Good questions Dr. shows some people actually think about all this stuff and actually it can save your life or prevent a fire ya know!! You asked for EE's, well that's me HOWEVER I been long retired and rusty as an old nail and NOT familiar with the latest codes so NO WARRANTY.
Besides, Billy Bob and Bubba who wired their garage over a case of beer can NOT be kept away lol as all are entitled to their opinions be they right or wrong, lay or professional, and they love electrical and legal questions best ya know. The more the merrier, bless all here who try to help, but just consider the source if youre making an important or life critical decision!!
"Now, here"s my question(s) - Knowing that the Insulated Green & the Bare Copper are BOTH Grounds, are they two SEPARATE animals having the SAME FUNCTION , or are they entirely different."
In say a 3 wire 120 volt branch circuit you have the UngrounDED Conductor (Hot),,,,,The Grounded Conductor (Neutral),,,,,,,,and an Equipment GroundING Safety Conductor......Okay the EGC can be EITHER insulated Green (like used inside conduit) orrrrrrrrrrrr it can be bare copper (like in Romex) BOTH SERVE THE SAME PURPOSE AND EITHER WORKS. Its purpose is to provide a dedicated current return ONLY for fault current. Its NEVER to carry normal return current, that's the job of the Neutral Grounded Conductor which is insulated. I bet you wouldn't remove the insulation and touch it standing barefooted on concrete would ya??? cuz if so you risk placing your body in a parallel current path with a live conductor YIKES....... However, the Equipment GroundING Conductor is often tied to the outer metallic conductive cases of tools or appliances and you do touch them. Another reason to NOT switch or mix n match Neutrals and Grounds!!!
"Can they be BONDED TOGETHER and used as both Equipment Ground AND Stray/Fault Ground - or must Equipment Ground and Stray/Fault Ground be isolated from each other (even though they are both Grounds) ? ? ? !
1) At the main service entrance somewhere,,, YES the Neutral (Whites) anddddddddd Equipment Ground Buss (Greens and bares) anddddddddddd GroundING Electrodes (via No 4 bare copper Grounding Electrode Conductor) are indeed effectively all tied together !!!!!!!!!!!
Dr., sounds like you may be confusing Earth GroundING of the incoming Utility Neutral with Equipment GroundING Conductors??????? The Utility Neutral(s) are earth grounded out on the aerial HV Primary (maybe 9600 volts) as well as the LV Secondary (120/240 volts) as well as at the homes service entrance often at one of three places: Weatherhead riser,,,,,Inside Meter Base,,,,,,Inside service entrance panel. THAT EARTH GROUND OF THE NEUTRAL IS FOR SURGE AND STRAY CURRENTS AND LIGHTNING PROTECTION
AND TO TIE THE SYSTEM AT A COMMON LOW VOLTAGE POTENTIAL IE MOTHER EARTH.
That's NOT the same as the Equipment Safety GroudING Conductors in the home be they green or bare etc.
Often the Neutral is attached to a bare No 4 copper wire knows as the GroundING Electrode Conductor which is attached to a proper GroundING Electrode such as metal water pipes or building structural or foundation steel or "made" electrodes such as copper rods driven into mother earth.
So you have GroundING Electrode Conductors (to earth ground Neutral, often No 4 bare copper wire) and Equipment GroundING Conductors (bare or green insulated which run with 3 wire or more branch circuits for carrying fault current ONLY.
Sooooooo That help,,,,,,,,Can others add to this (EE's and Electricians and Bubbas all welcome)