PoE at 200, 300 or Even 1700 Meters? What AEM Networks Measurements Reveal
Why Verifying Data Speed Alone Is No Longer Enough in Modern PoE Networks
In today’s networking environments, requirements increasingly extend beyond the traditional 100-meter Ethernet distance limit. Campuses, industrial facilities, logistics centers, video surveillance systems, smart buildings, and IoT infrastructures all require reliable connectivity over significantly longer distances, often without the need for additional telecommunications rooms or fiber-optic links.
This raises an important question: can a network still deliver sufficient bandwidth and enough power for connected devices via Power over Ethernet (PoE) when operating beyond standard Ethernet distances?
The latest technical white paper from AEM Networks provides compelling answers based on real-world measurements performed using the AEM TestPro CV100 Cable Certification Platform.
The Problem Is Not Always the Signal. Often, It’s the Power.
Traditional cable certification focuses primarily on parameters such as:
- Insertion Loss (IL)
- Return Loss (RL)
- Near-End Crosstalk (NEXT)
- Equal Level Far-End Crosstalk (ELFEXT)
- Delay and Delay Skew
These measurements determine transmission quality and directly impact the Signal-to-Noise Ratio (SNR) of the link.
However, in modern PoE deployments, another critical parameter comes into play: DC Loop Resistance.
Every meter of copper cable adds electrical resistance. As resistance increases, part of the transmitted power is dissipated as heat before it reaches the Powered Device (PD).
As a result, a link may successfully pass certification while the connected device still experiences operational issues due to insufficient voltage at the far end.
This is precisely why AEM recommends supplementing Extended Reach cable certification with actual PoE load testing.
A Surprising Result: 200 Meters with Nearly the Same PoE Power
One of the most remarkable findings in the study is the comparison between:
- Standard Cat5e 24 AWG cabling at 100 meters
- CatxL 22 AWG Extended Reach cabling at 200 meters
At first glance, one would expect a significant performance penalty.
The measurements tell a different story.
The standard 100-meter Cat5e channel delivered 79.1 W of PoE power.
The 200-meter CatxL channel delivered 77.7 W.
The difference is less than 2%.
| Cable Configuration | Length | PoE Power Delivered |
| Cat5e 24AWG | 100 m | 79.1 W |
| CatxL 22AWG | 200 m | 77.7 W |
| CatxL 22AWG | 250 m | 72.1 W |
| CatxL 22AWG | 300 m | 66.5 W |
PoE Power Delivery vs. Distance: AEM TestPro CV100 Field Measurements. Source: AEM Networks White Paper, 2026.
The explanation lies in conductor size. A 22 AWG conductor has substantially lower resistance per meter than a standard 24 AWG conductor, effectively compensating for the additional cable length.
For network designers, consultants, and installers, this means that selecting the appropriate cable can effectively double the channel length without significantly impacting PoE performance or data throughput.
Where Do the Trade-Offs Begin?
At approximately 250 meters, the effects of distance become more apparent.
| Distance | Typical data Rate |
| Up to 200 m | 1 Gbps |
| Up to 250 m | 100 Mbps |
| Up to 300–350 m | 10 Mbps |
| Up to 1700 m (SPE) | 10BASE-T1L |
Typical Data Rates at Extended Distances. Based on AEM Networks field measurements.
Gigabit Ethernet is no longer sustainable, and the link transitions to 100 Mbps operation.
Despite this reduction in data rate, the channel still delivers more than 72 W of PoE power, which remains more than adequate for many applications, including:
- IP surveillance cameras
- Wi-Fi access points
- Access control systems
- IoT gateways
At 300 meters, the channel can still support 10 Mbps Ethernet while delivering approximately 66 W of PoE power.
However, this is where an important limitation emerges.
The voltage at the Powered Device falls below the minimum voltage specified by the IEEE 802.3bt standard. Before deployment, installers should therefore verify that the target device can operate reliably at lower input voltages.
Single Pair Ethernet Opens an Entirely New Possibility
A particularly interesting part of the study focuses on Single Pair Ethernet (SPE).
AEM performed measurements on a 1700-meter SPE channel using 23 AWG Single Pair Ethernet cabling.
This is approximately 70% beyond the 1000-meter distance specified by IEEE 802.3cg for 10BASE-T1L.
While power delivery is no longer practical at this distance, data communication remains functional.
For industrial environments, energy infrastructure, smart city deployments, and remote sensor networks, this presents an attractive alternative to fiber-optic installations, allowing data transmission over a single copper pair.
Why SNR Margin Matters
In cable certification, the result is not simply about PASS or FAIL.
Equally important is the amount of margin remaining before a parameter reaches its limit.
For this reason, AEM emphasizes monitoring SNR Margin.
A positive margin indicates that the link retains sufficient operational headroom to tolerate:
- Temperature fluctuations
- Component aging
- Additional connections and terminations
- Mechanical stress
- Environmental variations
For Extended Reach installations, AEM recommends maintaining a minimum 3 dB margin wherever possible.
What Does This Mean for Installers and Certifiers?
The white paper clearly demonstrates that in modern PoE deployments, the traditional mindset of “PASS = Project Complete” is no longer sufficient.
Reliable network operation requires verification of:
- RF transmission parameters
- DC Loop Resistance
- Actual PoE load performance
- Voltage available at the Powered Device
- SNR margins
This is precisely why advanced certification platforms such as the AEM TestPro CV100 are becoming essential tools for modern network validation.
This is particularly true for projects involving smart buildings, industrial Ethernet, campus networks, video surveillance systems, and emerging Single Pair Ethernet deployments.
Conclusion
The measurements conducted by AEM Networks demonstrate that the traditional 100-meter Ethernet limit is no longer an absolute constraint.
With proper cable selection, careful network design, and advanced certification methodologies, significantly longer distances can be achieved without compromising data transmission reliability or PoE power delivery.
Perhaps the most important lesson from the study is this:
In Extended Reach deployments, the critical question is often not whether the link passes certification, but how much power actually reaches the Powered Device.
Link certification is only the first step. In modern PoE networks, it is equally important to verify the actual voltage, current, and power delivered to the Powered Device at the far end of the link.
AEM TestPro CV100 enables IEEE 802.3bt PoE load simulation while measuring the actual voltage, current, and power delivered over the connection. This allows installers and network professionals to verify not only that a link passes certification, but also that the connected device will operate reliably under real-world conditions at the remote end of the cable run.
Want to Learn More?
This article is based on the technical white paper:
Arvind C. Patel, Director of Engineering, AEM Networks
Power over Ethernet & Signal-to-Noise Ratio Performance on Extended Reach Copper Cabling from 100m to 1700m: Measurements, Analysis, and Deployment Guidance
AEM Networks White Paper, June 2026.
The study is based on real-world measurements performed using the AEM TestPro CV100 Cable Certification Platform across multiple copper and Single Pair Ethernet channel configurations ranging from 100 m to 1700 m.
The EGAL team can help you evaluate AEM Networks solutions for copper, fiber optic, and Single Pair Ethernet certification and demonstrate how TestPro CV100 can verify both transmission performance and actual PoE delivery capability.
For more information about AEM Networks certification, testing, and network diagnostic solutions, contact us at sales@egal-eu.com or give us a call +386 (0)31 737 831.
