It has been a long time since I have looked at a lightning arrester, but essentially they shunt large pulses to ground. The surge protectors I have dismantled after a strike have component that looks like a ceramic capacitor. I believe the old antenna arresters used for long wire radio antennas, which I made when I was young (about 45 years ago) for short wave receivers, had a gap, which lightning would hopefully jump, between the circuit to be protected and the ground lead. Obviously, cable TV wire is shielded. After thinking about it some more, I think the clamp used for cable TV lightning protection, simply connects the shield to the wire running to the grounding rod.
If it were me, I would stubbornly find a way to run the network cable (and telephone wire) inside, and that can be doneÖ with some to a lot of difficulty, Iím sure. I have snaked a lot of wires in very old buildings. If I had to run it outside, I would probably put it in a grounded, metal conduit. But donít assume that I am an expert on lightning, that I endorse this procedure, or that it is guaranteed protection for people, computers, buildings, etc. against lightning.
I would also run a second CAT 5 cable in the conduit for the telephone wiring. This would provide additional pairs for growth. I just installed a CAT 5E cable running about 130 ft though my house, from a small punch-down block near where the phone lines come into the house to a wall plate with four RJ-11 jacks screwed to the (wooden) wall, in my new office/shop, for the three phone lines we presently have installed. I also ran the lines from the Telco termination outside of the house to the punch-down block just inside with a single CAT 5E cable. I have been using the lines for almost two weeks. The data line I use for various MODEMS, etc. works exceptionally well. The voice lines are absolutely clean. I plan to run two more lines like this one to the other two offices in our house, except one of the jacks will be a CAT 5E jack for still additional network lines. Yes, we have three people living here and each of us is setting-up a home office.
You may also want to consider putting a lightning rod on your house. I understand that a properly installed lightning rod system will work to protect a house 90% of the time. I guess you get fried the other 10% of the time.
Today, I found a device for protecting networks, but it doesnít appear to be designed for outdoor use. See http://www.elect-spec-transformer.com/netwrk_z.htm.
Other relevant links:
Maybe someone, an expert, in academia, etc. will pick-up on this thread after the search engines find it and contribute some knowledge. That would certainly be appreciated. As far as I am concerned, this horse has pretty much been beaten to death by quite a few Forum postings. Good luck! Larry