Sharing ground wire between two dedicated circuits

@emergingsoul said:

Idea has been proposed to share the insulated ground from the 10/3 wire with the other 10/2 dedicated circuit. Achieves the same thing at a lot less cost? Does this make sense?

No not to me it doesn’t. Per NEC the EGC, "(Equipment Grounding Conductor), shall be installed in the same raceway, or cable, as the branch circuit conductors.

You are planing on using the EGC of the 10/3 NM cable, (Romex is a trade name), for the EGC in the 10/2 NM cable.

Just curious what’s your reasoning or importance for the EGC being insulated in a PVC jacketed cable. The EGC has one purpose. To carry ground fault current back to the source.

You didn’t say what type of outlets you are going to use. IF you are planing on using IG, (Isolated Ground), outlets they would not serve any purpose whats so ever connected to MN cable. None...

I assume you will be hiring an electrician to do the wiring project. A reputable Licensed Electrician will not do what you want to do with the green taped insulated EGC from the 10/3 NM cable.

Just use 10/2 NM for both branch circuits or better use 10/2 solid aluminum armored MC cable. The EGC is insulated green in color. The three conductors are tightly twisted spiral its entire length. Very tightly twisted...

Example Aluminum Armored 10/2 MC cable. (Tell the Electrician yo want solid core conductors only...)

Southwire Armorlite 250-ft 10 / 2 Solid Aluminum Mc Cable

You can also use plastic boxes for the outlets instead of steel boxes if you want. It meets NEC code. With that said the AHJ, (Authority Having Jurisdiction), has the final say. Your electrician will know...

/ / / / /

Integrating Electronic Equipment and Power into Rack ...

Go to page 12 and page 13

Two conductor plus 1 ground MC (Metal Clad) is a good choice for Non-Isolated Ground A/V systems. MC cable contains a safety
grounding conductor (wire). The three conductors in the MC cable (Line, Neutral and Ground) are uniformly twisted, reducing both
induced voltages on the ground wire and radiated AC magnetic fields. The NEC article 250.118 (10)a prohibits the use of this cable for
isolated ground circuits because the metal jacket is not considered a grounding conductor, and it is not rated for fault current.

.

Here you go.  This is the best treatise on wiring for AV/2-channel audio that I have seen.  Basically, it is the wiring scheme I have used for years.  This works.

I would never waste any money on Romex. An connecting grounds any where besides earth creates a ground loop.

Ground Connects to a stake in the dirt, why don't you like romex?