When you install a surveillance camera system, you will now and then end up with these types of unpleasant lines over the screen. Usually the primary thing you end up doing will be return the video camera given it appears to be malfunctioning, only to discover it works fine while in the store or that the replacement does the same thing.

The normal cause of this is an ground loop, in which a voltage variance has occurred on one side of your coax cable to the opposite end, with respect to earth.

They are able to be seen as varied patterns on the screen or even result in a DVR to not record due to a distorted synchronisation pulse. Below a few of the effects you might notice.


There's really no point accusing someone for these since they are unforeseen as to if they are likely to arise but they are more prevalent where the security surveillance camera is positioned in an area which has a different grounding point to the DVR or monitor. For instance a security camera pole is not earthed at the same point as the structure in which the DVR will be. The fact is you could get earth loops in many other applications which include a buzz in audio or a data corruption in a network.

There are a few strategies that should lower the probability of having an ground loopbut not one will prevent them.