Electrician Coming Over What to Do?

Glen / Drubin: I ran into a situation where a gentleman had two separate grounds that were no more than about 10 feet apart from each other. The way that things were set up electrically, he had items from both grounds tied into the same system. He had mentioned to me that he was getting "whacked" when touching specific items within the system. I stopped by and took a look at what was going on. I was able to measure 40 volts on the chassis of some of his components due to the ground situation.

Once we tied the two ground rods together, the voltage dropped down to zero as we had minimized the differences in potential between the two grounds. The reason why he was only getting "whacked" on specific components had to do with how they were wired internally or the fact that he had a couple of pieces that were not oriented in the outlet for the proper AC polarity. Once we had gotten all of this straightened out, his components were no longer "hot" and the noise floor had dropped quite a bit.

I have run into other situations that were of similar nature, so i know this to be a somewhat "normal" situation. That is why i suggested keeping the ground rods as close together as is possible. So long as they are within a foot or so, i don't see a problem developing. If it does, one can simply strap the two together and be done with it. Sean
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There seems to be some confusion on isolated ground circuits. I am not implying you should add a second ground rod to obtain an I.G. circuit. Just tie your isolated ground to the ground bar at the meter if possible or to the ground rod itself. Rarly do I add a second ground rod and 99 times out of 100 I bond the two rods together when I do.

Glen: a TRUE "isolated" ground is just that, "isolated" from all other grounds. Having a ground path that runs directly back to the earth ground from the audio circuitry without tying into any other circuits would be called a "dedicated" ground. Obviously, this wording could still get us into trouble and keep us confused. While all of this boils down to a matter of wording and semantics, i think that we are standing on the same basic "ground" and have "common" thoughts about the subject : ) Sean
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I agree Sean but let's not get to carried away. We still need to tie them together at ground level or under the earth. We wouldn't want to go outside the N.E.C. requirments just to make are music sound a little better, Or would we?