Re: Lightning protection for outdoor ethernet Grounding rod questions etc..

Michael Kennedy wrote:
I have a ethernet cable that runs from my house to an out building at my house. I live in Florida and we have a real problem with lightning around here. I plan on using a a TII telephone lightning arrestor on each end.. I'm talking about the kind that the telephone company puts on the side of your houese with the gas arrestors inside.

I think this will work but I have one problem.. I don't know if a ground rod at the out building will be enough to ground a lightning strike. The building doesn't have a ground rod right now but I was planning on putting one in for this..

How do you get a good ground with a ground rod. I have tried driving one down but when I ohm it there is always a lot of resistance vs the power company's neutral / ground. I was told that a good ground rod will have about 15 ohms of resistance between the rod and the system ground.

I would just hook this arrestor up to the out building's ground wire, but the ground and the neutral are tied togeather and I don't think there is a very good ground out there because the ground on the CATV wire will shock you if you touch it and a ground in the building out there. On the voltmeter it reads about 3v between the catv wire ground and the bldg ground.. So I think my ground is overloaded or has a bad connection at the breaker pannel.. It has 2 legs of 120v and one neutral. There is no seperate ground wire.

Thanks for any advice / help..

- Mike

I would (did) go underground for this application. (Run a ground wire along with the Cat5).

I had the same setup: outbuilding with house around 75' away. I buried a 2" plastic conduit when I had my water line replaced; but one wouldn't really need to bury it as deep as I did. A foot or so would be sufficient for low voltage stuff...not so difficult in Florida's sandy soil...a real BEAR in Tennessee clay. I ended up running two cat5's, a 12 gauge ground wire and RG59. I used on cat5 for networking, one for three phone lines and the coax (of course) for cable. I actually had originally run thinnet coax in there, but there was plenty of room for everything. I had 360 degrees of bends in the system, so installed access points where it came out of the ground.

I put in a nylon pull line when I installed the conduit, with plenty of slack at both ends so I could pull either direction. Total cost for plasitc conduit, connectors and glue was less than $100, IIRC. Alas, I sold the property for development. I wonder if they dug up my conduit....?

I'd like to do the same at my home, but I'm looking at bedrock less than three inches under the grass in places along the intended route.

jak

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