Will 28 AWG Wire Work with Power over Ethernet (PoE) and How?

PoE technology streamlines building infrastructure by delivering power and data over Ethernet cables. But can thin cables like 28 AWG wire handle PoE? This article explores this question and offers guidance on deploying 28 AWG wires for PoE applications.

What Is 28 AWG Wire

When selecting Cat5e, Cat6, or Cat6a network cables, you'll likely see an AWG notation on the cable jacket, such as 28 AWG, 26 AWG, or 24 AWG. AWG stands for American wire gauge, a system for indicating wire diameter. The higher the AWG number, the thinner the wire and the smaller the diameter. For instance, 24 AWG equals 0.0201 inches, 26 AWG equals 0.0159 inches, and 28 AWG equals 0.0126 inches. Compared to 24 AWG cables, 28 AWG wires are over 50% smaller. Additionally, they improve airflow in dense racks and are easier to install in tight spaces. See the image below for a visual comparison of 24 AWG, 26 AWG, and 28 AWG cables.

Can 28 AWG Wire Work with PoE

As devices increasingly rely on PoE connections, such as wireless APs and surveillance cameras, the compatibility of 28 AWG copper wires with PoE applications has become a pressing inquiry. Before addressing this, several key considerations must be acknowledged:

• Thinner cables imply smaller conductors.

• Using smaller conductors for PoE transmission generates more heat, necessitating compensation.

• The compact nature of thin cables in bundles exacerbates heat accumulation, potentially compromising performance and exceeding jacket ratings.

Fortunately, 28 AWG wires have been validated for power delivery. TSB-184-A-1, an addendum to TSB-184-A, confirms their suitability for PoE up to 60W. For applications exceeding 30W, TSB-184-A-1 outlines guidance on bundle separation. The following elucidates the recommendations outlined in TSB-184-A for deploying 28 AWG cables to support power delivery.

How to Deploy 28 AWG Wire for PoE

1. Utilize Bundle in Small Groups: To manage temperature rise effectively, group 28 AWG copper wires in bundles of 12 or fewer. This helps mitigate temperature effects, ensuring adherence to the suggested maximum rise of 15 degrees Celsius and facilitating proper heat dissipation and airflow.

2. Maintain Separation Distance: To support power delivery exceeding 30W and optimize airflow for heat dissipation, maintain a separation distance of at least 1.5 inches between the outer edges of each 28 AWG cable bundle.

3. Avoid Conduit/Enclosures and Overfilling: Since 28 AWG wires are restricted to channel use as patch cords, it's advisable to avoid placing them in conduits or enclosures prone to heat buildup. Additionally, refrain from overfilling cable management components to prevent suppressing heat dissipation and causing cable temperatures to exceed recommended levels.

Note: There are no limitations on installation location or bundle size for 28 AWG copper wires when not distributing power over the network. These restrictions only apply in PoE scenarios. Also, remember that 28 AWG wires should not serve as horizontal or backbone cabling due to their maximum distance limitation of 10 meters according to standards.

Conclusion

In summary, while using 28 AWG wire for Power over Ethernet (PoE) requires careful management, it is possible with proper bundling and adherence to guidelines like TSB-184-A-1. By ensuring adequate separation and ventilation, the challenges of heat accumulation can be addressed, enabling reliable power delivery to PoE devices. Understanding the capabilities and limitations of 28 AWG wire allows for efficient and safe deployment of PoE infrastructure.