Time for dedicated outlets!

@cerberus79,

Run a 12/3 romex that is a neutral with two lines and a ground. This will give you two dedicated 20 amp cicuits with one run.

No, that would be 2 separate 120V circuits. A 3 wire 120/240V multiwire branch circuit. Two separate 120V circuits with a shared/common neutral conductor.

A 120V dedicated branch circuit is a branch circuit with a dedicated,
Hot conductor
Neutral conductor
Equipment grounding conductor.

A true dedicated circuit does not share a raceway, conduct, or cable assembly, with any other circuits.

Multiwire branch circuits are not recommended for feeding audio equipment. Especially where audio equipment is connected together by signal wire interconnects.

It also should be mentioned the 2 circuits of the 120/240V 3 wire multiwire branch circuit must be connected to a 2 pole breaker, per NEC.

Only the imbalanced load, of a 3 wire multiwire branch circuit will return on the shared neutral conductor back to the source, the electrical panel. The balanced load of the 3 wire circuit is in series with the two hot ungrounded conductors.
Example: If the connected load on L1 to neutral is 5 amps and the connected load on L2 to neutral is 5 amps, zero amps will return on the neutral conductor of the branch circuit back to the source. The two loads are in series with one another, essentially being fed by 240V.

So say Digital equipment is fed from one of the separate 120V circuit outlets and the analog is fed from the other separate 120V circuit outlet, Only the imbalanced load of the digital equipment and analog equipment will return on the neutral conductor. The balanced 120V loads, of the two connected loads, will be in series with one another. Do you really want the digital hash going back out on the power cord/s of the digital equipment coupled to the power transformer/s of the analog equipment?
Here is a very good video on how a multiwire branch circuit works.
https://www.youtube.com/watch?v=eVamt9IdQd8
.

Jea48, The NEC does not clearly define that and it is left as a design perrogative. It is understood that a dedicated circuit is one where only one appliance will use that circuit. A neutral can be shared but only one appliance per breaker. Some elect to run a neutral for each as a design choice. In either case the neutral is run back to the panel and attached to the neutral bar where all the other neutrals are.

Also you would not connect to a double pole breaker, that is for 240 vac here in the US . They would connect to single pole breakers as they are 120 vac. 

Why eould you not use the bare wire for ground ? That is its intended purpose. In romex each circuit wire has insulation and the ground is bare and all of it is in a protective sleave

cerberus79      17 posts                                        05-06-2017 9:09pm

Also you would not connect to a double pole breaker, that is for 240 vac here in the US . They would connect to single pole breakers as they are 120 vac.

Multiwire branch circuits

A multiwire branch circuit basically consists of two or more ungrounded conductors that share a neutral. All conductors of a multiwire branch circuit must originate from the same panelboard [210.4(A)].

For personnel safety, each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at its origin [210.4(B)]. If that origin is two or more breakers, you can provide this disconnect by using single-pole circuit breakers with handle ties identified for the purpose [240.15(B)(1)].

http://ecmweb.com/code-basics/branch-circuits-part-1

"single-pole circuit breakers with handle ties identified for the purpose"
The tie used must be a Listed tie for the intended purpose.
Or, just use a 2 pole breaker......
Or, in the case of a 3ph. 4wire multiwire branch circuit a 3 pole breaker.

Just going from memory I believe this was added to the 2008 NEC. After State and local AHJs adopted the new language, at least in my state, the 120V as well as 277V multiwire branch circuit became a thing of the past. I don’t know of anyone that installs them today, or for the last 8 years.

Best regards,
Jim