Paul Bates
Member
I recently inspected a 800 amp main breaker (500 mcm thhn) 120/208 volt electrical service where the electrician used a 1/0 cu conductor to the water pipe for the grounding electrode. I instructed him to remove the 1/0 cu and install a 2/0 cu grounding electrode conductor per table 250.66, instead he installed an additional #4 cu grounding conductor in parallel with the 1/0 cu and contends it is the same circular mill as a 2/0 cu and therefore is OK. I contend it violates 310.4 for parallel conductors and cannot be used for grounding. Comment Please?
