Thread: Home Grounding
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Old 03-08-2011, 11:31 AM
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DaveInDenver DaveInDenver is offline
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Join Date: Jun 2006
Location: Larimer County
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Originally Posted by leiniesred View Post
I have a roof mounted antenna re-using an existing 2' satelite TV dish tripod.
This is exactly my VHF/UHF antenna mount, too! I will be putting a suppressor inline of the coax. This will be tied to my earth ground rod. But consider that a VHF length antenna mounted on the dish mount isn't really much higher or more likely to be hit than the dish itself was before.
The dish ground wire was attached to a spigot on the back of the house. Which would route a lightning strike into the house via the plumbing. sounds like a bad idea.
The only place a reliable ground can be achieved with household plumbing is at the point it comes in the house from the ground, before any shut-off valves. Any place beyond that the resistance and impedance back to earth might be too high. If it's a single point reference for your radios, it might be OK electrically to connect to a spot far from the earth path, but the difference between that connection and real earth could create a forcing voltage when you transmit (particularly if you earth reference your antenna rather than create an artificial ground with radials) or during an electrical event. RF burns really hurt...

BTW, only your /cold/ water pipes can be considered for grounds.
Can I install more ground clamps directly on the main ground rod like I have already done and still be National Electric Code compliant?
I'd have to check that, I think the NEC wants to see minimal connections because it's easy to create ground loops that can have significantly elevated voltages. In our dry climate it might be noticeable, but if it's raining or walking around in bare feet you'd very quickly know if you made a ground loop...
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