PV Installation (Part 1) – Planning and Racking

Hello I'm Steve Sefchick and I'm Sarah Wilder and we're here today in the SolarWorld training room in Hillsboro, Oregon where we're going to show you the basic steps for installing a grid-connected PV system. So the three major components of a grid-connected PV system are the PV module, the roof attachments and racking and also the inverter. In this case we're going to show you how to connect to microinverter and a string inverter. All right, first things first – safety. Solar installers are exposed to the biggest hazards in the construction industry fall hazards and electrical hazards. So the first thing you want to make sure that you're qualified individual. Only qualified individuals should be installing solar arrays. In some states that means that your licensed to do it. We recommend that also you have contact hours with OSHA there's an OSHA ten and OSHA 30 that has 10 and 30 contact hours respectively and that really should be the starting point. So here we've got our fall protection system we've purchased a safety in a bucket from a big box store or local supply house the local safety supply house and comes with everything that you need.

You need to wear a fall protection system if you're exposed to a 6-foot fall hazard or greater. Here in the training room we're not going to be exposed to a 6-foot fall hazard so we're not going to be wearing the safety gear. The first step in the installation process is to consult your plans set. Then you're going to mark out the edges of the array on the roof. The plans will show module dimensions and where the array is located on the roof. Here we're centering the array from side to side on the roof for aesthetics and also to give us three foot firefighter access pathways on either side of the array and at the peak. Pathway requirements will vary by location so it's important to check with your local permitting department.

Array locations may also be affected by obstructions on the roof such as skylights, or vents, or objects that can shade the array like a chimney or nearby tree. We mark out the four corners of our array which will be two rows of three modules mounted in portrait orientation. We've centered the array on the roof and now we're going to find the shingle line that our attachments are going to be located on. First we're gonna to find the center of the rows. 66 inches of space for the two rows. We're gona mark the shingle row that our attachments are going to be located on. We chose this shingle line based upon the installation instruction mounting zones. Here we have 9.4 to 16.5 so this shingle row is in that zone I'm gonna mark it with a red crayon to differentiate from the yellow mark edges. There are multiple ways you can mount the solar modules to whatever racking system you're using.

At the end of the SolarWorld module installation guide there are figures showing allowable mounting zones for different racking configurations. Beneath the image you'll see the maximum allowable wind and snow loads for the designated mounting zones. The negative number will be your wind uplift and the positive number will be your combined wind and snow downward pressure. Since these loads are site-specific you want to confirm your design with your engineer. We found the shingle row for our flashings. The next thing we're going to do is find the rafters for our attachment points. There's three basic ways to do that. First one echo location – here we're looking for a change in tone to show the approximate location of the rafter.

Another way is to use a high-end stud finder and a third way that most people are probably going to use and is very reliable is to go into the attic and drill pilot bit up and then measure off of that rafter to the other rafters. Ok so here we are in the attic underneath the roof and one thing to consider is that if you are trying to find the rafters while on the roof you might not be able to find the exact center of the rafter and it's really important that your lag bolt hits the center of the rafter so that your PV system is properly anchored to the structure so if possible you're going to want to get into the attic and what you can actually do is drill up next to the side of the rafter so that you know where that first rafter is and then I can measure off of this point and see what the distance is to the next rafters.

Ok so here we are back up on the roof and here you can see the drill bit coming up from the attic at the edges of the rafter. So what i can do is simply mark three quarters of an inch over from that point to mark the center of the first rafter and then I can translate the dimensions that we measured in the Attic to mark the center of all the additional rafters.

We measure four feet from our first center of rafter location to our next two attachment points since the plan set denotes four foot spacing between attachments. We'll then use a long finder bit to verify that we actually hit the correct location and center of the rafter snapping a chalk line in between confirm locations is a great way to find attachment points in between. One thing to remember though not all rafters are going to be consistently spaced or perfectly straight especially in older homes. Ok so now that we've located all of our penetration points the next step is to install the roof attachments and the flashings.

So here I've got quick mounts composition mount flashing here and the first step is to clear away any nails or staples that might interfere with this flashing sliding up under two forces of shingles use this crab are here. Next step is to apply sealant. Here I've got an M-1 product and just do a nice horseshoe shape around the opening and then also apply some sealant to my hole. Slide this flashing up under the shingles. Preset my lag bolt in the hole and now I'm ready to drill this down. Now it's important to refer to Quick Mount's installation instructions for more information on how to properly install these, but Quick Mount recommends that you give this block slight angle to allow any debris to run off to not collected at this point right here. Now we use a correctly sized pre-drill bit for our lag bolts and we lay out the attachment flashings. Now we install the rest of the attachment flashings. You may find that it's safer to install each attachment flashing as you go so it is secured to the roof and doesn't present a tripping or fall hazard.

Next up is the racking Alright we've got our flashings installed. The next step is to get the rail up so the part that's in between the rail and flashing is this L-foot right here and as you can see we've actually pre-installed the t-bolt on the ground anything you do on the ground is going to save you a lot of time on the roof and this bolt right here is going to be the connection between the L-foot and the rail itself. So a Quick Mount flashing has a bunch of different washers you really want to get those in the right order so that you don't have any leaks. So we consulted our manufacturer's instructions as always and the first thing we're going to do is we're going to put this gasket in. Next thing is the L-foot and we go flat washer, cut washer and nut and you can actually install this so that the L-foot is uphill and have the rail on this side of it or you can rotate it and have the rail on the bottom side there's also a lot of flexibility here there's an open ground there that you can slide the L-foot up and down with.

Today we're going to install it so that the rail is on the downhill. Now you always want to be thinking about how to work most efficiently especially when you're up on a roof. So here i'm installing each L-foot individually but it might have been more efficient to install the L-feet at the same time as the flashing was installed. That would minimize the number of trips to each attachment point. How you choose to install will vary based on crew size and skill level just remember a little bit of thought and planning ahead of time can go a long way. Alright today we're going to be using SolarWorld Sunfix+ racking system for our installation.

The major components are the L-foot, the rail itself and then we have this splice bar for connecting different sections of rail together and we got a bonding jumper too that's going to electrically connect those sections rail together. And then here we have our top down clamp this will clamp the module to the rail and we have a t-bolt and this goes in the L-foot and it makes the connection to the rail so if you're going to be using other racking manufacturers products just make sure you consult their installation instructions because the tools and the hardware going to vary manufacturer to manufacturer.

Alright, we've got all the L-feet mounted on the attachments. Next step is to get the rail up. That's gonna be the part that supports the module. So we've got two grooves on the rail. We've got the one right here that's going to go into t-bolt topside for supporting module. We're going to loosely fit into the t-bolt The t-bolt has a little groove on one side that lets you know the orientation of that. We allow it little loose so we can slide it back and forth and get into the right position. There we go.

So here we're gonna be installing a single rail section because we have a short of row modules. If we had a longer row modules we'd be installing multiple rail sections and we'd need to mechanically and electrically splice the sections of rail together. The SolarWorld Sunfix Plus has a floating mechanical splice simply slides into the extrusion and you're going to put the other rail section in the splice and you're also going to need to bond the two sections rail together so we have a bonding strap here that slides into the front groove of t-bolts and you'll notice back here that i have one attachment point supporting the rail so every rail section needs to be supported by at least one attachment, two is even better and after you get all the bolts in place you want to make sure to use torque wrench to torque down the bolts to the proper specifications. Now we install each section of rail and measure off the edge of the roof to fix the location of the upper and lower rails. We then run a string between these rails and adjust the middle rail so everything is lined up.

Now that all of our rails are set in place we use a torque wrench to tighten up all the hardware to the specification in the racking installation guide. Alright here's a handy little trick you can take an extra rail, attach an L-foot to the top and then hang it off the top rail there, rest it on the bottom. You can bring up all the rails in between up to the same plane. It's a lot easier to do this now than it will be once you have the modules on the rails. Handy little trick. Now that we've installed all of the attachments and the racking the next step is gonna be to install the grounding system and this is to minimize the chance of any fire hazard or electrical shock hazard. So what we're going to do is attach these rail grounding lugs to the racking, uh to each section of racking and then run a copper ground wire between the different rail lugs and this is to bond all of the sections of rail together. And this ground wire is going to eventually connect to the grounding electrode system of the house.

Here we have a rail grounding lug and the way this grounding lug gets attached to the rail is by sliding this t-bolt into the side channel of the rail and then tightening it down. This rail lug has a grounding washer on the back of it with little teeth that will actually pierce the anodized coating of the aluminum wracking when it's tightened and then it has a side channel for the copper wire which will get inserted in there and then tighten down. So now we're going to install this grounding lug again in the correct orientation which is horizontal. We're gonna tighten this down here. Now we're going to install the copper wire and then finally it's important to torque the nuts down to the proper value in this case 12 pounds. Remember you want to use a torque wrench to tighten down all your hardware. Here this includes the rail lug to the racking and also the wire to the rail lug.

It's best to use solid rather than stranded ground wire up on the roof as stranded wire can get easily damaged when it gets tightened down inside the rail lug. Alright at this point we've grounded all the rails and it's time to bring the conductor's into the building. One way of doing it is with the standard off-the-shelf OD flashing. This is one of the most common misinstalled products out there. You want to make sure that you have it up under two courses of shingles for starters and also you don't want to ever bring flexible conduit into this because it can pull on the rubber boot right here and allow for water to get in. You can either put the weather head on top or you can run this directly into a junction box. Another option that we have here for bringing the conductor's into the building is this Solodeck flashing.

It's costs a little bit more up front, but it's going to save you a lot in terms of labor and it's going to aesthetically look really good, it just looks like a roof vent and it also doesn't have any rubber that's going to break down over time in the sun. So we've installed a core grip to bring the conductor's into. I've also drilled a little hole here for the ground wire to go in. You can see there's a lot of different options that you can mount onto this din rail and I've knocked out a hole that's going to go into the attic.

I've already cut out the shingles to slide it up into. Here we go lining up at knock out with the hole going into the attic. Looks good, now I gotta secure it to the deck and put a couple screws inside here. Finally I'm gonna put a little sealant over the screws. And there you have it. For more information visit our website at www.SolarWorld.com or if you have any questions you can send an email to trainingUSA@SolarWorld.com.

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