Conduit fill and Jumper for multiple conductors - NEC code

[inforaj]

NEC code says that the conduit fill should be 31-40% for multiple cables. That will apply to all kinds of cable/jumpers?

These kinds of installations were found during today's site visit. The installation contractor was saying this jumper was installed per the NEC code.
This is the pathway crossing conduit from one string to another.




Thanks in Advanced.

 

[augie47]

FYI "Nipples" not exceeding 24" can have 60% fill

 

[infinity]

I'm not a PV guy but that looks like a sleeve.

 

[Dennis Alwon]

I'm not a PV guy but that looks like a sleeve.

I agree. It isn't a complete raceway so not an issue.

 

[pv_n00b]

This occasionally comes up when someone wants to use some type of sun protection cover for the conductors but it's not considered conduit. How many conductors can they put In there? There is no solid answer I know of.

 

[jaggedben]

I agree. It isn't a complete raceway so not an issue.

Really? What's the difference?

 

[jaggedben]

I think what bothers me most in the pic is no straps holding the conduit to the blocks.

 

[wwhitney]

Really? What's the difference?

Suppose your piece of conduit, instead of being conduit, was plumbing pipe, so the NEC doesn't recognize it as conduit. Would that create an NEC violation? If not, then the fact that you chose to use conduit to accomplish whatever it is accomplishing doesn't matter. And so that piece of conduit is not subject to the various restrictions imposed on conduit systems.

Cheers, Wayne

 

[RWC/NC.]

I'm also having somewhat limited experience w/Chapter 7 Article 705. But I'm seeing this as "raceway" in the picture provided. Quoting Article705.25 (A) General. Wiring Methods. *Hypothetical Question: Would you consider 8' or 10' section galvanized ridged conduit (GRC) between two cable trays (w/bonding bushings) a protective sleeve or complete raceway (?)

 

[ggunn]

I agree. It isn't a complete raceway so not an issue.

What makes a raceway "complete"? I don't see anything that would exempt it from conduit fill rules.

 

[pv_n00b]

Suppose your piece of conduit, instead of being conduit, was plumbing pipe, so the NEC doesn't recognize it as conduit. Would that create an NEC violation? If not, then the fact that you chose to use conduit to accomplish whatever it is accomplishing doesn't matter. And so that piece of conduit is not subject to the various restrictions imposed on conduit systems.

Cheers, Wayne

Ah yes, this is the crux of the issue. If the conductor would not require conduit to be an NEC-compliant installation and I put it through some type of sleeve of some kind because I feel like it that day, do I have to treat that sleeve as conduit even though it's not used as a conduit to comply with anything?

 

[Dennis Alwon]

What makes a raceway "complete"? I don't see anything that would exempt it from conduit fill rules.

A raceway is complete when the raceway goes from one location directly to another without a break in it. If not then thios section would not make sense

300.18 Raceway Installations.
(A) Complete Runs. Raceways, other than busways or exposed
raceways having hinged or removable covers, shall be installed
complete between outlet, junction, or splicing points prior to
the installation of conductors. Where required to facilitate the
installation of utilization equipment, the raceway shall be
permitted to be initially installed without a terminating connection
at the equipment. Prewired raceway assemblies shall be
permitted only where specifically permitted in this Code for the
applicable wiring method.
Exception: Short sections of raceways used to contain conductors or
cable assemblies for protection from physical damage shall not be
required to be installed complete between outlet, junction, or splicing
points.

 

[wwhitney]

Ah yes, this is the crux of the issue. If the conductor would not require conduit to be an NEC-compliant installation and I put it through some type of sleeve of some kind because I feel like it that day, do I have to treat that sleeve as conduit even though it's not used as a conduit to comply with anything?

Obviously not. Just write "NOT CONDUIT" on it. : - )

Seriously though, being conduit means that if the installation complies with certain restrictions (that it's listed conduit and that it meets the various restrictions placed on that type of conduit), you get certain resulting allowances (such as being able to run individual conductors through it as a wiring method). If you don't require those allowances, then you don't need to satisfy all the restrictions.

Cheers, Wayne

 

[jaggedben]

A raceway is complete when the raceway goes from one location directly to another without a break in it. If not then thios section would not make sense

Ok, so per your quote, it is clearly a raceway in the photo, whether or not it is complete. And in the case in the photo, the exception also clearly applies, so no violation of your quoted section in the photo. Two questions then...

1) what section of the code exempts such short, incomplete raceways from fill requirements?

2) It is common in the PV industry to run incomplete raceways (like the one in the photo) for much longer distances. But PV arrays do not contain any outlets, or any enclosed junction or splicing points for such conductors (typically). (690.31(C) 1 permits them to be run as single conductors "within the array".) So is a longer, incomplete raceway a violation? (I don't think so.) Supposing it's not, why should it be exempt from fill or derating requirements?

 

[wwhitney]

1) If it has to be a raceway, then there is no exception, just the allowance of 60% for 24" or shorter nipples.

2) So an array is "A mechanically integrated assembly of module(s) or panel(s) with a support structure and foundation, tracker, and other components, as required, to form a dc or ac power producing unit." That means the photo in the OP shows 2 arrays, and the conductors shown are not "within the array"?

That would mean the raceway shown has to be a raceway, and so the fill limits would apply. I also wonder a bit about the transitions at the end of the conduit, whether there is any code section that would require a box or a clamp.

Cheers, Wayne

 

[Dennis Alwon]

1) If it has to be a raceway, then there is no exception, just the allowance of 60% for 24" or shorter nipples.

2) So an array is "A mechanically integrated assembly of module(s) or panel(s) with a support structure and foundation, tracker, and other components, as required, to form a dc or ac power producing unit." That means the photo in the OP shows 2 arrays, and the conductors shown are not "within the array"?

That would mean the raceway shown has to be a raceway, and so the fill limits would apply. I also wonder a bit about the transitions at the end of the conduit, whether there is any code section that would require a box or a clamp.

Cheers, Wayne

I respectfully disagree. I see the conduit as a sleeve and not a raceway. If that isn't a sleeve then what constitutes a sleeve

 

[wwhitney]

I respectfully disagree. I see the conduit as a sleeve and not a raceway. If that isn't a sleeve then what constitutes a sleeve

I think the question comes down to the wire type that is running through that piece of metal tube. If it's a wire type that can be run exposed without relying on the 690.31(C) allowances, then I agree with you it's a sleeve. If it's a wire type that is normally required to be run in a raceway, but 690.31(C) allows an exception to that ("within the PV array"), then whenever 690.31(C) doesn't apply, you need a raceway, and so the metal tube in the picture is the required raceway.

Cheers, Wayne

 

[Barbqranch]

I wonder why you even need to run that many wires between the two arrays. It seems like adding excess wire length (resistance) to the system, plus more connectors to potentially give trouble.

 

[jaggedben]

I respectfully disagree. I see the conduit as a sleeve and not a raceway. If that isn't a sleeve then what constitutes a sleeve

Good question. Is 'sleeve' an enforceable code term or just a colloquialism?

 

[jaggedben]

...

2) So an array is "A mechanically integrated assembly of module(s) or panel(s) with a support structure and foundation, tracker, and other components, as required, to form a dc or ac power producing unit." That means the photo in the OP shows 2 arrays, and the conductors shown are not "within the array"?
...

Whatever you call it, the pipe in the photo definitely isn't mechanically integrated to the array (or anything else!) and thus the conductors aren't within the array. If the pipe were mechanically attached to the racking on both ends the discussion could be different.