The impact of Power over Ethernet (POE) on data cabling and grounding
Power over Ethernet (POE) is a technology whereby powered devices receive power and signal through a single Ethernet cable. The International Electrical and Electronics Engineers 802 Task Force is responsible for setting the standards that govern Power over Ethernet applications. The industry has standardized the use of Power over Ethernet to ensure that all devices work properly together. Grounding, or bonding a piece of electrical equipment to ground, is considered essential to the proper installation of any type of electrical system, but it becomes even more important when Power over Ethernet enters the equation.
POE standards
There are currently two main standards in use for Power over Ethernet devices. The first standard, IEEE 802.3af-2003, provides devices with up to 15.4 watts of DC power to operate. This translates to approximately 44 volts delivered at 350 milliamps. The upcoming POE standard, IEEE 802.3at-2009, allows up to 25.5 watts of power, with some manufacturers claiming that their devices can deliver up to 51 watts of usable power. Category 5e data cabling is typically specified for POE applications, and when the installation requires the cable to be run outside, the cable must be rated for outdoor use.
Grounding
Grounding, or grounding, is defined as the intentional connection or bonding of electrical equipment to ground. This is to protect equipment and personnel in the event of transient or induced voltages in electrical equipment or wiring. The proper method of grounding an electrical system depends on the size of the system. However, with Power over Ethernet, grounding also protects equipment from lightning strikes when surge protectors are used properly. The POE equipment must be grounded to the same ground used by the building’s power supply equipment and electrical system. The ground connection should be as short and straight as possible, and should be made with a minimum ten gauge bare or insulated copper wire. A quick perusal of a number of point-of-entry-related technical support forums shows that improper grounding is a major cause of point-of-entry systems not working properly and outdoor equipment being damaged beyond repair. during storm activity.
Uses of Power over Ethernet
POE allows you to use powered devices in remote locations. Power over Ethernet allows you to install parking lot surveillance cameras with pan, tilt and zoom capabilities and not have to run a separate set of power lines. Wireless modems, access points and routers can be placed wherever they are needed, whether or not power is easily accessible. Many of the newer VoIP phones work with POE. Increasingly, clocks that are synchronized with the central time system use this technology to power themselves and receive their time signal from the National Observatory’s chronometer.
Terminology
As with any new technology, this one comes with its own terminology. The power supply kit supplies power to the Ethernet cable. The powered device receives power from the PSE through the Ethernet cable. These can be routers, cameras, modems, switches, wireless access points, or a host of other types of devices.