CCTV Ground Loop or other voltage issue?

[wick1144retired]

In the past case, it was caused by the power supply (plug in type transformer)

[zbang]

Ground loop isolators. I've tried one with no luck. It just seems like that is a lot of voltage. I've had other ground loop issues in the past, but that was reading DC voltage, not AC.

I'm going to guess that the old system isolated the feeds and the new one doesn't. In that case, you need to isolate all of the cameras. Have you tried just one camera with the isolator?

It's possible that one or more of the power supplies has a problem. Anyway, divide and conquer- try one camera at a time, check the power supply outputs to see if they're all correct (and floating from chassis ground), move one PS to another camera, etc.

It's also possible that there are a couple of cable faults out there, check to see that the shields are really isolated when disconnected from both ends. Unfortunately, I think there's going to be a lot of running around disconnecting things and testing them.

[GrayHair]

zbang pretty much has it. Newer equipment is almost always more sensitive, explaining why there were no problems with the old DVR. Connect one camera at a time looking for indications of a ground loop. Isolation transformers is the way to go. N transformers will be a BUNCH cheaper than N*2 fiber modules.

[wick1144retired]

Well, to make a long story short, I eliminated the voltage by running power from the head end to the cameras, putting everything on the same circuit. As far as the cameras go, I had to replace the cameras. Now everything is fine. I am curious if the voltage on the video cable caused the cameras to fail. Thanks for your thoughts.