1-For grounding rod system calculation you can refer to IEEE 80 or BS 7430. 2-Interconnection or isolation of various grounding system such as electrical and instrumenta or electronic grounding system is subjected to standards or technical code discaussions. There are some advantage and disadvantages for each grounding way. For example, according to IEEE 142, since the power grounding system had been found to cause malfunctions and failures of electronic equipment, a logical solution was to not use the building