Passive POE 24V, how can it damage a non POE device
If PoE is passively injected without detection, it usually means that the supply voltage is applied to pins 4&amp;5 and the supply return to pins 7&amp;8.
If the device has DC coupled common mode termination on the cabling side of the Ethernet transformer, it basically means the transformer center taps are connected with 150 ohms of resistance, and yes, it will be damaged from applying PoE passively.
Devices that will tolerate passively fed PoE have AC coupled common mode termination where capacitors isolate the DC path between pairs.