Google is wonky on that one! The ground provides a safe, low impedance path for any fault current to return to earth or the transformer.Google says, “the ground provides a path for Excess electricity to escape.” Where does excess electricity come from? I guess if the neutral was broken or open then the hot would have no where to go but how does it get to the ground?
It seems to me that with a GFCI, a ground is not necessary and code agrees.
But anyway, I’ve got grounds now.
I'll try to explain below. Please pardon so many words!
Fault Current Example:
Suppose that I have a motor in my air handler and the insulation on the wiring leading to the rotor windings deteriorates from age. The wire is certainly in contact with the motor frame at some point or another. When the insulation breaks down, the electrons in the wire can travel through the motor's case. The case is attached to the air handler frame. The frame to the duct work,, etc.
If the equipment is not grounded and one touches the air handler or the duct work and that person touches something else that is grounded, that person will conduct the current from the motor to earth.
If the equipment is grounded, the fault current will rush to earth. This will cause excess electrons to flow to the motor and the fuse will open or the breaker will trip.
Another example is laying on the pavement under a car with a 120-volt drill with a 3-wire cord cap. If the drill isn't properly grounded (or otherwise protected) and develops a fault, the fault current will pass through the user.
The worst cases are if the accidentally energized item is touched with the left hand and the left foot or right hand touch something grounded, the current passes through the heart. The other worst case is if one touches the energized part and the person's head touches something grounded.
For requiring neutrals in all boxes (with a few exceptions), the reason for the code change was because many new dimmers, occupancy sensor switches and similar now require a neutral. People cheated and used the equipment grounding conductor for a neutral. Now, the unbalance (neutral current) of 120 volts travels down the uninsulated ground wire. This can be a fire hazard. But more importantly- if someone touches something grounded, such as a refrigerator, and then touches something that is grounded better than the ground wire for the refrigerator (faucet, for example), that person will carry that neutral current from the dimmer switch that uses the ground wire for a neutral. (That's similar to why it is against NFPA 70 to use the grounding conductor on a clothes dryer or range or cook top that needs a neutral for a timer, light, etc.)
Possibility:
The above comments may open a Pandora's box of people disputing what I wrote & calling me unqualified or uneducated. (It happened on the crabby people DIY forum recently for a similar grounding topic.)
Since I'm not the best explainer of things, I'll be very happy to explain better, but I won't defend my position.
PS: I'm a master electrician licensed in 7 states & 2 provinces. I am a former inspector. I am an impartial witness for insurance tort cases and arbitration hearings. And I've more qualifications too boring to mention. I kinda sorta know what I'm talking about.
Paul
PS: Your wiring looks great Ron!