So, what is a ground loop?
A ground loop occurs when there is more than one “ground” or “earth” between two pieces of equipment. Because the two pieces of equipment have multiple ground paths, loops (circuits) are formed in which current can flow. The current flowing through this unwanted circuit in the CCTV system can have a devastating effect on the system’s performance. The current flows through the shield of coax types of cable and instead of “dragging” any interference (usually 50Hz mains hum) down to a “true” ground at the receiving end of the cable, it actually picks this interference up (in its ground loop antenna!) and carries it to the sensitive inputs of CCTV equipment such as DVRs, Quads and Switchers. The DVR, quad or switcher simply interprets this “interference hum” as part of the intended video signal entering the equipment and displays it on the monitor as a rolling “hum” bar. By carefully using good CCTV power supplies you will minimize ground loops but if they still exist then a device that bl
