300.3 C Clarification

[noonan]

I have a situation where the previous owner of our site installed a 480V generator feeder (600V insulation) in the same manhole as MV (13.8kV)
feeders. At first, we thought this was a violation, but one of our consulting
engineers indicated it is not.

300.3.C.2.
(e) In manholes, if the conductors of each system are permanently and effectively separated from the conductors of the other systems and securely fastened to racks, insulators, or other approved supports, conductors of different voltage ratings shall be permitted.

My question is, what does "effectively separated" mean. Does it need to be a barrier or can physical space be the separation?

 

[charlie]

My question is, what does "effectively separated" mean?

In most precast manholes, there are brackets installed around the sides for "racking" the cable so they are off the floor and easily accessible. The ducts will normally enter and exit through "windows" (a thin place that is poured without re-bar that can be easily knocked out so a duct bank may pass into the manhole) and the cable racked around the interior. To be effectively separated, the medium voltage cable would be racked on a different level or even on opposite sides of the manhole. :smile:

 

[noonan]

Thanks Charlie.

It looks like they separated as much as they could, but there is one point where they are close. Where they exit the manhole, they are in adjacent conduits. But I suppose that is allowable.