What are the common issues with PoE splitters and how to fix them?

A PoE splitter is a device that separates power and data from a PoE-enabled Ethernet cable, providing both an Ethernet connection and a DC power output for devices that do not natively support PoE. While PoE splitters are useful, they can encounter various issues related to power, data transmission, or compatibility. Below is a detailed guide on common PoE splitter problems and how to fix them.

1. No Power Output from PoE Splitter

Possible Causes:

--- The PoE source is inactive or not providing power.

--- The PoE splitter is faulty or incompatible with the PoE standard.

--- The Ethernet cable is damaged or not properly connected.

--- The PoE switch or injector has power-saving features enabled, preventing power delivery.

How to Fix:

Step 1: Check the PoE Power Source

--- Test the PoE switch or injector by connecting another PoE-powered device (like a PoE camera or access point).

--- Use a PoE tester to check if power is being supplied.

Step 2: Verify PoE Compatibility

Ensure the PoE splitter matches the PoE standard of the power source:

--- 802.3af (PoE): Up to 15.4W

--- 802.3at (PoE+): Up to 30W

--- 802.3bt (PoE++): Up to 60W or 90W

If the PoE source is Passive PoE, ensure the splitter supports passive PoE.

Step 3: Check and Replace the Ethernet Cable

--- Use a Cat5e or higher-rated cable to ensure power delivery.

--- Try a different Ethernet cable to rule out cable failure.

Step 4: Restart PoE Switch or Injector

Some PoE switches disable power on unused ports. Try restarting the switch or manually enabling PoE on the port.

2. PoE Splitter Provides Incorrect Voltage

Possible Causes:

--- The splitter is set to the wrong voltage output (some splitters allow switching between 5V, 9V, 12V, or 24V).

--- The PoE splitter is incompatible with the device’s power requirements.

--- The PoE switch or injector is not supplying enough power to the splitter.

How to Fix:

Step 1: Verify the Splitter’s Voltage Output

--- Check the voltage rating on the splitter and ensure it matches the device’s power requirements.

--- If the splitter has a voltage selection switch, set it to the correct value.

Step 2: Use a Multimeter to Test Voltage

Use a multimeter to measure the DC output of the splitter:

--- Place the red probe on the inner pin (+) and the black probe on the outer ring (-).

--- Ensure the reading matches the expected voltage (e.g., 12V for a 12V device).

Step 3: Upgrade the PoE Power Source

If the splitter is not receiving enough power, upgrade to a PoE+ (802.3at) or PoE++ (802.3bt) injector/switch to ensure sufficient wattage.

3. Device Keeps Restarting or Powering Off Intermittently

Possible Causes:

--- The PoE splitter is not supplying enough power for the connected device.

--- The device has a fluctuating power demand, causing instability.

--- The PoE switch has an overload protection feature, shutting down the port.

How to Fix:

Step 1: Check the Device’s Power Requirements

--- Compare the device’s wattage requirement with the splitter’s power rating.

--- If the device needs 18W, but the splitter only provides 15W, the device may reboot frequently.

Step 2: Upgrade to a Higher-Power PoE Splitter

Use a PoE+ (802.3at) or PoE++ (802.3bt) splitter if the device requires more than 15W.

Step 3: Check for Overload Protection on PoE Switch

--- Some PoE switches disable ports if they detect excess power draw.

--- Try another PoE port or switch to a higher-wattage PoE switch.

4. Network Connection Issues (No Internet, Slow Speeds, or Disconnects)

Possible Causes:

--- The Ethernet cable is faulty or too long, causing signal degradation.

--- The PoE splitter only supports 10/100Mbps, while the network requires Gigabit speeds (1000Mbps).

--- There is interference or a faulty Ethernet connection.

How to Fix:

Step 1: Check the Ethernet Cable

--- Use a Cat6 or Cat6a cable for better speed and signal integrity.

--- Replace the Ethernet cable and test again.

Step 2: Verify Splitter Speed Compatibility

--- If the network requires Gigabit speeds, ensure the PoE splitter supports Gigabit Ethernet (1000Mbps).--- 

--- If using a 10/100Mbps splitter, replace it with a Gigabit PoE splitter.

Step 3: Test with Another Device

--- Try connecting a laptop directly to the PoE splitter’s Ethernet output to see if the network works.

5. PoE Splitter Overheats or Stops Working Over Time

Possible Causes:

The splitter is handling more power than it is rated for.

--- Poor heat dissipation or low-quality components in the splitter.

--- Continuous overload or improper ventilation.

How to Fix:

Step 1: Check the Splitter’s Wattage Capacity

--- If your splitter is rated for 15W but your device requires 18W, overheating may occur.

--- Upgrade to a PoE+ (30W) or PoE++ (60W) splitter.

Step 2: Improve Ventilation

--- Ensure the splitter is placed in a well-ventilated area and not covered by objects.

Step 3: Use a High-Quality PoE Splitter

--- Avoid cheap or unbranded splitters with poor thermal design.

--- Choose a reputable brand that offers overcurrent and thermal protection.

6. PoE Switch or Injector Port Disables Itself

Possible Causes:

--- The PoE switch has overload protection triggered by excess power draw.

--- The PoE splitter is short-circuited or malfunctioning.

--- The switch has power allocation settings, limiting available power.

How to Fix:

Step 1: Reduce Power Load

--- If multiple PoE devices are connected, try unplugging some devices to reduce total power consumption.

Step 2: Reset the PoE Port

--- Disable and re-enable PoE on the port via the switch settings.

--- Try plugging the splitter into a different PoE port.

Step 3: Replace the PoE Splitter

--- If the issue persists, try a different PoE splitter to rule out a faulty unit.

Conclusion

Summary of Common PoE Splitter Issues & Fixes

By following these troubleshooting steps, you can identify and resolve PoE splitter problems, ensuring stable power and network performance.