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Joined: Apr 2003
Posts: 15
M
mchimes Offline OP
Member
Hi guys,

Thanks so much for all the replies on my first thread. I decided to refresh this thread with a new question.

Based on your comments, I decided to run 20A dedicated branch circuits to my studio. Keeping computer/peripherals on one circuit and my outboard audio gear on another one. I also decided to run isolated ground circuits.

Question:

Would I benefit from using 10/3 wire over 12/3?

It seems like a heavier gauge wire would result in more consistent supply and lower impedance (but I really don't know why . . . that's why I'm asking you guys!)

The next problem is that if 10/3 would be beneficial, where can I find a 20A breaker that will accept the bigger wire. The Cuttler breakers I saw at HD today were for 14 or 12 gauge.

Any thoughts?

Thanks again,
Mike

Joined: Jun 2001
Posts: 642
N
Member
As a rule the larger the gage of wire the less the resistance/ft. SO while 10-3 will have some benifit the difference will be too small to matter. Also most breakers will accept #10.


ed
Joined: Apr 2003
Posts: 15
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mchimes Offline OP
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Thanks nesparky!

Joined: Jan 2002
Posts: 163
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Member
"I decided to run 20A dedicated branch circuits to my studio... using 10/3 wire"

Wouldn't using 10/3 [or 12/3] to create two circuits create 'shared' circuits, not dedicated circuits?

Wouldn't the sharing of the neutral between circuits undo much of the isolation you are trying to create for this sound system?

Joined: Apr 2002
Posts: 558
C
Member
Dana, If he is running a 10-3 or 12-3 he is technically only running one circuit right? [Linked Image]

Seriously, I do agree with Dana on this. You should not run multi-wire circuits for audio equipment. You should run two 10-2 or 12-2 cables. All current design 15 and 20 amp breakers will accept #10 wire. I hope your planning on getting an electrician to help you with this project. Installing new circuits is not a DIY project.

Curt


Curt Swartz
Joined: Apr 2002
Posts: 558
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I also see no reason to run these circuits with an isolated ground especially if they are originating at the service panel. If you mount your receptacle in a plastic box the only thing your going to be isolating the ground from is the plate screw. In commercial work we use isolated ground receptacles because we are running the branch circuits in metal raceways or with metal cables but since your using type NM cable your ground is already isolated.

Curt


Curt Swartz
Joined: Apr 2003
Posts: 15
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mchimes Offline OP
Member
To clarify . . . each receptacle will have it's own circuit. I was just trying to find out whether to use 10/3 or 12/3.

Caselec . . . if all anyone needed to achieve an "isolated" ground was just a dedicated circuit and a receptacle, then why do people even bother w/ a true Isolated Ground receptacle. I've been following a Black & Decker book for home wiring that suggests IG circuits for computers and sensative electronic equipment . . . it says IG circuits "provide extra protection against power surges that can hram equipment." Also, every studio I've been in has them.

So are you saying that connecting the bare wire of 12/2 cable to the grounding screw of a receptacle mounted in a plastic box offers precisely the same protection a 10/3 IG circuit?

They would perform precisely the same?

As far as hiring an electrician, I may hire one . . . I spent $300 a year ago having an electrician install 3 dedicated circuits in my other house for my audio. It seemed like alot of money, but I wanted it "done right." About a week later I flipped on a light switch and noticed a pop in my speakers (which were powered by one of his dedicated circuits). So I spent all that money for good expertise to achieve isolation and I didn't end up getting any. So that is one of the reasons I am on this forum . . . to learn how to do it right. And there seems to be more than one way to do it.

After reading the B & D book, installing a new breaker and pulling cable for a circuit seems to be within the capability of a prudent home owner (at least the book says so).

If I do the work myself, rest assured it will be thoroughly researched . . . I won't do anything I don't think is within my abilities.

Thanks,
Mike

Joined: Nov 2002
Posts: 267
W
Member
I have recently completed a recording studio in my basement. We have digital equipment recording equipment that's well internally grounded and balanced input and output jacks to prevent static and noise. We went over which would be the best and safeset way to power all the equipment. We ran dedicated 20 amp ckts using normal 12/2 romex. Bought a power conditioner for spikes and noise. Everything is running clean. The niose and hum we experienced is looping through solid state amps which have preset gains and overdrives. That is just a matter of readjustments. All of our input extensions are run in sheilded cable. Learning to run all this digital equpment is definately a challange but that's another story.

~Ange

Joined: Apr 2003
Posts: 15
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mchimes Offline OP
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Thanks Wirenutt . . . my studio is digital too so I will take note of your suggestions.

Thanks,
mike

Joined: Nov 2000
Posts: 2,148
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Member
Quote
it says IG circuits "provide extra protection against power surges that can hram equipment."
How does this work. The only difference between the IG and a standard circuit is the loction of the EGC termination. In a building with only one panel, even that is not different. There is no way that an IG circuit has any effect on "power surges". It may be able to reduce some of the "noise" on the EGC, but that is all it can do.
Don

[This message has been edited by resqcapt19 (edited 05-06-2003).]


Don(resqcapt19)
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