I want to replace the router/modem Comcast with a high quality for streaming

@mitch2 Yes, we do know.  Fiber optic cables, lacking in any metal components, cannot transmit an electrical surge from point to point.

For this reason I use a fiber converter between the cable modem and Wifi router.  There are still potential paths through the AC wiring, but that's dealt with by a UPS with surge protection. 

The other place where Ethernet can pick up a surge is if the cabling is long.  It acts as an antenna, and the longer the cable the higher a surge voltage can build up.  Of course, whether this matters to you depends very much on where you live.  First year I moved here we had several strong lightning storms which took out multiple neighbors cable modems, and a laptop of mine (via the power cord).

Have you considered a fiber media converter set up?

I added a switch right before my DAC and put the media converter /streamer bundle from  Small Green Computer. It changed my entire listened experience.  
I’ve recently upgraded to their top tier but do have the bundle in a box.  If your Interested or have questions let me know.  It basically cleans up all the “noise” from your router and give a pin quiet signal to the DAC 

I have Comcast. I’ve always used my own equipment. Currently using

Arris SB8300 modem and Asus RT-AX88U Router 

Hi @erik_squires following up on 

Fiber optic cables, lacking in any metal components, cannot transmit an electrical surge from point to point.

For this reason I use a fiber converter between the cable modem and Wifi router.  There are still potential paths through the AC wiring, but that's dealt with by a UPS with surge protection. 

so this would stop electrical surge into the WiFi router?  But only into the WiFi router?  Are you using Ethernet cable from your modem to your audio gear?

I am just wondering why only protecting the WiFi router..or is it because you have fiber coming into an ONT prior to your modem so that is already not going to get hit?      Thanks!

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.