Hi @fastfreight
The path from lightning surges to Ethernet connected devices like a TV or streamer or PC is like this:
Outside copper cable --> cable modem --> Wifi router (which also has an Ethernet switch) --> All Ethernet connected devices
So if I can prevent a surge from making the jump from the cable modem to the wifi router then I’ve protected most of my Ethernet connected devices from Ethernet based surges. I also use an outside gas discharge tube on the coax as well as an Ethernet isolator at the end of my two long Ethernet runs.
Of course, this has nothing to do with lightning surges which can occur in the power lines. For that I use a whole house surge protector in combination with point of use surge protectors made by either Tripp Lite or Furman, or when UPS powered have to rely on the surge protectors built into the UPS.
In my mind, it’s not just about protecting the Wifi router (which is a giant PITA to replace) but about protecting anything I have that relies on copper Ethernet cables. I use a lot of Ethernet on streamers and PC’s so the worst case scenario for me is to lose a lot of devices all at once because lightning came in from the cable Internet provider.
Any copper wire that goes from outside to inside can be a lightning source that once inside can jump to any other copper connected device. Antennas should also be surge protected. I had a DirecTV antenna and receiver which would fail due to wind induced surges (electrons would build up on the antenna and build a charge). Once I put a surge protector on it the problem went away.
An Ethernet connected device like a music streamer or PC may have 2 lightning paths, one from the AC and another from the Ethernet and we have to protect both.