Sharing ground wire between two dedicated circuits

As long as both circuits originate from the same panel you can share the ground -- if your jurisdiction uses NEC 2014 or later.

Note that 10/3 Romex has three uninsulated wires (black, white, red) and a bare ground, 4 wires total. The insulated red wire you are making a ground must be wrapped with green electrical tape where visible (in the outlet box, panel or any intermediary junction box).

If you are using metal boxes, you can use the bare ground clipped/screwed to the 10/3 box and the insulated (taped green) conductor on the 10/3 receptacle ground screw. You can then tie the 10/2 ground from the 10/2 receptacle (or metal box ) to the 10/3 box.

If plastic boxes, then run the #10 insulated "ground" from receptacle screw to screw and clip the bare grounds back to the orange insulation.

gs5556, amazing answer thank you

Is Romex 10/3 good for the dedicated Circuit?  I was told the ground was insulated, which seems like a good idea. True?

I was also told 10/3 better to use vs 10/2, because the ground is insulated and 10/2 is not. So it's all a bit confusing

@emergingsoul If you’re going to spend this kind of money for two dedicated circuits, why not just spend a tiny bit more for the best? If they are truly dedicated circuits, with dedicated circuit breakers, their grounds should both never intercept with each other, until they reach the circuit breaker box (aka load center). Instead of using Romex, go a step further, and use Aluminum Armor Clad for Healthcare Facilities (AC-HCF). It’s the absolute best choice for Isolated Ground A/V systems. The biggest benefit is that the average proximity of the hot conductor and the neutral conductor, with respect to the isolated equipment grounding conductor, is nearly equal, virtually eliminating ground voltage induction (GVI), even on long runs. If you go that (AC-HCF) route, I’d also use isolated ground outlets.

@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.

.