biggladant
Member
- Location
- Kansas
I am parelling 3 sets of 350's 3-phase no nuetral so 3-350's per phase and 1/0 ground I have a Utility supplied Transformer, from there 3 conduits with set of 350's in each one to a main breaker enclosure with 800 amp breaker, from there 3 more conduits with a set of 350's each to a motor starter panel. I have a ground rod at all three locations. From the breaker to my motor starter panel I sized my equipment grounding conductor from table 250.122, 1/0 for 800 amps. My ground rods I believe can be #6 copper although I am also useing 1/0. If I am right so far my question is first- what to call my grounds from the transformer to the breaker enclosure? I believe they are the grounded conductor brought to service equipment. Second how to size this? If I read 250.66 it has a FPN under the first paragraph that leads me to 250.24B for grounded conductor brought to service equipment. If I read 250.24B2 since I am useing 3 different raceways I sized my grounded conductor off of 1 350mcm then to 250.66 which would only require #2 but cant go smaller than 1/0# becuase of 250.24B2.
Am I doing this right as a 1/0 seems small to me especially after looking at an identical sevice where 3/0 was used as grounded/grounding/GEC.
Am I doing this right as a 1/0 seems small to me especially after looking at an identical sevice where 3/0 was used as grounded/grounding/GEC.
