# PoE - Cabling

[PoE](/content/blog-collection/category/PoE/index.html)

Mar 14

Written By [Josh Varghese](/content/blog-collection?author=5e0f8bc570e78867aab8d4f3/index.html)

**Cabling**  
Cabling is important because it directly impacts energy efficiency and heat generation.

When picking cabling for your PoE system, it is important to make sure you consider four parameters:

- Conductor gauge size  
- Cable construction  
- Cable temperature rating  
- Installation type

Example of temperature difference of various ethernet cable constructions  
[_Source_](/content/s/PoE-Cabling-White-Paper.pdf)

**Conductor Gauge Size**  
You may be familiar with Cat 5, Cat 5e, and Cat 6 ethernet cables. These categories are important for PoE heat generation just as they are for data transfer speeds. Cat 6 has a higher conductor gauge than Cat 5e which means a lower resistance, and therefore, less heat generation. Compared to Cat 5e, Cat 6 has about 80% of the heat generation.

[_Source_](/content/s/PoE-Cabling-White-Paper.pdf)

**Cable Construction**  
When it comes to cabling, there are different levels of shielding and foil. Generally, shielding and foil are known to mitigate electromagnetic interference and crosstalk. For PoE, F/UTP (Foiled w/Unshielded Twisted Pairs) has been shown to be 40% more effective at heat dissipation than UTP (Unshielded Twisted Pairs).

[_Source_](/content/s/PoE-Cabling-White-Paper.pdf)

**Cable Temperature Rating**  
Cables have different ratings for ambient temperature that can affect power dissipation as well. Typical cable ambient temperature ratings are 60 °C, 75 °C and 90 °C. There are also special ratings such as 200 °C.

Shielded cables have better performance against temperature affects as shown below.

[_Source_](/content/s/PoE-Cabling-White-Paper.pdf)

**Installation Type**  
Lastly, the way the cables are installed can affect the temperature rise. The larger the bundle of cables, the larger the temperature rise. Below is a chart to show the affect of bundle size.

[_Source_](/content/s/PoE-Cabling-White-Paper.pdf)

For more information, check out the testing that Hitachi performed in their lab.

[Hitachi - Selecting Cables for Power over Ethernet](https://www.hca.hitachi-cable.com/products/hca/paper/POE-White-Paper.pdf)