Why is it necessary to have gear on the same phase from electrical panel?

Correction.

I worked with a member that has a single phase 240V to 120V 15KVA outdoor Pad Mount transformer that feeds a 120V only sub panel for his dedicated audio room.)

That should read:

I worked with a member that has a single phase 240V to 120V 15KVA outdoor Pad Mount transformer that feeds a 120V only panel for his dedicated audio room.)

It is not a sub panel.

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Jea48

This is a really awesome explanation thank you very much.

I guess a Cable connected between two components that happen to be plugged into different circuits effectively creates a bridge of power between the two phases, although add to a very low Energy level.  The components are likely designed in such a way to avoid impact due to this bridge.  
 

Existence of the bridge nevertheless is a source of interference because there is some communication between the two components of electricity flow which causes noise?  
 

Even if you use the same Circuit for connecting components and mixing outlets you still run the risk of creating hUms because use of different outlets causes ground loop issues because grounding is now shared between two outlets which is not healthy and creates an antenna along the grounding path. Does all this make sense?

This is my issue with both plugs in an audio room having to be on the same hot wire. One side is grounded anyways &neutral) Hotside is grounded thru an average of 10 ohms with other items connected in the house and your audio gear anyways. A fe volts difference in an unbalanced load across both ht wires amunts to about zero infle

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

One side the neutral is connected to ground not matter what circuit hot side you are using. The hot is actually grounded too thru about 10 ohms load with other items in the house drawing current besides your audio gear and lower with AC running. What's the difference in noise with both circuits on one side or split by both hots?

 

 

 

 

I am sorry the post I was typing above decided on its own to post before I was finished. This site is finicky.

Ok.  I actually understand electricity.  And I can't think of a reason.  

Ground IS important.  You can have a ground loop so how you ground can be important.  but which hot leg you use isn't important.

I ran two circuits to my system, one on each leg.  I do keep my system all on the same leg and plug other things into the other leg but that is really just a local thing.  Once it goes back to the panel, all bets are off.

Jerry