OK, I know I'm opening up a can of worms here (I don't know if I should continue this in my previous post or start anew)
In my earlier post "gen. quest." I discussed how "I" terminated outside plant cables(burial/arial)and how I find grounds. Several replies said I was doing my grounds wrong. I did a "search" on grounding on came up with numerous post,some which frightened me and others that basically did the same as me.What is wrong with "Meter to AC volts, one leg of meter plug into right side of outlet, other leg touching metal water pipe or building beam, and if I read 120V I know that it is grounded" To me, this is an electrical ground.Why should I create a differnt ground with a better potential to ground? A lightning strike is always looking for least resistance to ground. By using my stated method am I not creating a path THRU my equip. yet if I create another ground (grounding rod) with less potential isn't that going to attarct the strike more (and hence THRU my equip)?
One other thing, gotten into arguments with others concerning path of ground wire. I have always done straight as possible, short as possible.Several co-workers, when grounding a data rack, would put a curley ( several wraps around a screwdriver handle)tail before attaching to rack and ground.
First, to address your question about the "wrapping a ground wire around a screwdriver handle" thing, I can't imagine that an extra foot or two of wire would really make much of a difference. Now that I think about it, that might actually protect the ground connection from being pulled loose if the rack moves slightly. So on that note, I kind of like that idea. Still, my preference would be to use #6 for that type of grounding; something that's a little tough to wrap into a tight coil.
Grounding conductors should always be connected to the nearest building grounding electrode, being a metallic water pipe, rod or metal building frame member. It's also important that all of these be bonded together. I have seen way too many instances, for example where an underground telephone cable terminates in an outdoor pedestal, being grounded to a separately-installed ground rod. This is where things can get dangerous because of the difference in ground potential. I have taken voltage readings between a local building ground and these separate rods that have been well into the double digits!
Always remember that all metal, whether it be pipes, racks, conduits or building steel must always be bonded together. Make it a practice to use #6 copper for your protector ground conductor and you will be all set.
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Ed
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How come there's always enough time to go back and fix it a second time?
Pretty much what Ed said. It's the difference in potential that will kill ya. As far as searching for a ground from the hot side of AC, like I said in your other post you'll find ground, but not necessarily a GOOD ground. Wrapping the ground around a screw driver?? For one if you can do that you're not using a large enough gauge for your ground. We did and I still do use a small gauge wire and wrap it around a screw driver like when connecting aerial drop to a paging speaker. This makes a fuse so if the drop gets hit by lightning the make-shift fuse will blow. Lightning likes to go in a straight line so by putting the wraps in it causes your fuse to blow out instead of the speaker. Believe it or not this works quite well.
So, If I take a piece of ground wire (I use #10 and/or #12 mostly)about a foot in length and put several coil type loops (almost like a spring)that will act like a fuse? Wouldn't the lightning strike "jump"?
I've never tried it with larger gauges, but I'd say the theory is the same. The old 22 gauge IW would blow at the corners if it had a direct lightning strike ( I have personally seen where it blew a hole through a wall into the next room). Personally I don't put 90 degree bends in my ground.
When you coil a wire around that screwdriver you are making an "inductor". An inductor will actually resist changes in the amount of electric current passing through it. If the current starts to increase, the inductor will generate a voltage that tends to oppose the change. Not a good idea for a ground, right? A few large loops near the ground bolt acting as a stress relief like Ed suggests is a good idea. Numerous tightly wound coils is not a good idea. Tight bends like "justbill" suggests to avoid, is also a good idea.
Wow, Twisted, you paid a lot more attention in science class than I did. I was thinking more of a stress relief solution for bonding connections. I figured just a foot or so of wire shouldn't make a big difference in a coil.
By the way, any word from your friend on the RCA Guide Plus issue?
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Ed
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How come there's always enough time to go back and fix it a second time?
Ed,
After that last post, I asked him again and he was going to check something for me. He then left on vacation. I'll let you know when he's back.