The rules for grounding work much the same as the rules for anti-static protection on the bench - keep everything at the SAME potential. Tying antenna grounds to mains grounds means that you are not likely to see a deadly potential difference between antennas or equipment even if, in the event of a nearby strike, the whole system jumps hundreds of volts above actual earth ground due to the resistance of the ground connection. And, as others pointed out, there's the danger of a defective mains ground. From what electricians have told me, that is more common than we realize.
Years ago when water pipes were metal they were also bonded to the same ground. Of course, they provide their own ground, being buried, so bonding them prevented the possibility of another "independent" ground in the house. (Sometimes cold water pipes were used as *the* ground. In WWII vintage homes, I've seen the mains ground tied to a iron water pipe with a clamp. Of course, eventually the buried pipe rusts through and it gets replaced with more durable plastic pipe, and if no one ever upgraded the ground system...). AFAIK (I'm not a journeyman electrician) those grounds haven't been legal for years, but a lot of homes have been around longer than that. Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Phil Townsend Sent: Monday, March 28, 2011 10:13 PM To: Elecraft Reflector Subject: [Elecraft] Lightning in New Mexico The ground rod (#1) I placed just outside my shack/ house is about 16 or 17 feet from the meter/ ground rod that connects to the AC mains. So if I run a bunch of fat parallel wires that are bonded to BOTH ground rods that will be a good thing to do. (and required...by law)(knock on the the door ITS the ground police) As a matter of fact during the lightning season I disconnect the antennas from my gear when it looks like the Wx is gonna go south. (South,??? why not North???) Antennas consist of a 20 meter Gap vertical and nested marconi for 40m and 80m at 24 feet... Kinda like a dipole. These antennas run to an outside remote coax switch. I have beat into the dirt another 8' foot ground rod(G.R. #2) next to the outside coax switch and have installed a Poly Phasor on the output coax that goes into the shack and poly phasors on each of the coax cables from the antennas. All the poly phasor's ground lugs are connected to ground rod #2. (Each Poly phasor has its own wire going to ground rod #2) This remote coax switch and ground rod #2 are about 12 feet from the AC mains. If I understand correctly, I should also bond this ground rod #2 to the the AC mains ground rod as well???? But if I do that then those antennas will be connected to the grounds in the house via the AC mains ground rod????? This seems counterintuitive? I mean... now there will be the very real possibility of lightning in the house wiring??? Again Thank you for your help!!! Phil Santa Fe P.S... We get lightning almost as bad as Florida. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
