NEC 2017 Primer for Solar Installers: Manufacturers explain how their products meet the updated code

NEC 2017

Jan. 1, 2019, is almost upon us, which means the National Electric Code (NEC) 2017 is almost in effect. Not all jurisdictions will be up to speed (hell, some aren’t even up on NEC 2014 yet), but around 24 states will require compliance immediately. We asked a variety of manufacturers about their NEC 2017-ready products, how they work and any advice they have for solar installers to meet the new code.

This section is from our Nov/Dec issue of Solar Builder magazine. Subscribe for free right here.

Code to know

690.12 Rapid Shutdown of PV Systems on Buildings

PV system circuits installed on or in buildings shall include a rapid shutdown function to reduce shock hazard for emergency responders in accordance with 690.12(A) through (D).

(A) Controlled Conductors. Requirements for controlled conductors shall apply to PV circuits supplied by the PV system.

(B) Controlled Limits. The use of the term, array boundary, in this section is defined as 305 mm (1 ft) from the array in all directions. Controlled conductors outside the array boundary shall comply with 690.12(B)(1) and inside the array boundary shall comply with 690.12(B)(2).

1. Outside the Array Boundary. Controlled conductors located outside the boundary or more than 1 m (3 ft) from the point of entry inside a building shall be limited to not more than 30 volts within 30 seconds of rapid shutdown initiation. Voltage shall be measured between any two conductors and between any conductor and ground.

2. Inside the Array Boundary. The PV system shall comply with one of the following:

(1) The PV array shall be listed or field labeled as a rapid shutdown PV array. Such a PV array shall be installed and used in accordance with the instructions included with the rapid shutdown PV array listing and labeling or field labeling.

(2) Controlled conductors located inside the boundary or not more than 1 m (3 ft) from the point of penetration of the surface of the building shall be limited to not more than 80 volts within 30 seconds of rapid shutdown initiation. Voltage shall be measured between any two conductors and between any conductor and ground.

Know your signs

solaredge

SolarEdge’s SafeDC technology is embedded in its DC optimized solution and as such meets NEC 2017 without any additional components. The existing PV system AC disconnect is used as the initiator. Whenever the inverter or grid is turned off (i.e. AC power), then the DC voltage and current fall below the NEC 2017 thresholds within 30 seconds — each power optimizer is responsible for lowering its output voltage to 1 volt during rapid shutdown activation. This happens both in and outside the array boundary.

“New signs are required to inform emergency responders of the equipment meeting NEC 2017. NEC 2017 requires that equipment used as rapid shutdown devices be listed for rapid shutdown and evaluated according to stringent standards. Installers should check to ensure all equipment is properly listed. For example, inverters and combiners that are used inside or outside the array boundary as rapid shutdown devices must be listed for rapid shutdown in the event that they are used for that purpose,” says Lior Handelsman, founder, VP of marketing for SolarEdge.

HellermannTyton Don’t skimp on labels

HellermannTyton offers a line of NEC 2017 code compliant labels that have been tested to actual real-world conditions for over seven years and through accelerated aging tests, which show the labels will survive decades of exposure [see example of one that did not on the right]. Because of the extensive testing of these solar-compliant labels, HellermannTyton offers a seven-year warranty on all adhesive labels that include the HT check mark and a 25-year warranty on any aluminum labels.

“Many municipalities are very concerned about label life. In this age of OSHA and ANSI compliance, there is increased liability on installers and inspection services. If a label only remains visible for a few years, and if someone gets injured or killed in the process of interacting with the equipment, there can be substantial fines or costly litigation that can affect on-going business,” says Todd Fries, product category manager – identification for HellermannTyton.

Watch for SunSpec certification

sunspec

If you’re unfamiliar with the SunSpec Alliance, it’s time you became familiar. This trade alliance of more than 100 solar and storage stakeholders has been working on information standards for plug-and-play PV system interoperability, but its communication solution for meeting module-level power control and safety (rapid shutdown) with any panel and inverter combination might be its crowning achievement. Look for the logo to the left to find products certified to the SunSpec RSD Specification. Here’s a list of early adopter companies involved in the collaboration and rollout.

• ABB
• Adesto Technologies
• Canadian Solar
• Celestica Inc.
• Chint Power Systems –
North America
• Delta Products
• Enphase Energy
• ER Solar
• Fronius International
• Ginlong-Solis
• Hansol Technics Co.
• HiQ Solar
• Itek Energy
• Ingeteam
• JA Solar
• LERRI Solar Technology
• Maxim Integrated
• Mersen Electrical Power
• Midnite Solar
• Neo Solar Power
• Omron Global
• OutBack Power
• Phoenix Contact
• SMA
• Samil Power
• Seraphim Solar USA
• Semitech Semiconductor
• Silfab Solar
• Solartec
• ST Micro
• Sungrow
• SunPower
• Sunrun
• Sunpreme
• Suntech Power
• Talesun Tesla
• Texas Instruments
• Tigo Energy
• UL LLC
• Yaskawa Solectrica
• Yingli Solar

sunspec

This is a diagram of how the SunSpec Communication signal for module-level rapid shutdown works.

froniusCompliance doesn’t mean cost

“It is important to know what the actual requirement is and then getting to code compliance in the simplest, most cost-effective way to not put extra financial burden on the customer. We believe that industry standards and innovation will drive down cost and allow customer choice,” says Richard Baldinger, head of marketing for Fronius.

The Fronius Symo Advanced three-phase inverter combines the benefits of the Fronius Symo with the convenience of an open industry standard. Featuring 10 models ranging from 10 kW to 24 kW, the Fronius Symo Advanced meets NEC 2017 compliance in conjunction with the Tigo TS4-F cover via the integrated Power Line Communication (PLC) transmitter that uses the SunSpec communication signal for rapid shutdown. This eliminates the need for any additional communication hardware and provides the most cost-effective option for code compliance.

tigoTigo Energy’s TS4-F (Fire Safety) is a UL-certified multivendor rapid shutdown solution for commercial PV systems that complies with NEC 2017. The TS4-R-F is a simple add-on that retrofits a regular standard solar module with a module-level rapid shutdown device and is compatible with the power line-based SunSpec communication signal for rapid shutdown. Using the existing DC wires between the inverter and module-level electronics as a communication channel significantly reduces installation time.

midnite solarMidnite Solar’s MNLSOB line, in both 600-volt and 1,000-volt models, utilize one transmitter and multiple receivers per system. This product can be used for string or module-level shutdown by using one receiver per string or one per module. They plug directly into the MC4 connectors on your module and, because the MNLSOB transmitter induces a PLC signal into the PV Positive line, there is no additional or new wiring to be done between the transmitter and the receivers. Midnite Solar will be introducing a new SunSpec-compliant MNLSOB by January.

Make no compromises

“There are no additional design requirements to implement shutdown functionality. A designer can build a project for maximum energy harvest, optimal ROI, or with any other goal in mind and simply choose the most cost-effective MLPE to address his or her needs. The shutdown functionality is built into these solutions and does not impact other project considerations. Installers should also be aware of the upcoming release of UL Standard 3741 as another way to comply with NEC 201 690.12 without requiring module-level shutdown by using equipment listed as ‘PV Hazard Control Arrays,’” says Brad Dore, director of marketing for SMA America.

SMA’s Sunny Tripower CORE1 meets the shutdown requirements of NEC 690.12 when paired with a TS4-R-F module-level device. The inverter and MLPE retrofit unit operate on the new SunSpec Power Line Communication (PLC) signal for module-level rapid shutdown. This solution is the most cost-effective way to achieve module-level shutdown. The solution operates on a simple “stay alive” signal broadcast from the inverter over the existing DC wires. The TS4-R-F units will operate while AC power is present, and if AC power is cut via the AC disconnect, the MLPEs lose the “stay alive” signal and de-energize in accordance with code.

Streamline to ground

Section 690.43 states that “Exposed noncurrent-carrying metal parts of PV module frames, electrical equipment, and conductor enclosures of PV systems shall be grounded in accordance with 250.134 or 250.136(A), regardless of voltage.”

brilliant rack

Brilliant Rack racking systems feature mounting connections with serrated bolts that ensure the most effective metal-to-metal contact for proper bonding connections. These connections are essential for dispersing any electrical charge, providing multiple pathways to soil in compliance with Section 250.92 B. This reduces the danger of equipment damage or human injury should the rack become electrically charged through equipment malfunction, human error or lightning strike. Independent testing has demonstrated Brilliant Rack systems are capable of dispersing higher currents through the system into soil, and that the serrated bolt and nut are likely to maintain this connection better over a long period of time than WEEB clips.

sunmodo

SunModo’s ground lug, self-bonding clamps and self-bonding rail splices meet the requirements found in NEC 2017. The basis of the self-bonding system is its patented stainless-steel floating bonding pin, which is designed to be captive in the mounting components and provides a bonding path from the PV panel frames to the rails and rail splices and finally to the ground lug. The Ground Lug is compliant with both UL 467 and the equipment grounding requirements 690.43. The self-bonding system is for use with PV modules that have a maximum series fuse rating of 30A.

 

 

Rooftop Adder Table removed

quick mount pv

“The Rooftop Adder Table that has affected the ampacity calculations for conductors that are run at a specified distance above a rooftop has been deleted. This table generally hasn’t been well accepted by electrical personnel since its addition to the NEC several years ago. Because of the deletion, if raceways are kept at least 7/8 of an inch above the rooftop, there should no longer be a need for upsizing conductors and increasing costs,” says Randy Barnett, safety compliance professional for the NFPA.

Quick Mount PV has two NEC 2017-ready products in its classic conduit mount and conduit mount for tile. When used in conjunction with a standard off-the-shelf conduit hanger, the conduit is raised in excess of the minimum 7/8-in. off the roof surface, which is new in NEC 2017. These mounts are designed to lift electrical conduit off the roof to protect wiring from overheating. These mounts use Quick Mount’s proprietary waterproofing technology to seal the roof penetrations, and aluminum and stainless steel parts are used to secure the electrical conduit for the life of the system.

— Solar Builder magazine

Streamlined residential solar: Solaria, Enphase Energy, Quick Mount PV join forces

Solaria Power XT Enphase AC module

Solaria Corporation, a global provider of high efficiency solar modules, is teaming with mounting and racking provider Quick Mount and microinverter manufacturer Enphase Energy, to produce a single, unified system that ensures efficiency, performance and aesthetics. Available through select distributors, the complete solution gives solar installers the ability to streamline installation and ensure homeowner satisfaction at the lowest possible cost.

Solaria manufactures the PowerXT pure black solar modules using advanced cell interconnect and module production processes, significantly boosting power generation and providing outstanding performance with unmatched aesthetic appeal.

Quick Mount PV’s QRail racking system features patented QClick and QSplice technologies that simplify and speed solar installation. The result is the fastest and most reliable system deployment in solar.

The Enphase IQ 7+ Microinverter features Enphase’s two-wire cabling for ease of installation, and leverages semiconductor integration for higher reliability and better economies of scale. The 295 W AC Enphase IQ 7+ Micro combines efficiency, reliability and streamlined installation and is available either as a standalone component or in the factory-integrated Enphase Energized PowerXT-AC module from Solaria, which further improves installation efficiency.

Solaria will be exhibiting at booth 1251 at Solar Power International in Anaheim, September 25-27, 2018.

— Solar Builder magazine

Keep it simple, solar: Advice and products to streamline your next rooftop install

Keep part counts low

solar roof hook

The Low Profile QuickBOLT with Microflashing from SolarRoofHook can be installed in less than 60 seconds, and the key is its Microflashing technology, which is installed on top of the shingles and eliminates the need to pry apart shingles and shove oversized aluminum flashing underneath.

“We would like to see installers move away from the old-school aluminum flashing method and replace that with Microflashing technology,” said Samantha Dalton, marketing manager for SolarRoofHook. “Using Microflashing reduces installers risk too. When installers are forced to separate shingles to install aluminum flashing, they often must remove nails from the roof. This leaves open penetrations in the roof, as well as leads them to risk voiding the roofing warranty and breaking code. Microflashing doesn’t pose those same risks and bonds with the roofing material to create a watertight seal.”

Quick Mount debuts new full rooftop rail system

 Quick Mount QRail

Quick Mount PV is simplifying your supply chain with QRail, its new rooftop racking system featuring patented QClick and QSplice technologies that simplify and speed installation. QRail combines with Quick Mount PV’s waterproof mounts to create a complete, fully-integrated racking and mounting solution for installing solar PV modules on any roof.

The patented QClick technology enables module clamps to easily click into the rail channel and remain in an upright position, ready to accept the module. QRail’s QSplice is the fastest, most efficient splice in the industry — a tool-free, bonded, fully-structural splice that installs in seconds with no extra hardware required.
Electrical bonding is fully integrated into every system component. All electrical bonds are created when the components are installed and tightened down. QRail is fully code compliant, certified to UL 2703, and backed by a 25-year warranty.

Pre-assembly

Magerack,

As a best practice, Jason Xie, president of Magerack, recommends assembling components on the ground as much as possible and avoiding assembling tiny components such as rubber washers on the roof.

For example, Magerack solar mounting components don’t contain any rubber components and all components are pre-assembled out of box. Magerack roof attachment doesn’t need any rubber washer and has no tiny components except pre-assembled fasteners. The two major components of MageMount MageMount II Rail-less Solar Mounting System, module connector and module brackets, can be assembled to the solar module on the ground before moving them on the roof. Module connectors are used to connect and secure two adjacent solar modules along the same row or between two rows. Those connectors and the roof attachments can be attached anywhere along the module edge where they are needed the most.

Look to kits

Unirac’s SunFrame Microrail

Consider systems where only a single tool is required for installation. Take Unirac’s SunFrame Microrail or the new Pro Series SM for example. Parts come pre-assembled out of the box making for a quick and easy install on the roof. There is no need to fumble with loose parts and pieces. Parts can be pulled from the box and can be put straight to use.

“One tool installation saves time on the roof, eliminating the chance of dropping tools while changing sockets,” says Anthony Romero, lead trainer for Unirac.

The SM Pro Series features module agnostic mid and end clamps. The end clamps secure the module while staying beneath the module. Arrays look very clean and appealing without any rail or hardware protruding. The mid clamps come pre-assembled and are self-standing. They also come coated with anti-seize to prevent galling and breaking stainless steel bolts. Unirac’s FlashKit Pro comes in a pack of 10 with flashing, L-Feet, T-bolts and lag bolts in one convenient box. Having everything in one package helps cut down on the amount of packaging needed on the roof. They are the easiest flashing kit to count, kit and carry to the roof.

SKU reduction

SunRunner 4 clip

The SunRunner 4 clip from Heyco was developed to reduce the number of SKUs for an installer. For those using a mix of SolarEdge and Enphase, this clip will handle both types of cable. The SunRunner 4 clips directly onto the PV module frame and holds up to four SolarEdge cables or up to three Enphase Q cables comfortably. The SunRunner 4 takes the guesswork out of ordering the correct clip as it holds both types of cable. Heyco also manufactures top rail clips with the exact same clip design as its SunRunner 4 for top racking manufacturers like Unirac, IronRidge, and Everest. This universal design allows the clips to be used on a wider range of installations and reduce the number of SKUs (and headaches) for installers. Heyco also offers a series of nylon UVX clips which qualify for its 20-year warranty and are generally 20 percent less expensive than their stainless steel equivalents.

— Solar Builder magazine

Florida’s 3D Solar installs first Quick Mount QRail Racking System

QRail Quick Mount

Quick Mount’s QRail

3D Solar, a Florida-based solar contractor, and Quick Mount PV, a manufacturer of waterproof mounting and racking systems, announced today that 3D Solar has installed the nation’s first Quick Mount PV QRail Racking System. QRail is an innovative new rooftop racking system, with patented QClick and QSplice technologies that simplify and speed up installation. QRail combines with Quick Mount PV’s renowned waterproof mounts to create a complete, fully-integrated racking and mounting solution for installing solar PV modules on any roof.

3D Solar is so confident in the flashing system that it has decided to offer Florida’s best solar rooftop installation warranty of 25 years.

“Our installers have told us that this system makes the installation process easier, faster and more efficient,” said 3D Solar Owner and CEO David Ringo. “QRail enables us to better serve our customers, providing them with the best waterproof solar mounting systems in the industry. Quick Mount PV products are a great fit with our approach to solar: going above and beyond to ensure every job is completed to our highest standards.”

The patented QClick technology enables module clamps to easily click into the rail channel and remain in an upright position, ready to accept the module. QRail’s QSplice is the fastest, most efficient splice in the industry — a tool free, bonded, fully-structural splice that installs in seconds with no tools or extra hardware required. Read more about the system here.

“We’re thrilled that 3D Solar is installing solar rooftop arrays with our new QRail racking system,” said Quick Mount PV CEO Claudia Wentworth. “With QRail, we now have what our customers have been requesting: a comprehensive, cost-effective single-source solution for solar installation on all roof types. And because of the QClick and QSplice technologies, solar installers will find that QRail exceeds their expectations for quality and ease of installation.”

Download our free 2018 Residential Rooftop Report for more tips and install trends

— Solar Builder magazine

The Replacements: These solar mounts for tile rooftops cut labor costs, avoid OSHA issues

Quick Mount PV’s Tile Replacement Mount

It’s always reassuring when solar technology moves faster than a federal regulator, even if it is a well-intentioned agency like the U.S. Labor Department’s Occupational Safety and Health Administration (OSHA). In this recent case, a new crop of solar tile replacements that support rooftop mounting systems are eliminating the need for drilling, grinding or sawing cement tiles, an activity that generates harmful dust for workers when not controlled carefully.

Stuck in the Middle

OSHA came down with a new silica rule (29 CFR 1926.55, 1910.1000) in October that limits worker exposure to 50 micrograms of silica dust per cubic meter of air over an eight-hour time-weighted average. Penny-wise-and-pound-foolish solar companies that still choose the cheapest tile hooks requiring them to saw or drill cement tiles now must monitor worker exposure to silica dust and mitigate exposure through practices including mask use, wet-cutting and dust collection. Other more forward-looking solar companies will simply opt for the new tech and cut their BOS labor costs for a net job gain.

Sawing or drilling concrete roof tiles was the standard for installing rooftop PV mounting systems up until a few years ago. Now a number of tile replacement manufacturers say that their products are no more costly than most old-design tile hooks, are faster to install and save a roof tile at every penetration point. Saving tiles for an older roof is no small event. Cement tile costs around $7 per square foot, when a replacement with the same shape can be found, much less with matching fade.

“I’m not sure how much the new OSHA rules will drive the tile replacement mounting market or affect it, because the market will change more as companies see the benefits of saving time and cost,” reckons Andrew Wickham, the marketing manager for SnapNrack Solar Mounting Solutions.

SnapNrack’s tile replacement

SnapNrack’s tile replacements feature a base assembly for simply lagging the base into place and then sliding the riser shaft into position for the tile replacement flashing.

Color Me Impressed

Several replacement tile mount manufacturers suggest that their cement tile replacement product goes on faster than tile sawing or drilling.

“We are a bit more expensive than hooks, but there is far less labor,” says Jordan Pacheco, the director of product management at Pegasus Solar. “An installer that is grinding tiles might use four crews of five men, but we can do five crews of four men with our Lightspeed Tile Replacement.”

The U.S. market for rail-less residential solar mounting systems, the Pegasus specialty, is expected to grow by 67 percent from $240 million in 2016 to $400 million by 2022, according to GTM Research. The Pegasus tile replacement system, available in rail or rail-less mounting configurations, has undergone several refinements in design since it initially launched in 2014.

“The tile replacement technology is definitely faster, and some studies say 20 percent faster than grinding,” says Stri Zulch, the vice president of marketing at Quick Mount PV.

In a time trial in 2016, Quick Mount conducted an in-house test with three different products. The trials were conducted on a test roof, with eight mounts installed for each trial. The installers were third-party contractors, and Quick Mount PV timed and monitored the trials.

“Results showed that the Tile Replacement Mount was 26 percent faster than the Universal Tile Mount and 22 percent faster than Quick Hook,” the company reports. “The Tile Replacement Mount eliminates the need to cut tiles, resulting in the Tile Replacement Mount saving time. Although, there are a number of variables that affect installation times, the Tile Replacement Mount will save on average a minute per mount.”

Quick Mount PV’s Tile Replacement Mount

Quick Mount PV’s Tile Replacement Mounts feature its patented Elevated Water Seal Technology for optimal waterproofing

Quick Mount’s Tile Replacement Mount comes with a 25-year warranty and features a universal base mount, which works with three flashing profiles including a flat tile, S-shaped tiles and W-shaped curved tiles.

“Once you see more of these large-scale installs, it will drive the market for tile replacements,” says Brandon Gwinner, the western region sales manager for SunModo. One of his customers using SunModo’s tile replacement on a large cement tile project in Hawaii with 2,800 support points, reports cutting project labor costs in half — with no tile breakage.

The SunModo tile replacement can be attached either by a single bolt into a rafter, like most tile replacement designs, or by four screws into the sheathing, in cases where a rafter is not reachable. The industry is now trending toward the sheathing-attached method since it is more reliable and is now proven, Gwinner notes. While his company specifies no less than 1/2-in. oriented strand board (OSB) sheathing, many home builders or roofers opting for cement tiles are upgrading the sheathing by using thicker OSB, if not structural-grade 5-ply plywood, he notes.

Here Comes a Regular

After the construction downturn resulting from the recession in 2008, roofing is on an upturn and expected to reach a global value of $95 billion by 2024, according to a September report by Global Industry Analysts.

Cement tile is the fastest growing segment of the global roofing market, with an estimated combined average growth rate of close to 7 percent by 2020, according to a recent study by Technavio. Recent hurricanes and other adverse weather have helped demonstrate the durability of cement tiles over asphalt shingles and over clay tiles, which are much lighter than cement tiles.

In the U.S. South and Southwest, where daily temperature highs and lows range widely, and air conditioning is a major use of electricity, cement tiles are a favorite because they can be used for cool roofs as well as for evening heat retention.

Tile replacements for cement tiles already are highly waterproof and manufactured with formable aluminum. But cement tiles also are evolving via nanotechnology. Nanotech coatings for cement tiles will provide additional benefits for protection against heat, mold, mildew, fungus and algae, according to Global Industry Analysts.

Overall, signs indicate that the U.S. adoption rate for tile replacements should accelerate. However, at the heart of the market is installer awareness and preference. “For the market to grow, installers will need more education about the advantages of tile replacements,” suggests Stella Sun, the marketing director for SunModo.

Charles Thurston is a freelance writer covering solar energy from Northern California. He is not to blame for all of the Replacements song references.

— Solar Builder magazine