PV Source Circuit Conductors run in non-UL listed raceway.

[Anode]

Looking at a BIPV project, where pv source circuit conductors are being proposed as running inside a custom aluminum extrusion going east to west, this portion is left open and accessible, and should be of no concern.

Where I am curious, and expressing concern, is where those conductors enter an also custom aluminum extrusion that essentially runs up a rafter, and that raceway is then closed of by a removable piece that is screwed in.

There is no concern of damage to the conductors where the secondary piece screws to the aluminum mullion, as the design of the extrusion makes it impossible.

Without you seeing the design of the extrusion, can you think of any issues we may face with respect to being not compliant with NEC code? Thanks in advance.

 

[iwire]

You cannot use unlisted raceway for individual conductors. Only cables.

 

[Anode]

You cannot use unlisted raceway for individual conductors. Only cables.

Thanks for the response.

Can you explain the difference? And you provide some reference to the NEC?

 

[Carultch]

Thanks for the response.

Can you explain the difference? And you provide some reference to the NEC?

A cable is an assembly of multiple conductors, that would have an outer jacket or cladding. Do a search on SER and MC cable to see examples.

 

[Carultch]

Looking at a BIPV project, where pv source circuit conductors are being proposed as running inside a custom aluminum extrusion going east to west, this portion is left open and accessible, and should be of no concern.

Where I am curious, and expressing concern, is where those conductors enter an also custom aluminum extrusion that essentially runs up a rafter, and that raceway is then closed of by a removable piece that is screwed in.

There is no concern of damage to the conductors where the secondary piece screws to the aluminum mullion, as the design of the extrusion makes it impossible.

Without you seeing the design of the extrusion, can you think of any issues we may face with respect to being not compliant with NEC code? Thanks in advance.

If the wires don't require a raceway to begin with, it is very common that you end up using a structure for support that isn't a standard raceway. Such as securing the cable in open air along a racking structure. But in order to be able to do that, you first need a kind of wire that doesn't require a raceway in this application. Such as listed PV wire.

 

[Anode]

If the wires don't require a raceway to begin with, it is very common that you end up using a structure for support that isn't a standard raceway. Such as securing the cable in open air along a racking structure. But in order to be able to do that, you first need a kind of wire that doesn't require a raceway in this application. Such as listed PV wire.

Makes sense. As we do this on 100% of our standard installations.

The conductors are all PV wire coming back from the sub arrays. So does that mean in your opinion these would be permissible to run along the aluminum extrusion up the rafter?

 

[iwire]

Makes sense. As we do this on 100% of our standard installations.

The conductors are all PV wire coming back from the sub arrays. So does that mean in your opinion these would be permissible to run along the aluminum extrusion up the rafter?

You can only run those conductors outside of a listed raceway within the array. Once you are beyond the array you need a listed raceway or other chapter 3 wiring method.

 

[Anode]

You can only run those conductors outside of a listed raceway within the array. Once you are beyond the array you need a listed raceway or other chapter 3 wiring method.

This is within the array (by my interpretation), once the conductors reach the top of the rafter, they immediately will transition to a wireway entering through weathertight fittings, and transition out of that wireway to conduit.

Is there a particular section of code that supports this:

You can only run those conductors outside of a listed raceway within the array.

Thanks again for all the help.

 

[SolarPro]

See 690.31(A) and 690.31(C)(1) in NEC 2014. Exposed single-conductor cable is permitted "within the PV array." Otherwise, you can use raceways and cables that are "specifically listed for PV systems" or "other methods included in the Code."

The requirements in 690.31(G) are also relevant to BIPV. Once you are "inside a building or structure," you have to put PV source circuits in a "metal raceway." Per the definition in Article 100, a raceway is "designed expressly for holding wires, cables or busbars."

In other words, you want to get into a listed raceway as soon as possible/practiceable.

(What kind of BIPV product is this?)

 

[Anode]

See 690.31(A) and 690.31(C)(1) in NEC 2014. Exposed single-conductor cable is permitted "within the PV array." Otherwise, you can use raceways and cables that are "specifically listed for PV systems" or "other methods included in the Code."

The requirements in 690.31(G) are also relevant to BIPV. Once you are "inside a building or structure," you have to put PV source circuits in a "metal raceway." Per the definition in Article 100, a raceway is "designed expressly for holding wires, cables or busbars."

In other words, you want to get into a listed raceway as soon as possible/practiceable.

(What kind of BIPV product is this?)

I'm ashamed that the answer was in 690 all along, since I specifically design pv systems all day every week of the year. However, I never hesitate to engage the forum here, even with simple questions, as it may help others along the way. You all are like a fountain of experience and knowledge, and that is invaluable. Thank you very much for your help.

The product is Prism solar, which the concept and direction of the canopy was by others (a skylight company), and it is our responsibility to simply make connections and tie this system in to a larger roof mounted sub array about 10 times the size. It is actually a pretty neat project.

 

[Anode]

One more question here as well.

Based on the notion that it is permissible to run the source circuit conductors in this aluminum extrusion (not in the structure), how should I go about making sure that the conductors in this space will not exceed any sort of fill ratio for the area?

Should I use a 20% rule based on the space in this extrusion?

The extrusion will have a removable cover to access the wiring if need be in the future, so this space is not left open to free air; it is an enclosed area. The most I expect to have in this area is 7 - 8 conductors, and my feeling is that there will be plenty of space, but how should I go about double-checking this, to what rule would apply?

 

[ggunn]

One more question here as well.

Based on the notion that it is permissible to run the source circuit conductors in this aluminum extrusion (not in the structure), how should I go about making sure that the conductors in this space will not exceed any sort of fill ratio for the area?

Should I use a 20% rule based on the space in this extrusion?

The extrusion will have a removable cover to access the wiring if need be in the future, so this space is not left open to free air; it is an enclosed area. The most I expect to have in this area is 7 - 8 conductors, and my feeling is that there will be plenty of space, but how should I go about double-checking this, to what rule would apply?

For the sake of prudence I would apply the standard CCC's in conduit derate. That said, however, most of us use #10 wire for source circuits, whose ampacity is generally way over Isc even with the heat adder on top of ambient, so it's probably a non-issue.

 

[Carultch]

For the sake of prudence I would apply the standard CCC's in conduit derate. That said, however, most of us use #10 wire for source circuits, whose ampacity is generally way over Isc even with the heat adder on top of ambient, so it's probably a non-issue.

I think Anodewas thinking more in terms of planning the physical space, as opposed to the electrical ampacity, but that is a good point as well.

I would suggest following the procedure for the wiring method that best matches what you are doing in the field. For instance, if it is something you are closing with a cover, treat it as a wireway. If it is something you are laying wire within, treat it as a cable tray. If it is something you are pulling wire through, treat it as a conduit with an ID equal to the circle you can fit within its cross section. If you use 20%, that should cover you in most cases.