Conduit and Wire - Roof Mount

[Solar_Duc]

I'm working on the permit drawings for my 10kw roof mounted system grid tied system with no batteries. I was originally designing a ground mount system which was simpler in regards to the wiring and conduit since all the panels were mounted together. I've switched to a roof mounted system now and I'm reworking the drawings/design. I'm designing a system with a single inverter and optimizers on a tile roof so I want to limit my penetrations for conduit.

It is my understanding that on a roof system with multiple arrays in different locations on the roof that I'll need to:

1. Run all wire that is not under the panels in conduit (rigid metal conduit).
2. Transition from the PV cable to THHN must be done through a junction box/conduit entry box.

See the attached single line diagram for reference, note that this is a progress drawing.... It seems the most efficient way to do this would be to run the PV cable as far as I can so that don't need to keep it in a conduit from start to end, I just need to run conduit from array to array. Or should I convert to THHN at each array with a conduit entry box, if I do this then it seems the entire run will need to be in conduit whether or not it is under the panel. The attached diagram shows the layout keeping PV cable to one junction box then switching to THHN (I'm still working on the conductor/wire schedule so ignore that.. I've also attached a roof layout with conduits in heavier line weight.

 

[JCSchwarb]

I'm working on the permit drawings for my 10kw roof mounted system grid tied system with no batteries. I was originally designing a ground mount system which was simpler in regards to the wiring and conduit since all the panels were mounted together. I've switched to a roof mounted system now and I'm reworking the drawings/design. I'm designing a system with a single inverter and optimizers on a tile roof so I want to limit my penetrations for conduit.

It is my understanding that on a roof system with multiple arrays in different locations on the roof that I'll need to:

1. Run all wire that is not under the panels in conduit (rigid metal conduit).
2. Transition from the PV cable to THHN must be done through a junction box/conduit entry box.

See the attached single line diagram for reference, note that this is a progress drawing.... It seems the most efficient way to do this would be to run the PV cable as far as I can so that don't need to keep it in a conduit from start to end, I just need to run conduit from array to array. Or should I convert to THHN at each array with a conduit entry box, if I do this then it seems the entire run will need to be in conduit whether or not it is under the panel. The attached diagram shows the layout keeping PV cable to one junction box then switching to THHN (I'm still working on the conductor/wire schedule so ignore that.. I've also attached a roof layout with conduits in heavier line weight.

I recommend running continuous solar “direct burial” UV rated wire from panels using MC4 connectors. You want to minimize connections. If outside panel, place in conduit. Your next junction should best be into a ground mounted fuse box. From there you can run THHN/THWN2 (90C temp rated) in conduit into your isolator quick disconnects and out in conduit to your inverter(s).

 

[Solar_Duc]

I recommend running continuous solar “direct burial” UV rated wire from panels using MC4 connectors. You want to minimize connections. If outside panel, place in conduit. Your next junction should best be into a ground mounted fuse box. From there you can run THHN/THWN2 (90C temp rated) in conduit into your isolator quick disconnects and out in conduit to your inverter(s).

Thank you that is what I was looking for.