In today’s evolving industrial landscape, devices within Operational Technology (OT) networks demand both consistent data transmission and reliable power delivery. Yet, powering endpoints in remote or space-constrained environments remains a critical challenge. Batteries, while often used, introduce maintenance issues and can compromise long-term reliability.
This is where Single Pair Power over Ethernet (SPoE) steps in. Much like traditional Power over Ethernet (PoE) revolutionized enterprise IT networks, SPoE now offers that same transformation for OT environments—providing both power and data over a single twisted pair of wires.
SPoE is a modern Ethernet standard that delivers power and data through one pair of copper conductors. Unlike traditional PoE, which uses multiple pairs, SPoE simplifies cabling and reduces infrastructure costs. It’s based on the IEEE 802.3cg standard and operates with the 10BASE-T1L 10Mb/s Ethernet protocol—ideal for long-distance, low-power industrial networks.
Although related, SPoE and PoDL serve different markets. SPoE is tailored for OT systems such as industrial automation and building control, focusing on power classification and resilience. PoDL is more commonly found in engineered environments like automotive networks.
SPoE allows for simultaneous transmission of data and power over a single pair, offering:
SPoE systems support plug-and-play configurations. Devices classify themselves before receiving power, ensuring compatibility and safety. Whether you're upgrading or expanding your OT network, SPoE ensures installations are fast and seamless.
SPoE supports multiple classes and voltages to meet diverse power needs:
This flexibility allows network planners to optimize delivery across long distances while avoiding power losses, especially on lower-voltage lines.
SPoE includes smart fault response mechanisms:
Many OT applications are now subject to stringent government and industry power regulations. SPoE supports multiple standby modes, ensuring devices remain compliant without sacrificing performance or responsiveness.
SPoE (Single Pair Ethernet over Power) is a vital technology designed to enhance power delivery in operational technology (OT) networks. In traditional OT deployments, a 24V DC supply voltage is commonly used. However, when power is delivered over long cable runs, significant losses occur due to cable resistance, reducing efficiency. To address this challenge, SPoE offers two distinct operating voltages: 24V DC and 55V DC. The efficiency of power delivery is maximized when the voltage is raised closer to the SELV maximum of 60V DC. This shift significantly reduces power losses, ensuring more reliable and efficient operations over longer distances.
SPoE defines six unique classes tailored to optimize power delivery based on cable length. Classes 10, 11, and 12 are designed for 24V DC delivery over long, medium, and short cables, respectively. Similarly, Classes 13, 14, and 15 enable 55V DC power delivery over long, medium, and short cables. For example, at 55V and a distance of 1000 meters, up to 7.7W can be delivered to the endpoint, while at a shorter distance of 150 meters, 52W can be delivered. This adaptability ensures that OT networks can achieve high power efficiency regardless of the distance between devices, making SPoE an essential technology for modern industrial environments.
| Class | VPSE (V, min/typ/max) | ICABLE (mA, max) | PPD (W, max) | RCABLE (Ohms, max) |
|---|---|---|---|---|
|
10 |
20 / 24 / 30 |
92 |
1.23 |
65 |
|
11 |
20 / 24 / 30 |
240 |
3.2 |
25 |
|
12 |
20 / 24 / 30 |
632 |
8.4 |
9.5 |
|
13 |
50 / 55 / 58 |
231 |
7.7 |
65 |
|
14 |
50 / 55 / 58 |
600 |
20 |
25 |
|
15 |
50 / 55 / 58 |
1579 |
52 |
9.5 |
Before any power is applied, SPoE devices initiate a classification exchange between the Power Sourcing Equipment (PSE) and the Powered Device (PD). This ensures:
Voltage matters in OT environments. Here’s how SPoE optimizes delivery:
Six classes are used to govern this power delivery:
This level of precision empowers engineers to plan resilient, cost-effective power architectures.
Factories, warehouses, and production plants benefit from:
SPoE empowers intelligent infrastructure:
In the expanding world of IoT, SPoE supports:
| Feature | SPoE | Traditional PoE |
|---|---|---|
|
Wire Pairs |
1 pair |
2 or 4 pairs |
|
Max Cable Distance |
Up to 1000m |
Typically 100m |
|
Voltage Options |
24V, 55V |
48V standard |
|
Power Range |
1.23W to 52W |
15.4W to 90W |
|
Target Use Cases |
OT, Industrial, Long Range, IoT |
Office networks, LANs, WiFi APs |
|
Network Safety Features |
Classification, fast power cutoffs |
Power negotiation protocols |
SPoE is not just a short-term solution—it’s shaping the future of Ethernet for OT environments. Industry adoption is increasing rapidly, driven by:
With growing demand across sectors—from manufacturing to smart cities—SPoE is expected to evolve, with future standards potentially delivering higher power and integrating with protocols like Time-Sensitive Networking (TSN).
SPoE introduces not just physical efficiency but also new considerations for network security in Operational Technology environments.
As SPoE delivers both power and data through the same line, cybersecurity strategies must ensure that the data layer remains isolated from any potential power-based exploits. Employing encrypted data streams and VLAN segmentation is essential.
The classification exchange between PSEs and PDs can be monitored for authenticity, ensuring only authorized devices receive power—critical for preventing unauthorized endpoint access.
Even in environments with existing cabling and infrastructure, SPoE can bring enhanced capabilities without massive overhauls.
SPoE media converters allow for the integration of traditional Ethernet and power sources into SPoE topologies, bridging the gap between old and new systems.
Many legacy devices can be upgraded with SPoE-compatible interfaces or connected through adapters that provide compliant power and data delivery over the existing single-pair infrastructure.
One of the most compelling reasons to deploy SPoE is its direct impact on cost-efficiency and return on investment in industrial and smart building applications.
Reducing cabling complexity not only minimizes the initial material investment but also cuts down on labor costs, especially in retrofit scenarios or hard-to-reach locations.
SPoE’s lower power losses, reduced maintenance, and extended cable distances contribute to long-term savings and more reliable network uptime, improving overall ROI.
SPoE is designed for OT systems and supports classification before power is applied. PoDL is typically used in engineered systems like in-vehicle networks and does not use classification.
Depending on the cable length and voltage class, SPoE can deliver from 1.23W up to 52W. For instance, a 55V Class 15 system can deliver 52W at 150m, or 7.7W at 1000m.
Yes. SPoE adheres to industry safety standards including LPS, SELV, and NEC Class 2. It includes smart voltage management to cut power in the event of faults or disconnections.
Absolutely. SPoE is backward-compatible with many existing devices and can be integrated via compliant switches or media converters. It simplifies upgrades without full infrastructure overhauls.
SPoE operates at 24V or 55V, depending on the application. 24V supports legacy systems, while 55V maximizes delivery efficiency over long cable distances.
Single Pair Power over Ethernet (SPoE) is revolutionizing how we connect and power industrial networks. By merging data and power over a single twisted pair, SPoE reduces complexity, cost, and maintenance—making it an ideal solution for scalable, future-ready OT infrastructures.
At Omnitron Systems, we provide cutting-edge SPoE solutions that align with evolving industrial demands. Looking to upgrade or future-proof your network? Contact our team to learn how SPoE can unlock efficiency and performance for your operations.
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