, LED lighting and more.
These devices have an increasingly high power requirement, which has required continued development
of PoE standards by IEEE 802.3 working groups.
When it began, in 2003, there was only the IEEE 802.3af standard, which used 2 pairs for a power of
15.4W output with 350 mA current per pair. Further on, it was developed PoE+, which delivers 30W in 2
pairs with a current of 600mA per pair. Today, PoE is already in its 802.3bt 4PPoE standard, which
provides a maximum output power of 99.9W using the 4 pairs with a 1000mA current by pair.
It is important to remember that all the levels of PoE existing to date comply with the SELV (Safety Extra
Low Voltage) classification, ie, 60 Volts / 100 Watts per IEC 60950-1. This makes PoE a very secure
technology for power and data delivery via twisted-pair cables for LAN.