2 electrodes lets you off the hook for NEC, but not with the lightning hurling gods. New Mexico code has actually dropped the 2 rod rule as well, you have to install a Ufer ground in all new construction there. WIth dry rocky soil, your impedance with 2 rods can still be hundreds of Ohms.
The Amprobe's lowest range is .025 to .25 ohm. The lowest reading I've seen was .95 ohm on a commercial building in Hawaii. Ray On Sep 15, 2010, at 6:25 AM, Darryl Thayer wrote: > If you are doing Off Grid is it enough just to drive two ground rods? and > make a connection between them? Also what is the lowest Ohm reading your DGC > 1000 meter can read? > Thanks > > --- On Wed, 9/15/10, R Ray Walters <[email protected]> wrote: > > From: R Ray Walters <[email protected]> > Subject: Re: [RE-wrenches] Lightning protection (was Delta LA's) > To: "RE-wrenches" <[email protected]> > Date: Wednesday, September 15, 2010, 12:34 AM > > Hi Dave; > > I bought an Amprobe DGC 1000 for around $1100. It takes seconds to get a > reading, without taking any connections loose or shutting off power. > There are much cheaper units (3 point fall of potential type) to be had for > under $500. They take more time, but also would be better for off grid > measurements. > > R. Walters > > On Sep 14, 2010, at 8:04 PM, Dave Palumbo wrote: > >> What Ray Walters said was the truth. Resistance to ground should be very >> low. How many dollars is that tester you use Ray? We don’t own one. On the >> wish list. > > -----Inline Attachment Follows----- > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org >
_______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
