MV bare grounding cable

[faresos]

I'm working on a project that we are using a MV system (4,160V) to power 350HP pump station. The reviewer has indicated that we need to add a bare grounding conductor for the primary cables. Why bare conductor and not insulated? Is the bare conductors needs to be ran inside the conduits with primary cables? How we size the bare grounding conductors if we are using #4/0 for primary cables?

Thanks in advance for your thoughts.

 

[don_resqcapt19]

Is the raceway nonmetallic? I have often seen bare EGCs specified for use with nonmetallic raceways. I think that the idea is that there is a better chance for any fault current to get on the EGC if it is bare. As far as sizing, it is an EGC and you use T250.122.

 

[faresos]

Is the raceway nonmetallic? I have often seen bare EGCs specified for use with nonmetallic raceways. I think that the idea is that there is a better chance for any fault current to get on the EGC if it is bare. As far as sizing, it is an EGC and you use T250.122.

Thanks Don for your response! yes we are using PVC conduit for this run. I just wasn't sure why the use of bare conductor in lieu of insulated sire, but what you have said makes sense. Thanks again!