IPVMU Certified | 03/01/15 04:15am
There are a number of possibilities here, from high-voltage EMI, to rapid flickering effects seen in the image.
Preventing EMI in the cable is best avoided by running the data in raceways, trays or with hooks that are separated from high-voltage cables by 8" or more. In the context of most installs, this is not very difficult. Basic steps like not lazily laying cable runs atop light fixtures usually prevent problems.
The 'flickering' problem can be mitigated generally with camera settings. The flickering is caused of the frequency of fluorescent light ballasts vs the shutter speed of the camera. This is not a very common issue, but the 'Flicker Free' setting in many cameras will disrupt the sync very slightly to avoid it.
As Brian says, your main concern with fluorescent lighting will be the flicker... I've seen UTP cables draped across the tops of fluorescent fixtures without causing issues; twisted pair is designed specifically to reject EMI.
I've only ever seen one model of IP camera that had issues with fluorescent lighting, and that was a HIK model re-sold under the 3xLOGIC brand some years ago... with that though, the interference on the picture looked like the EMI was actually getting straight to the camera innards; EMI into the network cable would only cause connection failures, not noisy picture.
I have also heard the above referred to as 'banding' rather than flicker. But the cause/affect is the same. This may not even relate to actual EMI (as Matt mentions), but rather a consequence of the exposure/ballast speed syncing up
As mentioned above changing the shutter speed should help resolve it...but most manufacturers have a 'Anti-Banding' or 'Anti-Flicker' mode that auto-magically fixes it :).