Wiring 2 outlets to 2 dedicated 20 amp circuits with a single 10/3 electrical wire.

@emergingsoul said:

Yes I know both new circuits or an alternating legs, and that could be a real weakness.

 

But if all the legs where I live are generally quiet then I don’t see the problem on this point.

Got Digital Front End Equipment? The hash it puts back out on the mains ain’t quiet.

Got any SMPS (Switched Mode Power Supply)s? The harmonics they put back out on the mains ain’t quiet.

Using a multiwire branch circuit will dump that crap on the doorstep of the power transformer’s primary winding of the analog equipment. You want noise, that’s a good way to introduce it into your analog equipment.

The other issue, there is a common neutral wire representing a return connection to the panel, but it’s not the incoming voltage wire.

It takes two to tangle.

It takes both lines to feed a 120V potential to a load for current to travel in the circuit. Current travels from the source through the load and returns to the source. The neutral conductor is a current carrying conductor. The same as a hot Line conductor is a current carrying conductor.

Are you saying noise could bleed back to the audio equipment from the neutral?

NO, I am not.

Here is the circuit using a multiwire branch circuit... I hope you can follow it. Draw a one line diagram on a piece piece of paper showing flow of the current through the series circuit.

At the panel you have a Hot L1 bus and a Hot L2 bus.

L1 breaker hot conductor to >>>

digital equipment power transformer primary winding, (OR, SMPS), out to >>>

neutral conductor to junction with shared branch circuit neutral conductor. Neutral conductor from shared neutral junction to >>>

amp primary winding through winding out to >>>

Hot L2 conductor back to the electrical panel breaker on L2.

See it ain’t neutral current carrying the "Noise" created by the digital equipment. It’s the L1 & L2 balanced load current that travels through the AC line side power supply of the digital equipment >>> through the line side power supply of the analog equipment out >>> on L2 back >>> to the electrical panel.

By design the multiwire branch circuit feeds the balanced load current that is fed from Hot L1 conductor >>> (digital equip) >>> in series with >>> (analog equip) >>> Hot L2 back to the electrical panel .

Keep in mind this is a 70 foot run for a romex wire.

Yeah, I got two 10/2 with grd Romex runs 70ft each. Installed them using best practices methods. One dedicated circuit is for digital equipment, the other for analog equipment.

No ground loop hum. No noise. System is dead quiet with ear against speaker grill.

Preamp and power amp are tubes. Dead quiet...

 

I’m trying to keep this conversation understandable because I think people get lost when it’s not dumbed down for non-engineering finance side people

Trust me I’ve tried my best to explain how a multiwire branch circuit works in layman terms. Did you watch the videos I supplied. Did you understand them?

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@jea48Wrote:

Probably the biggest reason for installing more than one Dedicated Branch Circuit is to decouple the power supplies of audio equipment from one another. Example digital source(s) equipment from analog equipment.

I agree!

That was one of the reasons I ran four 60’ runs of galvanized steel armored MC cable 10AWG. That’s four true dedicated branch circuits, one for each mono block amp, one for analog and one for digital. It helps to reduce noise on the AC lines, by reducing the amount of transformers and power supplies on each circuit. Also, the MC helps to reduce hashing noise EMI, and electric fields, on the dedicated branch circuits feeding your audio equipment. You don’t realize how much hashing noise is on the AC lines, until it’s gone. No ground loop hum. No noise. System is dead quiet with ear against speaker horn, I have tube and SS amps. (speaker efficiency is 2.7%). 😎

@emergingsoul Wrote:

Keep in mind this is a 70 foot run for a romex wire.

Will two 70’ runs of 10AWG NM cable aka Romex break the bank?

See below:

Mike

 

You can get 10-4 romex now if you only want to pull one wire or for whatever reason you want to do that , gives you four conductors and a neutral. Still have to share the ground.

Oops , correction 4 conductors total giving you you second neutral.

Jea48

The comments you make are probably clear to some but not me.

Are you saying that the neutral sharing back to the panel is a problem? And if so maybe it's unclear to me why this is.  Not sure I follow the rationale about Power supplies of components sharing in this situation.  Where is the Sharing coming from?

Truth be known, I specifically directed the electrician to create two dedicated lines on the same leg, and then he pulled this crap and I had to live with it.  And having considered what he did, I'm trying to understand whether I should rip it all out and have it redone by someone else. His proposal was unclear but we discussed it and then he comes and starts doing the work and I see one wire coming out of the wall and I ask what the heck is going on. The project didn't go very well. They did manage to install one dedicated circuit elsewhere.  I couldn't get a second dedicated in the elsewhere room because I ran out of room on the panel.