His reinforcing steel inside his driveway is probably way far out of the realm of Ufer grounds, due to it being small gage conductors. Aside from the great difficulty of boring into the concrete and adequately bonding to those wires, I wouldn't try this anyway out of concern that the current density during a major lightning hit might be sufficient to produce widespread cracking of the concrete.
If it was the sole ground, or the major part of a ground that might have to handle a direct hit, I wouldn't use it.
If it were simply something to augment an already good lighting ground or improve an RF buried ground system, I would not worry one bit about using it.
Now I'll have to go re-read and brush up on Ufer grounds, but as I remember, his driveway setup would be woefully inadequate for the possible current levels involved in the event of a direct lightning strike. Personally, I wouldn't go there. A concrete drive would be a little pricey to replace, especially considering the relatively small prospective gain in HF ground quality he might see by connecting his radial field to it. I'd much rather connect *over* that drive using strategically sawed grooves and lightly concreting in a few wires at the surface in a few places- this assuming he has somewhere to go on the far side of the drive with those wires anyway.
Again, it is only a problem if that is the major part of the ground. If it is incidental and only an additional improvement, and the rests of the system was OK without it, I'd use it.
I've tied my heating ducts and water pipes in, in the past. It does take some common sense in whether it is worth the work, and knowing if the rest of the system is large enough that it creates no hazard.
I know a ham who thought his well pipe might make a dandy addition to his ground radial system. He connected it, and eventually had to replace a 600 dollar well pump after a strong lightning hit on his property. This driveway question reminds me of that. Properly designed Ufer grounds, fine- but I sure don't want to invite lightning hits to dissipate through anything concrete on my property. My two cents (two dollars, adjusted for inflation...)
That is just asking for problems. Many well pipes are only metal at the head. Below the head or cap, they are often plastic. Well casings are almost always plastic today. The only guaranteed metal paths are the wires to the pump, even if it starts as metal at the top. Also, the wires are outside any metal pipes if metal pipes do exist, and lighting travels on the outermost surfaces. That would be the wires.
The well is nothing like concrete remesh. I would not bother connecting to a unknown rebar system, but if I knew it was bonded or remesh (screen) I sure would use it. Not as a primary ground, but to augment an existing pretty good ground in a direction the existing ground might not go.
I remember a few people who had houses in the way of a full system, and they ran the radials right under the floor joists. They used heating ducts, fences, water pipes, and everything else they could. The more they used, the stronger they got.
73 Tom
_________________ Topband Reflector Archives - http://www.contesting.com/_topband