Do data center switch PoE ports require self-resetting fuses?

Data center switch PoE ports (PSEs) require a series resettable fuse to prevent short circuits in the powered equipment from causing port damage or power loss. For typical 48V/0.6A (IEEE802.3af) scenarios, the Etymotic SMD2920-150-60V (holding current 1.5A, withstand voltage 60V, initial resistance 0.8Ω) is selected. This device does not operate at 1.5A and operates at 2.5A in less than 5 seconds at 25℃. For PoE+ 30W (0.8A), the SMD2920-200-60V (holding current 2.0A) is selected, and for PoE++ 90W (1.8A), the SMD2920-300-60V (holding current 3.0A) is selected. A TVS such as SMCJ58CA (VRWM=58V) is connected in parallel to protect against surges. In actual testing, during a short circuit fault, the PTC operates within 3.2 seconds to limit the current to within 200mA, and automatically recovers within 2 seconds after the fault is removed.