What standards apply to POE++?

PoE++ follows the IEEE 802.3bt standard, the latest advancement in Power over Ethernet (PoE) technology, designed to support devices that require higher power levels than previous PoE standards. IEEE 802.3bt, which was ratified in 2018, defines two key power delivery types—Type 3 and Type 4—each with specific power capacities and features. Here is a detailed look at the standards, their specifications, and how they apply to PoE++:

IEEE 802.3bt Standard Overview

--- The IEEE 802.3bt standard, often referred to as PoE++ or 4-Pair PoE, enables higher power transmission over Ethernet cables to meet the requirements of more demanding devices. Unlike previous standards (IEEE 802.3af and IEEE 802.3at), which deliver power through two of the four pairs in an Ethernet cable, 802.3bt utilizes all four pairs, thereby increasing the power that can be safely delivered without risking network interference or signal degradation.

Key Components of IEEE 802.3bt (PoE++)

The IEEE 802.3bt standard is divided into two main types:

--- Type 3 (60W, also known as PoE++)

--- Type 4 (100W, also known as Ultra PoE)

Each type specifies the maximum power delivery per port, voltage ranges, and current levels that can be transmitted over a single Ethernet cable.

1. Type 3 (PoE++ 60W)

Type 3 of the IEEE 802.3bt standard is an intermediate power level, providing up to 60 watts per port at the Power Sourcing Equipment (PSE) and 51 watts at the Powered Device (PD), factoring in power loss over the cable. Type 3 is ideal for devices with moderate to high power demands, such as:

--- PTZ cameras (Pan-Tilt-Zoom)

--- High-performance Wi-Fi 6 access points

--- Multi-radio wireless access points

--- LED lighting systems

Type 3 specifications:

--- Power at Source (PSE): 60W

--- Power at Device (PD): 51W

--- Voltage Range: 50-57V DC

--- Current: Up to 600mA per pair

--- Pairs Used: 4 pairs (all pairs in the Ethernet cable)

Type 3 improves power delivery over two pairs used in previous standards (802.3af and 802.3at) by doubling the current-carrying capacity, allowing safe and efficient power transmission across greater distances.

2. Type 4 (PoE++ 100W or Ultra PoE)

Type 4 is the highest level within the 802.3bt standard, allowing up to 100 watts at the PSE and up to 71 watts at the PD after considering power loss. Type 4 is intended for high-powered devices that require substantial energy, including:

--- High-end PTZ cameras with full night vision and heating

--- Digital signage and interactive displays

--- Advanced building automation devices

--- Industrial equipment (e.g., sensors and actuators)

--- USB-C charging stations (for devices like laptops or tablets)

Type 4 specifications:

--- Power at Source (PSE): 100W

--- Power at Device (PD): 71W

--- Voltage Range: 52-57V DC

--- Current: Up to 960mA per pair

--- Pairs Used: 4 pairs

By using all four twisted pairs in the Ethernet cable, Type 4 PoE++ distributes the current more evenly, reducing heat buildup and allowing for higher wattage delivery over longer distances.

IEEE 802.3bt Features and Enhancements

Beyond just higher power, IEEE 802.3bt includes several new features designed to improve efficiency, compatibility, and overall network performance:

1.Four-Pair Power Delivery: By using all four pairs in an Ethernet cable, IEEE 802.3bt can deliver higher power without increasing the current on any individual pair excessively, which helps maintain safety and reduces heat.

2. Backward Compatibility: PoE++ is backward-compatible with older standards like IEEE 802.3af (PoE) and IEEE 802.3at (PoE+). This means PoE++ switches can detect and adjust power output to safely support legacy PoE and PoE+ devices.

3.Enhanced Power Management:

--- Autoclass: This feature enables the PSE to determine the exact power requirements of the PD during initial connection. The PSE then dynamically allocates only the necessary amount of power, optimizing energy efficiency across the network.

--- LLDP (Link Layer Discovery Protocol): PoE++ uses LLDP to allow two-way communication between the PSE and PD. This ensures that both devices can negotiate power levels in real-time, adjusting as necessary based on usage or new connections.

4.Safety and Efficiency:

--- Higher Efficiency at Extended Distances: IEEE 802.3bt supports higher voltage, which reduces current draw and minimizes resistive losses over longer cable runs, maintaining energy efficiency.

--- Thermal Management: By distributing power across all four pairs, IEEE 802.3bt reduces heat generation in each pair, making it safer and more efficient, especially for installations where multiple high-power devices are connected.

Cabling Requirements for IEEE 802.3bt

To safely handle the power levels in IEEE 802.3bt, it is recommended to use Category 6 (Cat6) or higher-grade Ethernet cabling:

Cat6 or Cat6a: Both can support PoE++ over the full 100-meter range while minimizing power loss and reducing heat buildup.

Cable Quality Consideration: Thicker cables with lower resistance (such as Cat6a with shielded twisted pairs) are ideal for PoE++ applications, particularly for Type 4, as they allow better power transmission over longer distances.

Common Applications of IEEE 802.3bt (PoE++)

PoE++ enables a range of high-powered applications, including:

Advanced Surveillance Systems: PTZ cameras with full night vision, zoom, and AI processing capabilities.

Wireless Access Points: High-performance Wi-Fi 6 or Wi-Fi 6E access points that require more power to support multi-user data transmission.

Digital Signage and Kiosks: Interactive displays and signage solutions in public spaces.

Industrial IoT Devices: Sensors, actuators, and devices in smart manufacturing or automation systems.

Smart Building Technologies: LED lighting, climate control, and security systems that benefit from centralized control over Ethernet.

Summary

The IEEE 802.3bt standard, defining PoE++ power delivery, is designed to meet the needs of modern, high-powered devices by delivering up to 60W (Type 3) or 100W (Type 4) per port. With features like four-pair power transmission, Autoclass power management, and backward compatibility, IEEE 802.3bt PoE++ has become essential for applications in high-demand environments, such as security, wireless networks, and building automation. Using the right cabling, such as Cat6 or Cat6a, helps ensure safe and efficient operation, making PoE++ a robust solution for powering the next generation of Ethernet-connected devices.