PoE switches require no power supply

Yes, PoE switches require an external power source to operate, even though they can supply power to connected devices via Ethernet cables.How PoE Switches WorkPoE (Power over Ethernet) switches are network devices that transmit both data and electrical power over Ethernet cables to connected devices such as IP cameras, phones, and wireless access points . While they can deliver power to these devices, the switches themselves cannot operate without their own power supply. They typically receive power through a standard AC connection or, in some cases, a DC power source .Power RequirementsThe internal components of a PoE switch—such as processors, memory, and PoE circuitry—require electricity to function. The switch then allocates power to connected devices according to its PoE standard (IEEE 802.3af, 802.3at, or 802.3bt), which defines the maximum power per port, ranging from 15W to 90W . The total power available for all ports is called the power budget, and the switch must be powered sufficiently to meet both its operational needs and the power demands of connected devices.Misconceptions About Self-Powered SwitchesSome users assume that because PoE switches can supply power to devices, they might not need a separate power source. This is incorrect. PoE switches cannot draw power from the devices they serve; they must be independently powered via AC adapters, inline injectors, or centralized PoE power systems . Even small unmanaged PoE switches require an external power source to function.Practical ImplicationsWhen deploying a PoE switch, it is important to:Ensure the switch is connected to a reliable power source.Verify the total power budget can support all connected PoE devices.Consider backup power options if network uptime is critical. In summary, while PoE switches simplify network deployments by powering devices over Ethernet, they themselves always require an external power supply to operate .