What Should You Do If the PoE Switches Fail to Supply Power?

There are many power supply methods for powered devices (PDs), including centralized power supply, independent power supply, 220V AC power supply, and PoE power supply. Among all the different occasions, PoE switches are more and more frequently used due to PoE cabling simplicity. But there are also problems. One of the common issues is that the PoE switch suddenly fails to supply power. What should we do at this time? This post will introduce details for you, we can rule out one by one from the following aspects, let’s take a look!

1. When PD (such as AP, camera, IP phone, etc.) is working abnormally, first confirm whether there is power supply abnormality by the working indicator of PD and the log record of the switch. When the working indicator of PD is always on, it means the PD is powered on. When the PoE power-off record is not visible in the switch log, it means the PD is not powered off, and such problems may be caused by port negotiation or AC management.
   
2. Confirming the environmental factors, such as whether the network cable is faulty or the PoE switch is poorly grounded. When the PoE switch begins to power up, it needs to detect the PoE class the PD. If there is external interference, it may affect the judgment of detection, resulting in not being able to power up the PD, please ground the PoE switch reliably.
   
3. Confirming whether the switch and its power modules support PoE function and whether the power is sufficient.
   
4. Collecting the field information of the problem device and PD. In addition, you also need to understand clearly the specific model, required power, supported standard (802.3af/802.3at), etc. of the PD.
   
5. To determine whether the PD is a standard PoE device. If it’s a non-standard PoE device but a 48V powered device, you can try the following methods.
   A. Switch(config)# power inline enable
   B. Switch (config)# power inline legacy enable
   C. Switch (config)# power inline high-inrush enable
   D. Switch # show power inline
   
6. Confirming whether only part of the PD module is not available for power supply. If it is confirmed that only part of the module function is not available, after enabling LLDP, configure the following command and then plug the network cable or re-enable PoE function to verify.
   Switch(config-if)# lldp tlv 8023-org-specific all
   Swicth(config-if)# no lldp tlv med all
   
   Note: The method mentioned above is a general solution. More complicated problems need to be solved case by case . If it has not been resolved, customers who are using NADDOD PoE switches can directly call us or leave a message on our official website www.naddod.com for consultation.