Parallel sets?

[ggunn]

I am looking at some photos from a site assessment for a PV system installation, and it appears that the service conductors are four sets in three conduits. I can't tell for sure, but it looks like they ran two sets in one conduit and two more each in their own conduit. If that's what they did can they still be legit parallel sets?

 

[Dennis Alwon]

As long as they are the same length etc I don't see why that can't be done.

 

[don_resqcapt19]

They do not have the same electrical characteristics where you do not have the same number of sets in each raceway. The impedances will not be the same. I would not be surprised if the AHJ would red tag that installation.

 

[bwat]

It would seem to be a clear no-no to me.

My underline:

310.10(H)(3) Separate Cables or Raceways. Where run in separate
cables or raceways, the cables or raceways with conductors shall
have the same number of conductors and shall have the same
electrical characteristics. Conductors of one phase, polarity,
neutral, grounded circuit conductor, or equipment grounding
conductor shall not be required to have the same physical characteristics
as those of another phase, polarity, neutral, grounded
circuit conductor, or equipment grounding conductor.

 

[infinity]

I agree also, it cannot be 2 in one conduit and single sets in the others.

 

[Dennis Alwon]

My bad....never thought about the impedance.

 

[Hv&Lv]

I am looking at some photos from a site assessment for a PV system installation, and it appears that the service conductors are four sets in three conduits. I can't tell for sure, but it looks like they ran two sets in one conduit and two more each in their own conduit. If that's what they did can they still be legit parallel sets?

Seems like they assumed from the start three sets and later in the job there was an “uh oh” moment…

“just see if we can get by with this, maybe no one will notice”

 

[ggunn]

They do not have the same electrical characteristics where you do not have the same number of sets in each raceway. The impedances will not be the same. I would not be surprised if the AHJ would red tag that installation.

That's what I figured; also their ampacities would not be the same because of conduit fill derating of the doubled up set. It's a pretty old existing service. I want to be careful; I don't want to get hung with "you touch it you fix it"; it's an underground run of about 100'.