You can change the wall outlet to a 4 prong receptacle. 2 120 volt wires, 1 neutral wire, and one ground wire. Drive a copper clad ground wire into the ground and attach a #10 wire from the receptacle to the ground rod.
I have a 200 amp service disconnect behind the meter socket and then it goes into my main panel in the cellar. By code I had to separate the grounds and neutrals, and run a copper ground wire from the panel out to the well casing. When the service was originally installed there was a requirement for a ground rod in the cellar that bonded to the neutral and the ground wires in the panel. When I was required to separate the grounds and neutrals, I was told that I should "hit" every ground rod that was previously used and keep going until I finally made it to the steel well casing and it should be bonded to the casing. The way that it was originally laid out, I had 3 ground rods, and when the meter was moved, I installed a 4th under the meter socket. That copper wire is one continuous wire through the clamps on all 4 ground rods, and it is bonded to the well casing. The Utility (CL&P) installed a ground rod at the base of the pole where the transformer is located bringing the total number of ground rods to 5.
The ground rods are to capture any failure of the neutral wires in the system.
Edit: I misread the original post, but after reading it a second time, I believe that you are going to be back feeding the electrical pane with the generator through a 3 prong receptacle. Is this correct? Are you installing a service disconnect on the service panel or are you going to be turning off the main circuit breaker when using the generator?
You have answered my question!
Thank you!
My arrangement likely will be described in somewhat nasty terms by others here on OTT.
I will be tripping the main and back feeding.
I have done this MANY times prior.
I use a checklist!
No other person will have access to the generator.
I have lived my life with checklists!
I have 30,000+ hours of flight time.......ALL with the use of checklists!
Some of my early flight experience included using checklists to land safely aboard an aircraft carrier.
At 83+, I am still alive,.......thanks to my using, and understanding, the importance of checklists!
I am presently thinking that I shall replace the 3 prong receptacle with a 4 prong, and run a #10 bare ground from that ground terminal to a copper clad ground rod.