Dan i do not know how far you are from rob but lambcrusher did some work for him.
i would try to get an electrician that had nothing to do with the install to look at it, i would look into friends that might be electricians first if you have none i would see about getting LC down there to look at it, look no mater how you look at it one 6' ground rod for (i am guessing here) 400amp service is not good. and a question, you might have posted pics of your shop, but is it a steel or metal structure.
i would try to get an electrician that had nothing to do with the install to look at it, i would look into friends that might be electricians first if you have none i would see about getting LC down there to look at it, look no mater how you look at it one 6' ground rod for (i am guessing here) 400amp service is not good. and a question, you might have posted pics of your shop, but is it a steel or metal structure.