new metal ground clamp, limestone screeding around lead pipe & new brass valve

I finally got a new main water shut-off ball valve installed in the same position as the old handwheel- type leaking valve just before my water meter. Before I patch notched studs and drywall and paint all around it, and then install a ceramic floor tile there are a couple of issues I need to be considered about possible corrosion and re-positioning issues. The plumber may have mentioned that the pipe coming up through the dirt, then through the slab is "lead". I looked at it. Its got green corrosion, and golden colour apparent chipping through it. I think its copper. Currently, other than it, the only thing other than copper/brass is the one remaining good ground wire clamp. And my limestone screeding idea.
I need to cut off the old main electrical-panel ground wire clamp which is now attached even before the valve. Its currently in dirt, which is below the concrete slab level; the new installed valve itself will be surrounded by tile. The clamp on the pipe itself that comes up through the ground as well as the connection screw eye on that end of the twisted steel wire which completes the circuit (possibly if the water meter needs to be disconnected) have both corroded through and there is nothing to clamp to:to. I am not sure where I am going to place the new electrical ground clamp on the street side of the meter. Probably one that looks the same as the one on the other side. A (o)+ clamp with screws on either side to clamp the wire directly to the copper supply-line pipe, with a slot with screw to clamp the bare twisted wire into +. Its on copper pipe. the Horozontal pipe immediately downstream from the water meter. So I'll put one on the other, closet to the street side, of the water meter. This will be after the new valve, but the only other option is below the soon to be tiled floor!
I also want to fill the gap in the concrete slab (a 6" x 6" void with square edges right down into the dirt to China) so I can cut to fit a ceramic floor tile. Nobody will even put too much weight on it, but it is the last of any areas where the tiles will need to be installed right up to the edges of the floor. I won't thinset the screeding, just the outer parts of the tile leveled on the surrounding concrete slab. Hmm....a humped screeding.
These questions are all about dissimilar metals, water , and possibly electricity.:
Q1 Proposed location and probable steel material of a soon-to-be-purchased new electrical ground wire clamp attached directly to horizontal copper supply-line pipe after the (Vertically installed) new valve (embedded in tile w/ gap) but just before the water meter.[steel on copper]. There seems to be no problem with corrosion on the original/remaining location, but I am also changing the location, because of the tiling needed.
Q2 Spreading and leveling limestone screening into the dirt hole in the concrete slab, which will pour and pack loosely right up to the main water supply line (I think its copper, but lead it may be ). I think the very lowest extent of the new brass ball shut-off valve is gonna be slightly above the leveled screeding line, about half way up the height of the ceramic floor tile itself.
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I bought an identical brass ground clamp at HD, which they call a wet clamp, and sell beside the steel (dry) clamp for a buck and a half more. I am not planning on changing the other original steel one. Don't know what I'd do if they should be the same. I see no reason why I can't just put the new one after the new ball valve, befor the water meter. I guess I could put it on the valve itself. In fact the whole thing is a bit ridiculous, but better than going back. Is it something to do with by-passing the water meter itself? I assume electricity will flow through a brass ball valve into the earth?
So its down to the limestone screeding. It sets up pretty hard when after it gets wet, which it probably will from under. I have reconsidered and decided to put a rubber wrap / flexible gasket around the pipe anyway, before I pour, spread and pack the screeding. This may not negate any or all possible extreme corrsosion issue(s), but will isolate it from any forces or shock at least. I am still curious if there are corrosion concerns. Or even type of rubber issues.
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btw, I have newsfeeds.com for a news server. In the last week or so I have lost the newgroups rec.woodworking and alt.support.diabetes. Possibly others, such as this. They may even have disapperred/reappeared/even re-disappeared. I am not sure what is going on. If you read the std. sig at the end of this post you will see one of the reasons. I'm not sure if its in my pooter only, or wot. Would anyone check the wreck and let me know whats going on, either here or by e-mail to me.
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Limestone is alkaline, the opposite of acidic, on the pH scale I have put lime on acidic soil, where the grass didin't grow under the cedars, and where the moss was. It is not chemically neutral. Its got a lot of uses, just not sure if this is a good one. Don't know what the pH of the dirt is.
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"ANSI/NSF 61: Drinking Water System Components-Health Effects. This is the health standard for all plumbing products and materials that come in contact with potable water. Copper water tube, copper fittings, and copper and brass plumbing valves and fixtures are covered by NSF Standard 61. The Standard specifies that copper tube be evaluated at a pH of 6.5, rather than at the pH of 5 and 10 for other material types."
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"Copper tube (Alloy C12200) is Certified by NSF to ANSI/NSF Standard 61 for public water supplies meeting or in the process of meeting the EPA Lead and Copper Rule (56FR 26460, June 7, 1991). Water supplies with pH less than 6.5 may require corrosion control to limit copper solubility in drinking water. "
from http://www.nsf.org/business/newsroom/plumbing99-1/coppercert.html
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& copper is the 2nd best e-cal conductor, 12th Materials Handbook. Thats pure though.
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so, you're saying its ok
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