What problems can a ground loop cause?
Ground loops are a major cause of noise, hum, and interference in audio, video, and computer systems. Wiring practices that protect against ground loops include ensuring that all vulnerable signal circuits are referenced to one point as ground.
Does Poe have ground?
Straight to it, the POE injector has a terminal on the side labeled “ground”. It is connected internally to the metal-clad RJ45 sockets on the input and the output end of the injector. There are also metal Rj45 sockets on the AP itself. No ethernet cables were supplied.
Why do I have different ground potential on my Ethernet cable?
For reasons that only an electrical engineer can explain fully, having multiple points of ground can cause ground potential differences in your cable system. Those ground potential differences are then literally looped back as common mode voltage, and get injected across your Ethernet cable.
How to avoid or fix a ground loop?
Quite often I get questions about how to avoid or fix a ground loop situation when using Ethernet cable. It is great that people are reading Shielded vs Unshielded Cable. That is the starting point. Knowing you could run into this issue is half the battle. Fixing or avoiding it is the other half.
What’s the problem with grounding over a distance?
Grounding is often misunderstood to be the end-all solution for connecting things together. However, in most cases, even on short runs, grounding adds more issues than it solves. The issue with sharing a ground over any distance is you are assuming both ends are at the same ground potential.
What happens when you run a cable through the ground?
As such, when you run a cable that includes ground between them, there will be a current running through that ground. Moreover the common ground becomes the current return path for your signal. That means you are actually adding noise into the ground line.