Residential Solar Mounting Solutions Guide 2019: Situations and Solutions

solar mounting illustration

Solar installers face jobsite annoyances every day. Awkward roof space. Plastic baggies of tiny components. Missed rafters. And so on. Death by a thousand racking cuts. Luckily, for all of these situations, there is a mounting solution out there to make your life easier.

Micro but Mighty

It’s not the size of the flashing that counts, but the system that comes with it

QuickBOLT Mounting Kits

QuickBOLT is a cool new name and logo, with a newly registered trademark for its solar mounting product innovation, but don’t be fooled: all of it is tied to a company and system you already know with decades of roofing and solar experience. Yes, formerly known as SolarRoofHook, QuickBOLT is the solar wing of Quickscrews International Corp., and its one of a kind Microflashing system is a component of its QuickBOLT and Low Profile QuickBOLT Mounting Kits.

The QuickBOLT is the world’s first and only UL Certified Microflashing mounting system, which seals roof penetrations and can be installed without lifting shingles or removing nails and staples. The QuickBOLT with Microflashing has been installed over 600,000 times with zero leaks.

With its new branding and new trademark in hand, we thought it was time we reintroduce you to the company’s strategy and how its system works.

 

Situation

Holes must be made in the roof for a solar installer to mount an array. Those holes must be sealed in some manner, otherwise the roof will leak. An installer who doesn’t use flashing methods greatly increases their risk of a leaky roof. Plus, International Building Codes require flashing to be used on residential rooftop solar. Flashing is typically sold as part of the mounting system. Mounting manufacturers design flashing products that, first and foremost, prevent leaks. Factors like ease of use or install speed more often come second.

QuickBOLT’s goal from the outset was to improve upon the various flashing methods out there with a flashing product design that would prevent water from entering the penetration while reducing the installer’s time up on the roof.

Key Considerations

In the late 2000s, minor innovations in flashing technology took place as mounting manufacturers began shifting away from “standoff” type mounts and toward mounts that integrated traditional flashing into the design. Both rubber bushed flashing and elevated flashing were became designs which added an extra layer of security to protect against water entering the penetration.

“30 years ago, Installers were mounting L-Feet directly to the roof with sealant alone,” says Jared Wiener, executive vice president at QuickBOLT. “In efforts to reduce leaks, the solar industry adopted flashing products that were more effective at redirecting water away from the hole—but often at the expense of voiding the roof warranty.”

Most of the flashing products used in the past included 12 in. x 12 in. pieces of metal to cover a hole that is typically only 5/16-in. in diameter. Installers ended up cutting the material to fit according to their array or simply to remove excess metal. Industry “best practices” were to lift up the shingles and place the flashing product underneath the 3rd course or layer.

The idea was that even though material and labor costs increased, these flashing products would prevent water from entering a penetration. But leaks still happened. Solar installers were unknowingly voiding roof warranties to install solar, becoming responsible for repairing leaks they could have prevented.

“We spoke with installers and roofers around the U.S. and learned that if we could eliminate the need to lift shingles, then solar installers could save a minimum of 30% of the time it takes for a typical solar install job,” Wiener said. “By providing installers with Microflashing, we were able to find the sweet spot between the simple L-Foot 30 years ago and the expensive flashing products of the 2000s.”

Solution: Microflashing

The patented QuickBOLT Mounting System debuted in 2010 for asphalt shingle roofs, which includes what is now properly known as Microflashing. The design of the system addressed the problems installers were facing: voiding the roof warranty by lifting shingles, speed of install, and reducing costs.

The QuickBOLT Kit consists of just three components: a custom hangar bolt, Microflashing, and a flange nut. When installers drive the bolt down, the collar compresses the Microflashing onto the roof, closing the penetration and creating a watertight seal. Any racking system can then be mounted by connecting a any type of bolt to the L-Foot. Installers have fewer components to carry onto the roof and can install the system in less than 60 seconds. The Microflashing is large enough to cover any other holes that might be made from missing the rafters, but unlike traditional flashing methods, installers no longer have to pay for extra, unused material.

What separates Microflashing from previous flashing methods is its placement. Before, installers would lift up the shingles and slide in the flashing underneath. Not only is this time consuming, but it potentially voids the roof warranty and increases the installer’s risk. Instead, Microflashing is designed to be placed directly over the shingle. Water is redirected around the washer just like other flashing methods — but it is significantly easier for installers to use and completely closes the penetration.

This innovation in flashing methods has given installers a new way to install more solar and increase profits.

Notes: QuickBOLT Patent #8448407. Microflashing is a registered trademark. © Copyright 2019. All Rights reserved Quickscrews International Corporation.

Situation

Transporting, cutting and maneuvering the mounting rails will be cumbersome.

plp power disk

Key consideration: Where and how to place solar mounting rails on residential rooftops.

Solution: The POWER DISK from Preformed Line Products (PLP) is a solar mounting system that can be placed anywhere on residential rooftops and does not need to be secured to rafters. Featuring a rail-less design, easy height adjustment and integrated grounding, the POWER DISK is a simple yet cost-effective solution for residential solar applications. What sets this mounting system apart is the roof deck mounting feature which allows for an easier array layout and faster PV module placement. The roof grip fasteners, sealing washers and pre-applied butyl mwastic are all included to provide a secure and reliable roof attachment. The benefits of POWER DISK:

  • Flexible. Modules can be set in portrait or landscape format
  • Adaptable. Attach anywhere on the roof
  • Compatible. Fits most framed 60- and 72-cell modules
  • Quick installation. Comes pre-assembled
  • Built-in electrical grounding. Grounding clips are integrated in the mount

Situation

Steep roof and a large system, a solar array highly visible from home’s primary gathering place.

Ecolibrium EcoX Universal Railess Racking system

Key considerations

  • Maximum fit on roof, same part count in landscape or portrait
  • Low part count for easy and safe installation
  • Exceptional aesthetics from any angle

Solution: Use a safe, fast rail-less solution that eliminates handling 20-ft rails on a steep roof and enables no-reach, module drop-in. Ecolibrium’s EcoX Universal Rail-Less Racking eliminates the need for 20-ft rails and the cost, risks and unsightliness of rails. The EcoX reduces attachments needed by 33 percent and uses 65 percent less aluminum to secure the array. Its no-reach-over panel drop-in design is a key feature, particularly on steep roofs. Components are universal to fit any module frame size, which allows installation to continue even if the module is changed. The design is flexible, resulting in a portrait orientation that fits the roof beautifully. A low-profile, finished look provides exceptional aesthetics for the highly visible location. Cost-per-watt is low.

Situation

Solar roof mounts for a standard composition shingle roof in Greenwich, Conn.

Ecofasten’s RockIt system

 

Key consideration: It’s a typical 35° snowy Mid-March day complicating jobsite conditions, so installers want to move quick.

Solution: The simplicity of Ecofasten’s RockIt system allows the installation team to complete the nearly 12-kW project in 7 hours, enabling installers to escape the bitter weather conditions in as short a time as possible. RockIt has a one-tool approach and only six components, much fewer than typical rooftop mounting systems. Furthermore, the rail-less RockIt solution allows for fewer roof penetrations compared with a rail-based system, further cutting down installation time and product parts. The installation team comments that they were able to bring all materials up to the roof quickly, with products being packaged in small boxes.

Situation

A 7-kW PV system installed on a regular comp shingle roof, 18-degree pitch with 24-in. OC rafter spacing. Twenty-four REC 295 modules at three rows of eight modules. Due to zoning and maximum rail spans, there are 30 roof attachments.

SnapNrack Ultra Rail System’

Key consideration: Time on and off is a priority as the crew is required to complete two jobs per day.

Solution: The SnapNrack Ultra Rail System’s snap-in strategy is featured throughout the installation process — from the the snap-in Ultra Rail Mounts to the module clamps to the wire management accessories. The lightweight rail and pre-assembled components allow for easy transportation on and off the roof. All components are installed with a single tool, a ½-in. socket, eliminating the need for more parts and pieces on the roof. An installation team of four can install this 7-kW system in less than 4 hours, allowing them to get two jobs done and still get home in time for dinner with the family.

Situation

A typical existing asphalt roof for a retrofit PV installation.

Roof Tech MINI

 

Key consideration: The installer wants to secure the mounting system to the roof without having to undo the existing seal of the roof shingles or affect the roof warranty.

Solution: Because of its simplicity and the ICC-certified “flexible flashing” system, the Roof Tech MINI is fastened to the roof without the need to damage the seal of the existing shingles. This approach does not impose a damage of the underlayment nor does it require the removal of nails needed to secure the asphalt shingle roofing. By comparison, installing a traditional metal flashing system on an existing asphalt roof requires the breaking of the seal between shingles and can cause additional damage to the underlayment through scratching it with the metal flange. Also, the opening of a hole on the underlayment from pulling an existing nail used to secure the shingles above in order to slide the upper metal flange into the third course also poses another quality issue. RoofTech says it avoids violating the roof warranty while allowing for a quicker installation time. Additional time is saved in comparison to lag bolts, due to the use of wood screws which don’t need a pilot hole.

Situation

A homeowner getting an asphalt shingle roof replacement requests a quote for solar but express minimal interest in rack and panel systems feeling it’s a ‘dated’ look.

Apollo II solar roofing system

Key consideration:  Losing this sale by only offering traditional rack and panel solar.

Solution: The Apollo II solar roofing systems from CertainTeed are engineered for seamless integration with new or existing asphalt shingle roofs. Each all-black solar shingle offers 63 watts of rated power, and at 1.22 in. thick, provides a sleek, low-profile aesthetic. Apollo II solar shingles attach directly to the roof sheathing with standard deck screws, feature a concealed wiring design and can be installed in any wind zone (including Florida’s high velocity hurricane zone). Dynamic flashing allows for flexibility in rooftop system layout, with water channels and raised fastener locations providing superior protection against water intrusion.

Situation

A small 17-kW commercial job at Canterland Farms near the Yamhill-Carlton American Viticultural Area in Oregon.

SunModo’s 1-in. EZ Standing Seam Clamps

Key consideration: It can be a challenge for installers to fasten standing seam clamps onto the roof seams because many clamps have attachment screws that are too close to the flat roof surface.

Solution: SunModo’s 1-in. EZ Standing Seam Clamps can be attached to a wide variety of seam profiles. The EZ Standing Seam Clamps use set-screws to compress the seam material against the opposite wall of the clamp. The preassembled set-screws can be attached on the vertical leg of the clamp or on the adjacent leg with its 10-degree angle and hook for greater gripping. The clamps are super easy to install, and the upward angle of the set-screws leaves plenty of work space between the drill and the roof. The oval end set-screws and proper torque ensures the protective coating of the roof seam is not damaged during installation.

SunModo also offers 2-in. EZ Standing Seam Clamps which can be installed in-situ at the desired seam attachment location. These clamps are a two-part assembly and uses the same upward angled set-screws to secure them firmly to the roof; no more sliding clamps up the roof line.

Situation

Sloped metal roof on residential and commercial buildings are mostly standing seam, R-Panel trapezoidal and corrugated metal roofs, but due to different profiles from different manufacturers, there are various brackets available for solar installations.

MageBracket R

 

Key consideration: Save time wasted by checking out each roof profile and settle on only one or a few brackets that fit most of the metal roofs.

Solution: The MageBracket R has an angle-adjustable bracket that fits most of the popular R-panel trapezoidal metal roofs. The bracket has two adjustable parts that can rotate to fit the rib with different angles. Therefore, installers don’t need to check out the roof profile first, then look for the right bracket and then wait for the bracket to arrive. Instead, they can stock just one bracket to save money and time. Similarly, MageBracket CH is also an angle-adjustable bracket that fits most corrugated metal roofs with rotating parts for different angles. For low-profile corrugated metal roofs of only 1/4 in. to 1/2 in. tall, MageBracket CL is width-adjustable and fits most low-profile corrugated metal roofs.

Situation

Installer is struggling to find structural members. They are drilling enough probing holes to infer center from a series of hits and misses. Stud finders cannot read through layers of roofing material and plywood and other high-tech devices have given mixed results.

RafterEye LLC Clampster,

 

Key consideration: Locating rafters without creating more penetrations than are needed to install the PV system.

Solution: Tucson-based RafterEye LLC just launched Clampster, a rafter center locating tool, to assist PV installers and others in rooftop attachments. Clampster — which can be used in a variety of construction applications such as exposed beams, porches, navigable attics, skip sheathing, log rafters — works through any roof type except steel. The clamp portion of Clampster grips the rafter just below the deck, and it works by forming a magnetic field around and through a rafter or truss. A rooftop worker reads the magnetic field, which points precisely to rafter center before any penetrations are made. The magnetic field can be read through up to 6 in. of insulating material that may be present (above or below the roof deck) between the available portion of the rafter and the roof membrane. There is no need to infer from one or both edges. Workers move rapidly, precisely locating one attachment point after another before any penetrations are made.

Situation

A rooftop that’s not quite near replacement but getting there. Homeowner wants a solar system now, but also wants to avoid the hassle of removing/reinstalling at replacement time.

APA Solar Racking Pre-Engineered Kit

Key consideration: This is a home in the Northeast, which is notorious for rocky soil.

Solution: APA Solar Racking has a Pre-Engineered Kit that’s a concrete-free solution for project sizes under 150 kW. This system is custom to any two panel increments. It comes with every part necessary for the racking, and 10 kW can be installed in 4 hours with a skid steer and auger attachment. In lieu of concrete, APA offers three types of foundations: helical anchor, geoballast and ground screw. A ground screw is best used in rocky soils, whereas a helical is ideal for soft organic soils. A geoballast is used when the soil is non penetrative.

Situation

A farm with high electric load and a 15-kW AC capacity cap in place. There is a time-of-use (TOU) rate schedule in place from the utility, with the higher rate between 4 p.m. to 7 p.m. There is an open view of the sky E,S,W.

AllEarth Solar Tracker

 

Key consideration: The roof is not great from a structural or orientation perspective, and a ground-based solution should make best use of land.

Solution: The AllEarth Solar Tracker is a grid-tied, dual-axis solar tracker ideal for both commercial and residential settings to take advantage of the sky E,S,W to get maximum production. Here, there would be minimal if any shading from buildings, trees, etc. due to the open farm field. Any permit limitations with an AC limit (vs. DC) will be an advantage for this tracker which produces more power (kWh/kW). The tracker system can be sized to that 15-kW cap and produce up to 45 percent more energy than a similarly sized fixed-tilt system. All of this takes up less room compared to fixed, helping the farmer get the most yield from their land. Under and between the trackers is still usable land for most agricultural needs. Due to the increased afternoon/evening production of the tracker, more kWhs are produced during the TOU, which best offsets costs.

Situation

A new crew member is on a presidential shingle roof installing flashings and L-feet. He rips open a plastic bag containing EPDM washers for the lag screws, and several fly out, rolling off the roof. He then places a flashing over the uneven presidential shingle tabs and installs the lag with an impact driver.

Pegasus’ Comp Mount

 

Key consideration: Quality control. When installing on un-even shingle tabs, such as presidential shingles, 1) press-fit flashings can crack at the water seal; 2) flashings with deck-level water seals may not seat fully against the L-foot, and 3) adhesive reliant flashings may not seal to the shingles around the roof penetration. All of these scenarios have leak potential.

Solution: Pegasus’ Comp Mount has several features to ensure high-quality, lasting and consistent installations. The All-In-One kit packaging has no plastic bags and includes all flashings, L-feet, lags and EPDM washers so there’s less chance of forgetting parts at the shop. The EPDM washers come pre-installed onto the lags to ensure they are installed every time and not lost in gutters. Pegasus’ Comp Flashing has a 0.7-in.-tall cone formed from a single piece of metal, meaning there are no deck-level washers or press-fit pieces to break and allow a roof leak. Pegasus’ L-foot elevates the water seal 0.9-in. above the roof surface, diverting much of the water flow. Finally, a bonded EPDM washer at the lag head acts as a final defense against water intrusion.

— Solar Builder magazine

Solar System Wire Management Buyer’s Guide 2019

hand holding wires

We humans have a lot in common with wires. We are vessels of energy and information that need grounding for stability. When put in situations that best suit our skillsets, we thrive. We are also prone to getting tangled up, stuck in our own way. We can be fragile. We don’t like the heat! Or rodents! And yes, like it or not, our appearances do matter.

This Wire Management Buyer’s Guide is here to help us humans have a better working relationship with our friend the wire. We asked every wire management expert we know for advice on avoiding common wire management issues, eBOS trends that are saving time and money and which new products solar installers should consider for certain applications.

Here’s our 2019 Solar Inverter Buyer’s Guide, if you missed it.

CAB Solar Cable Management

CAB Solar Cable Management

Key feature: Saves time, money by simplifying large-scale installs

CAB Solar Cable Management has a new, patented Integrated Grounding system. It utilizes copper composite messenger wire in place of the standard system’s galvanized, and it can act as the EGC and GEC. The new system uses grounding hardware on the L-brackets that allows them to bond the messenger wire to the pier and eliminate jumpers at each pier. This system saves both labor time and money. It has proven to be a huge benefit. It is safety listed by Intertek to UL 2703, and the L-brackets are UL 467 compliant. Engineering reports on the system and installation best practices are available.

Shoals Big Lead Assembly

Shoals Big Lead Assembly

Key feature: Eliminates combiner boxes

The BLA is an above-ground wiring solution that eliminates traditional combiner boxes and issues related to blown fuses that are commonly experienced in operation. By utilizing a BLA trunk system and disconnect boxes, installers can reduce their installation costs by more than 50 percent with this pre-fabricated solution. Owners and developers also benefit from the BLA system as there are significantly fewer points of failure throughout the system, reducing lifetime O&M costs.

Heyco HEYClip

Heyco HEYClip

Key feature: Cables tucked inside the module frame

The Heyco HEYClip RevRunner Cable Clip is a 304 stainless steel PV module clip that holds up to 2x cables that are between 0.20 and 0.33 in. in diameter and clips onto module frames that are between 0.06 and 0.13 in. thick. When used on panels within that range, these clips survive a 15-lb pull-off test and have superior side-to-side cable retention. The main benefit of this clip is that it positions the PV cables so that they are tucked up and underneath the PV module frame — which means they are out of sight for an aesthetically pleasing installation.

Solar Snake Max

Solar Snake Max

Key feature: Quick, code-compliant utility-grade cable separation

Solar Snake Max is Snake Tray’s new patented cable management system for high-voltage, utility-grade installations. The easily snapped together elements allow for code-compliant cable separation that can cut construction cycle times in half. Cables install with snap together components, no tools required or field fabrication. Solar Snake Max quickly mounts to any style of vertical pilings or poles and maintains code compliant separation of power cables up to 2 KV. Snake Tray products are manufactured in the United States.

Heyco Tite Liquid Tight Cordgrips

Heyco Tite Liquid Tight Cordgrips

Key feature: Designed for the Enphase Q Cable

Two new cordgrips now accommodate the Enphase Q Cable — M3231GCZ (1/2 in. NPT) and M3234GDA-SM (3/4 in. NPT). The 1/2-in. version provides liquid-tight entry for one Enphase Q Cable (0.24 in. x .38 in.) The 3/4-in. version provides liquid-tight entry for up to two Enphase Q Cables and an additional .130-in. diameter hole for a No. 8 solid grounding cable. The 3/4-in. version utilizes Heyco’s skinned-over technology, so any unused holes will retain a liquid-tight seal.

Stäubli Reusable Sealing Caps

Stäubli Reusable Sealing Caps

Key feature: Protecting unmated connections

MC4 connectors are rated for IP68 when mated. When they are un-mated, MC4 connectors need to be protected from the environment, such as moist, dirt and even insects to ensure the long-term reliability and safety of the MC4 connectors. This reusable sealing cap by Stäubli will protect unmated MC4 connectors from moisture or dirt during installation or repair. This way, you don’t have to worry about the reliability of the connector. Other situations when a sealing cap can be useful: leaving a job unfinished until the next day, unexpected rain delay and repairing an old system.

TE Connectivity’s SOLARLOK PV Edge

TE Connectivity’s SOLARLOK PV Edge

Key feature: Junction box mounted on the edge of a PV panel

Glass-to-glass photovoltaic cells continue to increase in efficiency, fall in price and grow in popularity. TE Connectivity’s new SOLARLOK PV Edge, a decentralized junction box that can be attached to glass-to-glass photovoltaic panels without drilling holes, aligns to this new market. This small junction box can be positioned right on the edge of the glass to prevent shade falling on the cells on the rear side of the panel. The junction box has a flap design, which protects the foils while facilitating attachment to the PV panel. The flaps on the box are available in different shoulder heights to fit panels of diverse thicknesses. Other features of the new junction box include a lid with cooling ribs to improve heat dissipation, elimination of X-connect to facilitate layouts and shorter foil lengths and connections.

Wiley ACC-F4F Clip

Wiley ACC-F4F Clip

Key feature: Two attachment points, perfect for trackers

The WILEY ACC-F4F wire management clip is made of corrosion resistant 304 stainless steel, which makes them durable, long lasting and reliable for all environments. The ACC-F4F is easy to install and slides 90° onto module frames and purlins of various thicknesses. Two attachment points make this clip a perfect solution for trackers and high vibration or high wind applications. The ACC-F4F accommodates 1 to 4 PV cables up to 8.0 mm in diameter. Edges on the clip are rolled up and away from the wires to give additional protection to the cables against insulation damage.

SolarBOS AC Combiner

SolarBOS AC Combiner

Key feature: Cost effective AC combining

SolarBOS AC Combiners provide a safe and cost effective alternative to AC breaker panels. Individual fused inputs facilitate string inverter output aggregation. Incorporating bi-directional fuses eliminates the need for expensive breakers that must be back-feed capable. Fuses also offer a high interrupt rating as standard, commonly 200kAIC, while a breaker’s cost increases drastically as the interrupt rating increases. SolarBOS AC Combiners support all string inverters and are highly configurable to fit any application. They are listed to UL-508A and rated for 600VAC. Available options include integrated output or input disconnect switch(es), transient surge suppression, auxiliary mini breakers, neutral terminals, etc. Custom solutions are available upon request.

Solar Raceway

Solar Raceway

Key feature: Aesthetics plus snap-in cover

Solar Raceway is a 100 percent lay-in system that quickly snaps together and allows for testing of continuity within the system. Once the wiring is complete, simply snap the cover over the tray. The Solar Raceway increases installation speed and provides an aesthetic appeal that adds to the solar installation. Inspectors can effectively assess the system and allow for installers to move on to their next project. Solar Raceway’s applications include: commercial roofs, carports, ground mounts, solar trackers and residential installs. The product is available in both aluminum and PVC.

HellermannTyton Locking Clamp

HellermannTyton Locking Clamp

Key feature: Allows for one-handed installation

The Locking Clamp is ideal for fastening wire and cable bundles to panels. Its unique fir tree design holds tightly in pre-stamped hole sizes from 9×12 mm to 9×14 mm. The locking clamp mechanism dynamically fits various bundle sizes, while an integrated cable tie saddle allows installers to add additional cable runs. The clamp is manufactured from an impact-modified Polyamide 6.6 material for increased flexibility, heat resistance and UV stabilization to deliver years of dependable performance. It is easy to install and operate with a single hand and does not require tools, saving time and labor costs.

Nine Fasteners NFI-Hanger

Nine Fasteners NFI-Hanger

Key feature: Opening/closing metal hanger

Nine Fasteners’ newest product, NFI-Hanger, was designed specifically for large-scale ground-mount solar installations. Made in the United States, this wire form simply slides into a small hole in the panel frame and is capable of holding 20+ wires at a time. Produced out of hard-drawn galvanized steel, the NFI-Hanger is able to be opened and closed. The NFI-Hanger is durable in all climates and is currently undergoing testing to be certified to UL standard 1565 for “Positioning Devices within a Solar Installation.”

EcoMount Inverter Kit

EcoMount Inverter Kit

Key feature: Minimizes inverter footprint

Ecolibrium’s EcoMount Inverter Kit is a ballasted rooftop inverter mounting solution that simplifies and streamlines rooftop inverter deployment. Modular design minimizes the inverter rooftop footprint, allowing installers to meet NEC 690.12 rapid shutdown requirements without decreasing module density. The 1 and 2 inverter kits can be combined to fit project configurations. EcoMount is compatible with all major inverter brands. The system provides flexibility and simplifies logistics and installation.


Trend Watch

Labor Savings

“eBOS is becoming the most expensive component of a system, and labor is a huge part of that. Any time EPCs can prefab work in the shop when it comes to wire harnesses or combiner box work, it saves money out in the field where mistakes are more likely, and labor is almost always more expensive. But designing wire management components that take an assembly line approach to the field helps save on labor and reduce error during installation.” — Nick Korth, HellermannTyton

Longer AC Wire Runs

“Installers are running PV wire directly to the inverter location due to rapid shutdown requirements and the wiring advantage inherent in high DC voltage systems. Mounting the inverter next to the array is shortening DC wire runs and increasing AC wire runs. Installers are meeting this challenge and finding some advantages in eBOS and installation efficiency. Inverter mounting products are designed to enable the inverter to be mounted close to the array and cable tray to bring PV wire directly to the inverter.” — Jonah Coles, Ecolibrium Solar

More Than Four Wires

Solar installers are gravitating toward practices that result in higher numbers of PV wires running in parallel paths. This results in the need for wire management solutions that can accommodate four or more wires for simplified installation. Increasing the number of wires running in parallel is not a problem as long as wire management solutions are used to support the wires at proper interval distances.” — Sarah Parsons, Wiley.

Steel Clips are Back

“Several years ago, installers and contractors were shying away from stainless steel clips, not so much because of the cost compared to a cable tie, but because installers felt the stainless steel clips had too sharp of an edge to be used with PV cable. There were concerns these installations would experience some cable abrasion over an extended period of time, so installers simply didn’t use them. Fast-forward to today, and almost every PV module clip manufacturer ‘coins’ or ‘tumbles’ the edges of the clips to mitigate any abrasion. With that issue removed, PV module clips have great panel retention and accommodate a variety of cable diameters, making them an excellent choice in wire management — most also come with a 20-year warranty, something you won’t see with a standard UV rated cable tie.” — Tom Marsden, Heyco.

— Solar Builder magazine

Wire you doing that? Top four solar installation wire management issues

solar panel wires

1. Cross-mating

Cross-mating, which refers to the plugging of connectors from different manufacturers (between modules to optimizers/microinverters, modules to field-connectors, optimizers to field connectors or field connectors to the BOS system) is one of the most common PV wiring mistakes. In fact, the EU-funded Solar Bankability Project’s Failure Modes and Effects Analysis (FMEA), which sourced data from over 1 million documented insurance claims, showed that “different kinds of connectors” (cross-mating) had the highest risk potential in PV installations, and it wasn’t even close.

The reason for the risk here is connectors from different manufacturers have different dimensions, materials and engineering tolerance. The slight variation between different manufacturers can result in higher contact resistance (heat), water intrusion or unexpected deterioration of contact or plastic parts.

“Each connector has different critical dimensions and even using the most precise calipers to copy connectors still doesn’t guarantee a secure connection,” says Dean Solon, CEO and founder of Shoals. “Secondly, these connector manufacturers do not always utilize the same metals or procure their contact terminals from the same vendor. As a result, mixing dissimilar metals will unquestionably lead to thermal events [read: fires]. Pre-fabricators or field installers should use the opposite polarity from the same connector manufacturer used on the module datasheet. If it is not explicitly stated what type of connectors are being used on the module datasheet, reach out to the module manufacturer to identify.”

UL1703/6703, IEC 62548 and IEC 62852 (EN50521) testing does not allow for cross-mating. The good news is this is an easy problem to avoid during project planning. When designing or purchasing modules, field-connectors, inverter and optimizers and BOS systems, one needs to make sure that all connectors are coming from the same manufacturer. If you are using connectors labeled “MC4 compatible,” be sure to obtain a written statement from both manufacturers.

We have more on this topic right here.

2. Skimping

One of the most common issues in solar installations occurs when wire management is seen as an optional expense or somewhere to save on installation costs.

“The long-term system and maintenance costs that result from poor wire management practices far outweigh the effort required to implement a proper solution,” notes Sarah Parsons, Wiley product manager at Burndy. “Supporting PV wires at required intervals with listed solutions made from environmentally rated materials [such as stainless steel or UV-rated polymer] is the only way to align the lifetime of the wires with the intended system lifespan.”

This goes for the cables too. Jeff Wang, business development alternative energies – North America for Stäubli Electrical Connectors, recommends using only black XLPE cables and tin-plated copper cables.

“Color cables don’t survive the UV for the lifetime of PV system,” he says. “Incorporating carbon black in polyolefines greatly increases the UV resistance, and carbon black acts as UV absorbent and screens the polyolefine from the damage of UV lights. Bare copper starts to react violently with oxygen when temperatures reache 90 degrees. It forms copper oxide and greatly reduces the current carrying capacity of the wire. In outdoor environments where there is humidity and high temperature, tin-plated wire is the sure choice.”

3. Misapplication of components

Similar to No. 1, but more specifically: Understand the details of securing wire safely or choose a fastener that is tolerant of a wide variety of installation methods. For example, when putting metal-coated or plastic ties through sharp module mounting holes. With low-cost plastic ties, you should know exactly what you are getting as a system designer, which is a solution that could last as little as a few months. A metal coated product can lead to far greater damage than just product failure, like wire damage.

“In choosing a particular material or type of wire management component, metal tends to be more forgiving to install but less forgiving to the cable if installed improperly,” says Nick Korth with HellermannTyton. “Plastic wire management runs the opposite, requiring more care to design and install but is ultimately kinder on cable insulation. These considerations are an important part of your wire management strategy to ensure a long-term solar installation.”

Heyco sees a lot of installations where side-to-side cable retention cannot be achieved simply because of the mechanics of the part being used. For example, a standard cable tie is only going to provide so much side-to-side cable retention before it begins to sag throughout the array. Most PV module clips come with a unique spring retention tab that accommodates a variety of wire diameters while still providing side-to-side retention on the cable.

In large-scale applications, trends of higher voltages and the use of more string inverters out in the field call for a complementary update in wire management.

“Solar installations are now carrying energy as high as 1,500 volts with current approaching 1,000 amps, and it is critical for life safety issues to properly house the power cables to ensure a safe working environment for the solar technicians,” says Roger Jette, president of Snake Tray. “With more inverters in use, AC and DC cables need to be carried through a cable management infrastructure versus using hooks.”

4. Not planning for landscape

Module manufacturers are designing positive and negative leads anticipating they will be installed in portrait, though most rooftop installations are in landscape. Some 72-cell modules are manufactured with leads that do not reach adjacent modules in landscape, making it impossible to string a row together.

“These short leads force installers to wire in columns on a landscape rooftop system,” says Jonah Coles, product solutions manager with Ecolibrium Solar. “In this situation, choose a racking system with built-in features to secure wires across the inter-row space. This will make stringing columns as easy as stringing rows.”

Another challenge is that dual junction boxes with a short lead on each side of the module are becoming more prevalent. This makes wiring especially challenging when using optimizers and microinverters because both leads need to be brought to the optimizer or microinverter, which also makes wiring in landscape more difficult.

“Consider these factors when choosing modules. Make a string map to organize the wiring path based on the module you are using,” Coles says. “Then choose a racking system with flexible wiring options and have your racking solution quoted to include wire clips. These planning tips will avoid delays by providing installers with a solid plan and the appropriate material to get the job done.”

— Solar Builder magazine

Four energy dense solar mounting systems for C&I rooftops

SunModo SunBeam

sunmodo

As a permanent part of the building and roof structure, the SunBeam system eliminates any abrasions, moss build up and need of system removal for roof repair or re-roofing. In addition, it provides shading of HVAC equipment, increasing efficiency and faster temperature response. Twenty-year warranty.

Material: High-grade aluminum and 304 stainless steel hardware. Anchor-only attachment.

How it maximizes energy density: The SunBeam system elevates above obstructions such as HVAC, pipes and vents. By spanning over roof obstructions such as HVAC, pipes and vents, the system takes full advantage of the available roof surface thereby maximizing the PV system size. The system can be easily adjusted to account for the multiple roof pitches on site.

Everest Solar D Dome R²

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The D Dome R² system is an east/west commercial flat roof solution. The third generation of this product is now rail-less with only five major components and minimal hardware. It sits at a fixed 10-degree pitch and allows for 3.5-in. inter-row spacing. Twenty-year warranty.

Material: Aluminum, ballast with attachment optional. The ballast blocks sit under the panels.

How it maximizes energy density: Everest Solar Systems believes east/west systems are more efficient south of the tropic of cancer. First, an east/west system practically eliminates inter-row spacing which allows more modules on the roof, thus increasing module density. On one internal study, Everest compared a the production of a 10-degree south-facing system with its east/west system in southern California at different azimuths. The south-facing fit 88 modules and had a 14 percent decrease in at the 225-degree azimuth. The D Dome R² system reached 108 modules in the same space and had less than 0.1 percent change between all azimuth angles.

Solar Mounting Solutions

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SMS Racking consists of only three major parts that arrive with all hardware pre-inserted allowing for quick single tool installation. The THRU-ITT integrated wire management system allows wiring to remain organized and protected by running wires east-west and north-south internally. Since this racking design does not rely on the panel for integrity, installers can complete racking and wire installation independent of the panel. Twenty-year warranty.

Material: G90 coated steel and optional galvanized steel, aluminum, powder-coated. Ballast only.

How it maximizes energy density: SMS developed an Excel spreadsheet that determines the optimum row-to-row spacing based on the selected solar module, optimum tilt angle, solar azimuth angle, and the altitude angle all specific to install location. By optimizing the length of row-to-row spacers, the SMS system can greatly reduce the amount of redundant material, which in turn will reduce racking cost and avoid installing the modules in a high shadow region. The racks are designed with minimal distance between modules in the east/west direction to eliminate unused area.

Ecolibrium EcoFoot5D and EcoFoot2+

ecolibrium

EcoFoot5D 5-Degree and EcoFoot2+ 10-Degree speed installation and simplify logistics for flat-roof installs. Main components are: a base, pre-assembled clamps (integrated bonding without washers) and a wind deflector. The system is black, ASA-PC, UL Listed Resin with a 25-year warranty mounted with ballast, attachments or a mix.

How it maximizes energy density: EcoFoot5D 5-Degree delivers 18.4 percent more power than the 10-degree system and lowers cost per watt. The system maximizes roof density while maintaining the ease and simplicity of EcoFoot. The modular base is small at 7 in. x 16.7 in., and inter-row spacing is a dense 9.9 in., creating a tightly packed array. Stackable bases enable up to 290 kW per pallet, resulting in fewer pallets and minimized shipping, storage and onsite crane use.

— Solar Builder magazine

Degrees of Separation: How to mount commercial rooftop PV systems to maximize energy

Ecolibrium EcoFoot system

Ecolibrium EcoFoot system

On commercial rooftops, design trends are all about maximizing energy density. Module selection is a huge factor there, but so are the layout and tilt decisions — figuring out the perfect shape and tilt to mount as many modules as possible without compromising their performance.

Pairing the right racking system with a flat-roof space opens up a world of possible equations. Use a racking system that will position the panels to maximize the energy output, which includes the tilt angle, inter-row spacing and the direction the panels will face. As always, geography matters. For one, the roof’s azimuth, or the direction the pitch faces. For a perfect south-facing system, the azimuth should be 180.

But new systems are tweaking the traditional. East/west systems are becoming popular below the tropic of cancer. Designers are playing more with tilt angles, with the general trend moving toward 5-degree tilt — likely to reduce inter-row shading without compromising the number of modules used or resulting in too much soiling.

“Rooftop energy density is maximized by fitting more panels on the roof using a 5-degree racking system,” said Jonah Coles, product solutions manager, Ecolibrium Solar. “The key to fitting more panels on the roof is to use racking with a small footprint and narrow inter-row spacing. The combination packs in panels, yet the inter-row spacing is wide enough to allow for the working room needed for ease of installation and post-installation maintenance.”

RELATED: Why energy density matters — and three ways to maximize it

But the tilt decision isn’t one-size-fits all. Everest Solar Systems notes tilt angle efficiency correlates to latitude — the higher the latitude often requires a higher tilt. The latitude in Hawaii, for instance, allows a system to be virtually flat, but there needs to be enough tilt to keep the rain from pooling and to keep dust off the modules. Brandon Gwinner, regional sales manager, SunModo, puts that minimum at a 4-degree tilt.

SunModo Sunbeam

“The tilt degree is dependent on the region/location and optimum output based on TSRF,” he says. “The minimal tilt degree racking systems are typically to maximize the number of modules you can get on a roof without your rear post being 8 ft off the roof and to get the most energy density/power density per the project.”

There are also some wind/snow load considerations that can keep tilt below a certain height/tilt degree, as well as parapet walls and billowing of wind. The installer has to find the balance between production and engineering capabilities.

Also, installers looking to maximize production in summer months should consider using lower tilt angles than installers looking to maximize production in winter months. In snowy northern climates, Everest Solar recommends a 10-degree system tilt angle, which is better for shedding snow, plus the wider inter-row spacing allows more room for snow to land without piling up and casting a shadow or covering the modules.

“If you can hit your power goal with a 10-degree system, then 10-degree would be the system of choice. If not, 5-degree racking can enable a successful system when 10-degree wouldn’t fit enough panels to generate enough power,” Coles said.

Commercial installations have significantly more requirements than residential installations, so understanding jurisdictional requirements at the onset of the project will make the process go smoothly. Some states, like Oregon, do not require extra engineering when the tilt is under 18 in. on the back edge of the array, based on a prescriptive path. So, cost analysis vs. ease of permitting is a factor for tilt decisions too.

The inter-row spacing issue

Tilted PV panels cast shadows on the rows of modules behind them, necessitating a gap between rows to minimize the effects of production loss due to shadows cast on panels in anterior module rows. Here are a few ideas to mitigate the impact of this phenomenon on your PV installation via Peter Abou Chacra, engineering consultant, SunModo.

  • Reduce the tilt of your south-facing array. For peak energy production on a per-module basis, PV modules have an ideal incident angle with solar rays emanating from the sun. For some installations, however, it may make sense to reduce the tilt of the modules to a less optimal incident angle. Though this means less production on a per module-basis, it can mean a significant increase in the daily unshaded collection time for the array. This gain in effective collection time can offset the losses caused by a sub-optimal tilt for the module itself. Using software dedicated to modeling and analyzing a system’s performance at a different tilt angle and inter-row spacing should figure out the best path.
  • Locate your system on a south-facing slope. Even a five-degree inclination can have a marked impact on the amount of inter-row spacing required. This can significantly increase the number of modules you can fit in a given area.
  • Consider 3-in-landscape or 4-in-landscape monoslope installations. Coupled with a low tilt, this strategy can reduce inter-row spacing significantly on a given installation since modules on the same structure and slope don’t require significant spacing between them. This can be particularly effective if you can gradually elevate the anterior monoslope PV structures as you work your way north through the site.

— Solar Builder magazine