Great answers Gs5556 and Jea48! Really learned alot! Thanks.
Maybe you two electricity mavens can help me on a question I have regarding grounding, specifically the safety equipment ground found in the 3rd prong of a properly grounded ordinary wall power outlet.
Is there a way to measure the relative effectiveness of a wall outlet third prong grounding system versus another wall outlet's ground versus a copper rod sunk specifically for grounding purposes of my system? What I mean is that when I took a separate 8' copper grounding rod with a 10 ga. wire attached, and sunk the rod about 15 feet in the ground and then ran the 10 ga. wire through my home's siding and used that as my star-grounding point/source, my system was supremely quiet. Now that I have moved my system to the other side of the house, the grounding rod/wire isn't available anymore, so I am using the wall power outlet's 3rd prong ground. Now the system sounds MUCH dirtier, and it is basically impossible to measure AC voltage on the chassis using this grounding source. It just doesn't register on the DMM. When I had the old grounding system with the copper rod sunk 15 feet into good ol' mother earth, the system was so quiet and the voltages on the chassis so easily ascertainable, that there must be significant differences in grounding potential between the two manners of grounding. A polarity and ground tester, however, shows the wall is correctly wired, including ground. Further, none of my equipment is third pin connected, with the third leg either non-existent (i.e., the two prong plug of my Sony CDP) or defeated (as in my CODA CSi Limited integrated amp.)
A friend said the difference is the relative masses of the ground planes (i.e., more copper of higher purity means more effective grounding, assuming proper placement in the earth.) He said the copper rod I sunk is probably bigger, heavier and more immediate than the house's third prong grounding system, and this accounts for the difference. Does this make sense? On the other hand, the wall outlet 3rd prong grounding connection is supposedly connected to my cold water pipes, thus allegedly tying me into the vastly enormous steel piping system of my water supplier (I live in the mountains north of LA.) Which should be better in theory? In your experience?
Would cleaning the 3rd prong female receptacle possibly make a difference? It could be oxidized, and we all know how oxidized RCAs clog things up and destroy sound quality. Might this also apply to grounding connections as well? I tried using alcohol and a pipe cleaner brush, but it made no discernable difference on the DMM reading for voltage on the chassis. Should I be using a different cleaning agent? Will this make any difference at all?
Again, I think the most important question is whether there is a device to test the relative effectiveness of a grounding system? How do they work and do you know where they are available at a reasonable price?
Sorry for all the questions, but this is really annoying me. I just set the system up yesterday and went to check proper equipment polarity using my DMM and the 3rd prong ground as true ground. I couldn't get a reading of any AC voltage on the chassis, or more accurately, the signal ground plane. This has never happened before, with my RadioShack DMM easily showing the relative voltages between the two plug polarities whenever I have checked for same in the past. However, this is the first time I've used the 3rd prong of the wall outlet as true ground for the DMM.
Oh, yes, I almost forgot. I really don't want to dig up the old grounding rod, or sink a new one, if at all possible. I'm older now, with severe arthritis.
Thanks for any assistance you can offer.