IPVMU Certified | 09/24/15 06:43pm
In general, if power is coming from a seperate source, the camera will not negotiate with the source to send power, even if available. If the camera does not need it, power is not sent.
No issues powering cameras seperately, but plugging them into PoE ports. No 'fried' cameras.
I know many cameras that specifically will take multiple power sources for redundancy. Some cameas will default to the first souce, others will always use a certain input as first priority. Then, if there is a loss of power, it can fail over.
I have never heard of a camera getting fried from getting 2 sources at once, as long as the sources are the right type (voltage, ac/dc)
There is no hard and fast rule on this.
The VideoIQ cameras could always handle PoE + 12VDC/24VAC "redundant" power with no issues, and at least back in 2008 era that was a moderately unique thing. I remember several integrators telling us stories about cameras that got blown up by being powered off of 12VDC and then someone plugging them into a PoE switch without realizing it.
I would think (hope) that more recent designs were better able to handle this, but it's really all in the powersupply design, so I'd recommend checking with manufacturers of the specific cameras you're using just to be sure.