So I have a camera and a siren, both are driven by a PoE connection. I have a PoE switch, but it only can provide enough power to drive the siren. So what I want to do is hook both the camera and siren into the PoE switch, but run the connection to the camera through a PoE injector so it gets enough power. In this way I can run the camera and the siren with 1 PoE switch and 1 PoE injector rather than 2 PoE injectors and 1 unpowered switch.

Will I blow up my PoE injector if I use an already powered ethernet connection as the data input connection to the camera's PoE injector? This seems like a pretty unusual set up so I just figured I wanted to ask before I try it out and potentially fry my PoE injector.


You will need provide specific details, model numbers, 802.3af/at POE or passive POE, 10/100 Ethernet or gigabit Ethernet. If it is standard 802.3af/at POE you shouldn't have a problem. If it is passive, particularly GB passive your results might vary.

  • Okay just looked it up and both the PoE switch is 802.3af compliant and the injector is 802.3at compliant so I'm going to give it a try. Thanks!
    – Adam O.
    Feb 16 '18 at 18:56

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