What is a ground loop
What is a ground loop
A ground loop is a condition in an electrical system that contains multiple conductive paths for the flow of electrical current between two nodes.
Ground loops can result in signal noise, communications errors, or a damaging flow of ground current on long cables. Most often, ground loops do not have drastic negative effects and may be unavoidable
Common Causes
The drain wire of a shielded cable is connected to the local ground at both ends, and the ground is already being carried by a conductor inside the cable. In this case, two wires, one on either side of the cable shield, are connected to the ground nodes at both ends of the cable.
A long cable connects the grounds of two electrical devices, and the mounting structure or grounding rod also directly connects the grounds of each device to the local earth ground. The two paths, in this case, are the connecting cable and earth itself.
When electrical devices are connected to a common metal chassis such as an instrument tower, the structure can create a ground path in parallel to the ground wires in sensor cables running over the structure.