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Discussion Starter · #1 ·
To be more specific, what is a fair price for dedicated, 20 amp, 10 guage wire circuits with hospital grade outlets? I need to call my local electrician this week to get an estimate for installing 2-4 dedicated lines in my HT. FWIW, I live in Fort Worth, Texas...
 

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Before you do, why don't you give Jim Aud a call over at PAD. He's down in your neck of the woods. Jim might have some suggestions on how to make the outlet a little better.



Alan Maher
http://community-2.webtv.net/audionutak
 

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Discussion Starter · #3 ·
"Before you do, why don't you give Jim Aud a call over at PAD."


Alan, who is Jim Aud? What is "PAD"?
 

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PAD is better known as Purist Audio Design. Jim is a leader in the cable business, and an expert in electrical design by computer modeling. He would be more familiar with your local code then I would be. Down in your area, he's one of the few I highly respect when it comes to this industry. I'm sure he'll be able to advise.



Alan Maher
http://community-2.webtv.net/audionutak
 

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I had 3 20A dedicated curcuits installed on my second floor with individual ground rods for each circuit. The electrician charged me $400 but I think he spent about twice the time he had planned on. Pounding in the ground rods took almost as long as installing the circuits and could easily be left out of the job spec.
 

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Your electrician installed individual ground rods for each circuit? Something about that does not sound right.


Isn't there a chance that a differential in the ground can be created due to differences in potential thereby inducing a current?


Receiver plugged into one circuit, DVD plugged into another circuit, each with a different ground. Connect the DVD to the receiver and a current is created across the connecting wire due to a possible differences in grounding potential. The current can damage the equipment.


The only reason this comes to mind is a few years ago I renovated my bathroom and the GFI kept tripping. We found the problem was that there were two circuits to the room, each with a different ground. The GFI sensed the difference and popped.


May want to ask your electrician if this is a potential problem.
 

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I have nineteen dedicated 20 amp 10 guage wire circuits for my home theater room, into their own electrical panel to their own copper ground rod, which is then tied to the house ground - this is required both for Code and safety.


I have been told many times of the "potential" problem in using multiple grounds which Carl Holt mentions above.


Knowing Carl Brinkman as well as I do, I suspect that Carl probably ran

4 guage copper wire from each copper ground rod back to the house ground, which I think but am not sure (I'm no electrical expert, I ask others)

would satisfy Code and safety. Whether using more copper ground rods like this might be more likely to cause a "potential" problem, that's another story and I don't know the answer.


I would recommend from I've been told erring on the side of caution (and to keep the cost down, too), with your dedicated audio video circuits running to one copper ground rod, with that rod then tied into the house ground.
 

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The grounds have to be bonded together! Look in section 250 of the NEC (National Electrical Code). I feel sorry for anyone who has to pound in 3 groundrods with a hammer. There are easier ways...
 

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Multiple grounds is a bad idea and will not meet the NEC nor most local codes. You are asking for trouble if the room already has an existing circuit that is tied to a different ground than the new circuts being added. If you forget and plug some equipment into the old circuit and attach it to equipment with the new power/ground you can get a current flow. It could be as simple and annoying as a ground loop (Humming, vertical bars, etc) or as lethal as 120 Volts.


I saw one time in an older building on the Aggie campus where there were two electrical systems and two grounds. One rod on each side of the building. The good folks were installing a Cat 3 network (No such thing as Cat 5 back then) and brought up a link between the two subsystems. Later that day the link failed and we went looking. The wire had in fact melted and burned through. Later tests showed over 100 volts on the line. It took some time before they figgured out what was happening along with a dead hub and NIC.


Don't let this happen to you.
 

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Places like Home Depot sell "15" Amp isolated ground hospitol grade duplex recepticals for aprox $20. Go to W.W. Grainger and you will find 20 amp rated IGHGDR's for aprox $30. I presume each of your dedicated circuit breaker circuits is going to be rated for 20 amps, so you should get the 20 amp rated recepticle as well. I started with one and now have three separate circuits, one ground rod for the entire electrical panel, and a brick wall protector for my most senitive items. Randy
 
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