Transition from roof to attic - (entering conduit)

[jeremylmartin]

I am getting ready to install a 9.9 kw system. (36 panels in 2 strings, solaredge optimizer, w/10 kw solaredge inverter) I think I have researched most every step but can't seem to find information about options to transition from open air pv wire under the array into the conduit that will go into the attic. I bought this product:

http://www.quickmountpv.com/products/conduit-penetration-flashing.html?cur=0

I hope to keep everything under the array for a cleaner look and less exposure. I'll have 4 wires (from the 2 strings) and the ground. I plan to use PV wire (10 awg) all the way to the inverter because I have a 250 ft roll and that'll be enough to do everything. I'll probably mount a box in the attic and use wire nuts to connect the run from the inverter to the attic with the run from the array to the attic. I might try pulling the wire the whole distance but seems like it might be easier to do it in sections.

My question is: Do I need a weather proof box with individual weatherproof entry points for each of the 5 wires to transition on the roof (under the array) into the metal conduit or can I install an elbow facing down and just run the 5 wires into the conduit that way. It seems that water won't be able to get in but not sure if that is to code or smart.

One other question: I pan to use 8 awg solid bare copper wire to ground each rail together and then once in the attic/metal conduit use the 10 awg PV wire to continue the ground to the inverter (has built in DC/AC off switch). Does this seem reasonable? I plan to mark each of the PV wires at the other end to make sure it is clear what wire is what.

[SunEagle]

I am getting ready to install a 9.9 kw system. (36 panels in 2 strings, solaredge optimizer, w/10 kw solaredge inverter) I think I have researched most every step but can't seem to find information about options to transition from open air pv wire under the array into the conduit that will go into the attic. I bought this product:

http://www.quickmountpv.com/products/conduit-penetration-flashing.html?cur=0

I hope to keep everything under the array for a cleaner look and less exposure. I'll have 4 wires (from the 2 strings) and the ground. I plan to use PV wire (10 awg) all the way to the inverter because I have a 250 ft roll and that'll be enough to do everything. I'll probably mount a box in the attic and use wire nuts to connect the run from the inverter to the attic with the run from the array to the attic. I might try pulling the wire the whole distance but seems like it might be easier to do it in sections.

My question is: Do I need a weather proof box with individual weatherproof entry points for each of the 5 wires to transition on the roof (under the array) into the metal conduit or can I install an elbow facing down and just run the 5 wires into the conduit that way. It seems that water won't be able to get in but not sure if that is to code or smart.

One other question: I pan to use 8 awg solid bare copper wire to ground each rail together and then once in the attic/metal conduit use the 10 awg PV wire to continue the ground to the inverter (has built in DC/AC off switch). Does this seem reasonable? I plan to mark each of the PV wires at the other end to make sure it is clear what wire is what.

Running the 5 wires through that LB conduit fitting is acceptable in most places provided the LB is sized properly for the number and size of those wires.

You should check with your local inspector to see what they expect and will approve. Some areas want a "combiner" or "junction" box on the roof for easy disconnection.

You will also need to run those DC wires from the array through your attic to the inverter in a metal raceway or conduit.

[sensij]

I am getting ready to install a 9.9 kw system. (36 panels in 2 strings, solaredge optimizer, w/10 kw solaredge inverter) I think I have researched most every step but can't seem to find information about options to transition from open air pv wire under the array into the conduit that will go into the attic. I bought this product:

http://www.quickmountpv.com/products/conduit-penetration-flashing.html?cur=0

I hope to keep everything under the array for a cleaner look and less exposure. I'll have 4 wires (from the 2 strings) and the ground. I plan to use PV wire (10 awg) all the way to the inverter because I have a 250 ft roll and that'll be enough to do everything. I'll probably mount a box in the attic and use wire nuts to connect the run from the inverter to the attic with the run from the array to the attic. I might try pulling the wire the whole distance but seems like it might be easier to do it in sections.

My question is: Do I need a weather proof box with individual weatherproof entry points for each of the 5 wires to transition on the roof (under the array) into the metal conduit or can I install an elbow facing down and just run the 5 wires into the conduit that way. It seems that water won't be able to get in but not sure if that is to code or smart.

The product you are looking for is a Soladeck. There are other options (including the product you bought), but it is a really clean way to make the transition you are describing without requiring a separate junction box and additional conduit.

One other question: I pan to use 8 awg solid bare copper wire to ground each rail together and then once in the attic/metal conduit use the 10 awg PV wire to continue the ground to the inverter (has built in DC/AC off switch). Does this seem reasonable? I plan to mark each of the PV wires at the other end to make sure it is clear what wire is what.

#8 is too small to run unprotected on the roof. 6 AWG is the minimum bare copper size that meets code. Otherwise, what you've suggested sounds ok, subject to normal conduit fill and ampacity considerations.


Edit:
You can see in the picture below how mine was done (non-Soladeck), with a junction box that mounted to the rail and then conduit to flashing like what you bought, before it was all painted to match the roof.

penetration.jpg

[jeremylmartin]

Thank you both for the great advice. That Soladeck product looks slick. I may have to order one and not use the other deal I bought. I'll be sure to get at least #6 bare copper for the ground. My plan was to use 3/4 EMT and I found a chart that shows fill capacity for THHN but from what I understand the PV wire has thicker insulation. Anyone have experience running 5 wires of PV #10 in 3/4 conduit? Maybe it is worth buying THHN for the run to the inverter so it'll fit easier in 3/4 conduit.

[sensij]

You'll need to look up the diameter of your specific brand of PV wire and use a calculator to see how it fits, it is not standard. Sounds tight to me.

[peakbagger]

I really liked the Soladeck on my install. I hung a midnight solar SPD from one of the conduit fittings with a 45 degree elbow to get it clear off the roof. Made a nice spot to tie all the wires together and I used the fuse blocks during the install.

[jeremylmartin]

That is a nice calculator tool. It came out at 56% which apparently exceeds the 40% allowable. I think it'll be cheaper to switch to THHN #10 rather than increase conduit to 1". Now I'm going to have all this extra PV wire. Thanks again for all the help.

[Ben25]

Definitely go for the soladeck. Also you should double check that the inverter has an AC/DC disconnect. The new ones have been only DC. Doesn't matter if you're mounting it next to a breaker panel, but otherwise you'll need a separate AC disco at the inverter.


Ben

[PVAndy]

Definitely go for the soladeck. Also you should double check that the inverter has an AC/DC disconnect. The new ones have been only DC. Doesn't matter if you're mounting it next to a breaker panel, but otherwise you'll need a separate AC disco at the inverter.


Ben

You may want to take a look at Zilla

We install hundreds of systems a year and prefer Zilla over SolarDeck

http://www.zillarac.com/Zilla/Electrical-XL-Flashing-Assembly.aspx

Andy

[jeremylmartin]

Thanks again for the great advice. I have another question: If my city allows it is there any risk or downside to have the panels come within an inch of the edge of the roof? I'm talking about the side edges, not the peak or end of the roof, though I'll be real close to both of those as well. I can see how wind could get under if it hung over any edges but seems like if properly mounted (I'm using Ironridge XR100) it will be fine right at the edge. I'm just trying to maximize my south facing roof section. Surprisingly the only info I can find online discusses the 3' setback required by the city but not much discussion about how close is wise if the city doesn't require a setback.

[foo1bar]

Surprisingly the only info I can find online discusses the 3' setback required by the city but not much discussion about how close is wise if the city doesn't require a setback.

A> Ask the firemen who (at least in my city) are the ones who would sign off on a waiver of that 3' setback.
B> Figure out how a fireman will cut a hole in the peak of your roof into your attic space if you have a fire, and make sure that it's easy for them.
(In my case it's pretty obvious - just go up the north roof face )

[peakbagger]

The prior poster got it right, check with the inspector. Technically there are not issues with ending the panels even with the edge or the roof. Overhangs are frequently add on rather than part of the structure so the mounting points should be tied into the roof structure. Most fireman want access to the ridgepole and about 3" down the roof line to ventilate the roof so they tend to get picky if the panels get near the ridgepole. Most firefighters tend to want to climb up the side of the roof over the end walls as they have less exposure to a structure collapse so that why they prefer a open lane on both sides rather than one up the middle.