Power over Ethernet (PoE) for Access Control
In access control systems, the hassle of running separate cables for power and data has long been a pain point—especially for retrofits or large facilities like campuses and office parks. Power over Ethernet (PoE) changes the game by delivering both power and data over a single twisted-pair cable, simplifying installation, cutting costs, and boosting reliability. For access control devices like card readers, electronic locks, and controllers, PoE isn’t just a “nice-to-have”—it’s a transformative solution that aligns with modern smart security needs. This guide breaks down how PoE works for access control, its key benefits, selection tips, and real-world applications.
What Is PoE, and How Does It Work for Access Control? Core Definition
PoE is an IEEE-standardised technology that transmits electrical power (DC) and Ethernet data simultaneously over a single Cat5e/Cat6 cable. For access control, this means devices like PoE-enabled card readers, biometric scanners, and door controllers no longer need separate power cords or nearby electrical outlets—one cable handles everything.
Key Transmission Modes for Access Control
Two standardised PoE transmission methods adapt to different access control scenarios:
1. Alternative A (Data Pair Power)
Uses 2 of the 4 twisted pairs in Cat5e/Cat6 cables (the same pairs for data). Ideal for low-power access control devices (e.g., basic card readers, keypads) in small offices. Note: Troubleshooting can be tricky since power and data share pairs.
2. Alternative B (Spare Pair Power)
Uses 4 pairs in Cat6/Cat6a cables, separating power and data into distinct pairs. Perfect for high-power access control setups (e.g., video intercoms, motorised electronic locks) or large facilities—easier to diagnose wiring issues and more reliable for long runs.
Critical PoE Standards for Access Control
PoE has evolved to match growing access control power demands—choose the right standard based on your devices:
| Standard | Nickname | Max Power (Source) | Suitable Access Control Devices | Cable Requirement |
| IEEE 802.3af | PoE Basic | 15.4W | Video intercoms, biometric scanners, and electric strikes | Cat5e+ |
| IEEE 802.3at | PoE+ | 30W | Motorised magnetic locks, multi-functional access panels | Cat5e+ |
| IEEE 802.3bt | PoE++ Type 3 | 60W | Motorized magnetic locks, multi-functional access panels | Cat6+ |
| IEEE 802.3bt | PoE++ Type 4 | 90W | Integrated access-control-video systems, outdoor smart gates | Cat6a+ |
All standards support 100m maximum cable length—critical for large facilities like campuses.
6 Unbeatable Benefits of PoE for Access Control
PoE’s dominance in modern access control stems from its ability to solve real-world operational pain points:
1. Slash Installation & Labour Costs
No need for electricians to run dedicated power lines—IT teams can install PoE cables. For a 50-door office, this cuts wiring labor by 60% and eliminates costs for extra power outlets or junction boxes.
2. Flexible Device Placement
Install readers or intercoms in optimal security spots (e.g., ceiling-mounted scanners, remote gate entrances) without relying on nearby outlets. Rearrange devices easily during office renovations.
3. Enhanced Security & Safety
PoE systems include built-in protection against overload, short circuits, and incorrect wiring—preventing damage to expensive access control gear. Low-voltage power (48V DC) also reduces fire risks vs. high-voltage AC.
4. Uninterrupted Reliability
Centralised PoE switches connect to UPS (Uninterruptible Power Supply) systems. During power outages, critical access points (e.g., emergency exits, server room doors) stay operational—avoiding security gaps.
5. Centralised Management
Monitor the power usage of access control devices via PoE switches. Remotely reset unresponsive readers or lock/unlock doors without on-site visits—ideal for multi-location businesses.
6. Future-Proof Scalability
Add new devices (e.g., upgrade from card readers to biometric scanners) by simply connecting to existing PoE switches—no need to rewire for more power.
How to Choose the Right PoE Solution for Access Control
Avoid costly mismatches with these 4 key steps:
1. Calculate Device Power Needs
List all access control devices and their power draws: Basic readers (5-10W → 802.3af), video intercoms (15-25W → 802.3at), motorised locks (30-50W → 802.3bt Type 3).
2. Select the Right Cable
Use Cat5e for 802.3af/at; upgrade to Cat6 for 802.3bt (reduces signal loss for high power). For outdoor access points (e.g., parking lot gates), choose weatherproof shielded Cat6a.
3. Pick a Reliable PoE Switch
Opt for “managed” PoE switches (vs. unmanaged) to monitor device status and power usage. Ensure the switch has enough ports for current devices + 20% spare for future expansion.
4. Verify Compatibility
Confirm access control devices (readers, controllers) are PoE-certified (look for IEEE 802.3af/at/bt logos). Avoid mixing proprietary PoE gear (e.g., old Cisco UPOE) with standard devices.