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

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.

@carlsbad

What type of wiring method did you use?

Did you install a 3 wire 120/240V multi wire branch circuit consisting of two Hot conductors, one common shared neutral conductor, and one EGC (Equipment Grounding Conductor)?

If yes, only the unbalanced load current of (L1) to neutral and (L2) to neutral will return on the neutral conductor back to the source. The balanced load of (L1) to neutral and (L2) to neutral are in series with one another and are fed by 240V, nominal.

Here is a good example of how a 3 wire multi wire circuit works.

(Imagine the transformer’s split phase secondary winding is 120/240V)

@jea48 are you suggesting that the common neutral allows noise from one leg to affect the other leg?  I considered that and rejected it thinking the large and lightly loaded neutral would kill the noice.  Now I'm questioning that conclusion.

Jerry

@carlsbad said:

are you suggesting that the common neutral allows noise from one leg to affect the other leg?

No I am not suggesting that at all. What I am saying is the balanced load(s) "noise" on one leg is in series with the other leg and is fed by 240V.

Example: Say you have a total of 2 amps on (L1) leg and 4 amps on (L2) leg. That means only 2 amps, (the unbalanced load), will return to the source on the common neutral conductor of the multi wire 3 wire branch circuit. The other 2 amps, (the balanced load), of each leg is in series with one another and is fed by 240V. So say in the "other leg" there are devices that create "noise" that goes back out on the mains. Say this leg has the total of 2 amps. None of this "noisy" combined loads will will return on the common neutral conductor to the source. All of the 2 amp load will be in series with the AC line side of all the audio equipment on (L2) leg and return to the source.

The Circuit:

Hot (L1) leg conductor connected to >> (2 amp "noisy" loads) connected to, >> common neutral connection joint connected to >> ( 2 amp balanced load of the 4 amp total load(s) on (L2) leg), connected to the Hot (L2) leg conductor back to the source .

Worth noting both the Hot and Neutral conductors are current carrying conductors when a load is connected to both of them. In a normal 2 wire circuit the current in both conductors will be the same.

I hope you took the time and watched the video in my last post.

This also may help.

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