Is PoE technology safe to use? Can it damage my equipment?

PoE Lighting Electrical SafetyPoE Lighting Electrical Safety the IEEE 802.3af/at/bt compliant PoE technology is safe. PoE injectors and switches will not damage any equipment, even if the equipment is not designed for PoE applications. Before the PSE sends any power to a connected PD, the PSE initiates a handshake procedure that establishes how much power the connected device requires. This procedure uses low voltage and is harmless to any connected device, PoE or non-PoE. If the handshake is completed, the PoE injector or switch begins sending power, which triggers the PD to start up. If that handshake is not completed for any reason, the PSE never sends any power. It is this built-in feature of all IEEE 802.3af/at/bt-compliant devices that makes PoE technology inherently safe.

Power Over Ethernet (POE) is an increasingly popular way to take a data cable such as a Cat 5 or Cat 6 and use it to power things like LED lighting or other low energy consuming equipment that can operate at limited voltage levels.

As the application of POE becomes more prevalent, so also does the opportunity for misapplication of the cables outside of the scope of their rating or current carrying capacity.

A listed data cable marked with “LP” on the jacket has been subjected to additional testing beyond that of a normal data cable to see how it performs when bundled tightly with other cables that are also carrying power and data. Many regular data cable types are permitted to carry both power and data by the NEC, but a special allowance is given in 725.144(B) for those listed with the LP designation.

In the 2020 NEC, a Section 725.144(B) was revised to clarify the proper application of Class 2 and Class 3 cables with the LP suffix that transmit power and data. The previous 2017 language was a bit confusing when applying ampacity Table 725.144 and led the code reader to think that a LP cable with a marked current level of .5 amps for example, could never be used at a higher ampacity than .5 amps.

An LP cable marked with a current rating of .5 amps for example, means that even if the number of LP cables in a bundle exceeds 192 (the max number of cables mentioned in Table 725.144), the LP cable still has an ampacity of .5 amps.

If six LP cables are bundled without maintaining spacing for example, Table 725.144 is then used to determine the ampacity of the LP cables rather than the marked current rating of the cable. In many cases, the table values might yield a higher allowable ampacity for the cable than its marked current rating.

Below is a preview of the NEC. See the actual NEC text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC edition of NFPA 70.

2020 Code Language:

725.144(B) Use of Class 2-LP or Class 3-LP Cables to Transmit Power and Data. Types CL3P-LP, CL2P-LP, CL3R-LP, CL2R-LP, CL3-LP, or CL2-LP shall be permitted to supply power to equipment from a power source with a rated current per conductor up to the marked current limit located immediately following the suffix “-LP” and shall be permitted to transmit data to the equipment. Where the number of bundled LP cables is 192 or less and the selected ampacity of the cables in accordance with Table 725.144 exceeds the marked current limit of the cable, the ampacity determined from the table shall be permitted to be used. For ambient temperatures above 30°C (86°F), the correction factors of Table 310.15(B)(1) or Equation 310.15(B) shall apply. The Class 2-LP and Class 3-LP cables shall comply with the following, as applicable:

(1) Cables with the suffix “-LP” shall be permitted to be installed in bundles, raceways, cable trays, communications raceways, and cable routing assemblies.

(2) Cables with the suffix “-LP” and a marked current limit shall follow the substitution hierarchy of Table 725.154 and Figure 725.154(A) for the cable type without the suffix “-LP” and without the marked current limit.

(3) System design shall be permitted by qualified persons under engineering supervision.

In summation is PoE Lighting Electrical Safety a concern? The answer is no, Luminetworx™ falls below the 60 watt threshold at 30 watts. Additionally since we encourage our resellers to only install using class 2 or 3 LP category plenum rated cabling which allows for .5 amps per conduit (total of 4) and Luminetworx™ only uses .95 amps total, we are 50 percent below the max cable rating. Luminetworx™ PoE lighting is safe as per National Electrical Code guidelines.

 

If you would like to learn more about the Luminetworx™ PoE lighting and controls contact us now.

 

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