Normally when grounding electrical and stakes we drive the rrod , connect the ground strap having sanded the connection and clamp securely then spray with a special metalic paint , been doing this a long time with good success.
________________________________ > To: Repeater-Builder@yahoogroups.com > From: gascha...@comcast.net > Date: Tue, 30 Jun 2009 23:23:43 -0500 > Subject: RE: [Repeater-Builder] Re: DC Ground Lightning Protection / Concrete > Electrode > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Actually galvanized and copper plated > ground rods should not be mixed in any ground system. Electrolysis will > deplete > the plating. All ground rods in any ground system are electrically connected > to > one another. > > > > > > > > 73 > > > > Gary k4FMX > > > > > > > > > > > > > ________________________________ > > > > > > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Glenn Little WB4UIV > > Sent: Tuesday, June 30, 2009 7:53 > PM > > To: Repeater-Builder@yahoogroups.com > > Subject: Re: [Repeater-Builder] > Re: DC Ground Lightning Protection / Concrete Electrode > > > > > > > > > > > > > Another way to pass a ground cable through > concrete is via a PVC pipe. The last thing that you want to do is run a ground > cable that can carry lightning fault current through concrete without > isolating > the cable from the concrete. > > The fault current will rapidly heat the ground cable, causing it to expand, at > the same time vaporizing the water trapped in the concrete. The result is a > violent steam explosion. The results could be the total fragmentation of the > concrete. > > > > MIL HDBK 419 is available for download. This is a military manual that > addresses grounding. > > Another very respected guide is Motorola R-56. > > > > Galvanized ground rods should only be used at the guy anchor points. > > Copper plated ground rods should be used around the tower base and the > building > with all bonded together by exothermic welds 18 inches below grade. > > Ground rods are to be placed no closer than twice the length of the rod. > > Any closer and you are wasting your funds. > > > > YMMV. > > > > 73 > > Glenn > > WB4UIV > > > > At 10:07 AM 6/30/2009, you wrote: > > > > > > > > > > > > > I'm going to disagree with the > following posting: > > > > If the tower is bolted to galvanized pipe that is embedded in concrete of > > which a significant amount is in contact with soil, you have a > > "concrete-encased grounding electrode" which is hard to improve upon. > It is > > not likely that a ground rod would be worthwhile, since damp concrete > > (concrete in intimate contact with soil at grade level) is a fairly good > > conductor, and such a footing or foundation has hundreds of times the > > surface area of a ground rod. > > > > I have > read Ericsson specs for cellular tower installation in that disagrees with the > previous statement. > > > > Standard > concrete without conductive enhancing materials can crack, pop or crumble if > subjected to a direct lightning strike if ground rods are not properly > installed. The water contained within the concrete will vaporize > instantly causing the concrete to fail. > > > > There > are types of conductive concrete mixes or additives that can be used, but the > most common practice is to use a ground rod from each leg with a copper wire > bonded to each tower leg. > > > > Our > mfg building at work is made from steel I-Beams into concrete. I have > noticed each I-Beam has its own ground connection. The strap is bolted to > the beam about 1" above the concrete, then disappears into the concrete, > and suspect there is a ground rod going into the soil beneath the concrete > piling, but thats just a theory, as I dident see it before the mud was > poured. > > > > Ed > N3SDO > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _________________________________________________________________ Get the latest news, goss and sport Make ninemsn your homepage! http://windowslive.ninemsn.com.au/article.aspx?id=813730
