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Question on dedicated circuits-isolated grounding
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Author:  Armando [ Sat Aug 25, 2018 9:41 pm ]
Post subject:  Question on dedicated circuits-isolated grounding

Hello! When my home was being constructed, I requested to have the electrical supply to the room being dedicated as my studio space be separate from the supply to the rest of the home including lighting. What the electrician did was dedicate a 60 amp breaker in the main box to the studio. He then installed a separate circuit breaker box with its own 20 & 15 amp breakers supplying all electrical outlets in the room.

My question is: is this configuration considered “isolated ground circuits”? Because the individual circuits in the room outlets are all branched from the 60 amp breaker in the main box does this mean the ground is contaminated with the entire home?

Thanks in advance!

Author:  Speedskater [ Sat Aug 25, 2018 11:00 pm ]
Post subject:  Re: Question on dedicated circuits-isolated grounding

Does the studio wiring use:
a] metal conduit (ridge or flexible)?
b] plastic conduit?
c] NM (Non Metallic) cable (i.e. Romex®)?
is it a 240V 120/120V box or just 120V?
* * * * * * * * * * * *
I would prefer to have one feeder for the audio system and another feeder for lighting, HVAC and appliances.

* * * * * * * * * * *
in any case, if you put the audio equipment on one 120V pole or leg and everything else on the other, you should be OK.

Author:  Armando [ Mon Aug 27, 2018 11:21 pm ]
Post subject:  Re: Question on dedicated circuits-isolated grounding

Speedskater wrote:
Does the studio wiring use:
a] metal conduit (ridge or flexible)?
b] plastic conduit?
c] NM (Non Metallic) cable (i.e. Romex®)?
is it a 240V 120/120V box or just 120V?
* * * * * * * * * * * *
I would prefer to have one feeder for the audio system and another feeder for lighting, HVAC and appliances.

* * * * * * * * * * *
in any case, if you put the audio equipment on one 120V pole or leg and everything else on the other, you should be OK.


It’s 20A romex. The breaker box in the studio contains several 20 and 15 amp breakers which are fed from the 60A breaker off the main box located in the garage. Lights,HVAC, etc are not fed from either the 60A breaker or the individual breakers in studio.

Can additional steps be taken to keep electrical free of line noise? Thanks!!

Author:  Speedskater [ Mon Aug 27, 2018 11:49 pm ]
Post subject:  Re: Question on dedicated circuits-isolated grounding

Romex® [ NM (Non Metallic) cable ] almost never needs (or gains anything) from Isolated Ground receptacles. The only exception might be a building with metal wall framing. And then Romex® doesn't have the needed two Safety Ground wires.

If only the audio equipment uses the 60A feeder as the path back to the main breaker box, then NO the Safety Ground is not contaminated.

Author:  Armando [ Mon Aug 27, 2018 11:53 pm ]
Post subject:  Re: Question on dedicated circuits-isolated grounding

Ok thanks for that info!

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