Module & Mounting Systems
PV Module Documentation
This article summarizes the critical information needed for design, SolarAPP+ permitting, and final inspection.
Contractors should also be prepared to provide this information to inspectors at the time of final inspection.
Important: the information below should be collected from the manufacturer’s installation instructions or the certifier’s certificates, and where noted below, should match the markings on the module label. Product datasheets may be helpful as a quick reference for designers but generally do not have all of the required information.
| Required information | Notes | Where located |
| PV module model # | A unique product identifier assigned by the manufacturer and referenced by the certifier. |
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| Safety Certifications | The standard(s) to which the product is certified. PV modules must be certified to UL 61730-1 and UL 61730-2 or UL 1703. AC modules must additionally be listed to UL 1741. BIPV modules may additionally be listed to UL 7103. |
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| Certification agency | The agency that certified the module. |
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| Fire Type Classification | The PV module and racking assembly must have a Fire Class (A, B, or C) that complies with local regulations. Most PV modules are assigned a numeric Fire Type (e.g. Fire Type 1, 2, 3, etc.) as part of the safety certification. This is not the same as an A, B, or C Fire Class.Modules with numeric Fire Type is certified as a Fire Class Rating (A, B or C) with the specific module Fire Type used in a roof-mounted system. See the help article on racking system for more information. Some PV modules, primarily those used in building-integrated PV systems, may be certified with a Fire Class Rating (A, B, or C), because they are tested as an assembly with a specific racking system. |
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| Temperature rating (maximum/minimum air temperature) | The PV module must be have a temperature rating that is compatible for the conditions of use. UL 61730-1 requires that modules are rated for use in an ambient temperature range of at least -40°C +40°C. UL 1703 requires that modules are rated for at least +40°C and that the minimum temperature rating is specified in the Module instruction manual. Modules may be rated for conditions beyond the minimum requirements of the standards if specified in the manufacturer’s instructions. |
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| Connector model | PV safety standards require that the connector model is specified in the instruction manual as well as the specific make/models (if any) that the connector is compatible with. It is important to use the same make and model for mated connections unless specific instructions in the manual allow other connector models to be used. |
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| Maximum system voltage rating (V) | The PV module must be rated for a voltage equal to or greater than the calculated maximum voltage of a module or string of modules at the lowest expected ambient temperature, as determined in accordance with NEC 690.7(A). |
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| Electrical ratings (monofacial modules) | Monofacial PV module power, voltage and current ratings at standard test conditions (STC, equal to 1000 W/m2 and 25°C) are be required to verify compatibility with connected equipment. The maximum short-circuit current under high irradiance conditions must be calculated in accordance with NEC 690.8(A). The maximum PV voltage at the lowest expected ambient temperature must be calculated in accordance with NEC 690.7(A). |
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| Electrical ratings (bifacial modules) | For bifacial modules, power and current levels increase depending on the amount of light that reaches the rear surface of the module and the modules bifaciality coefficients for power (φPmp) and current (φIsc). SolarAPP assumes power and current ratings for bifacial modules based on bifacial stress irradiance (BSI) in place of STC conditions. BSI assumes an exposure of 1000 W/m2 on the front of the module and 300 W/m2 on the rear side of the module. | For most modules[1]:
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| Power and voltage temperature coefficients | Temperature coefficients may be used to calculate the maximum expected voltage in accordance with NEC 690.7. |
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| Mechanical load rating (up/down)1 | Important notes: the combined wind, snow and gravity loads for a specific project cannot exceed the module’s design load rating specified in the manual for the specific mounting configuration used. The design load rating should not include the 1.5 x multiplier that is applied in the UL 61730-2 loading test. Modules that are mounted in a manner not specified in the module manual must be tested with the racking system and have an appropriate design load rating when assembled with the racking system. |
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| Module area (m2), length (m), width (m), weight (kg) | The module area, length, width and weight are important parameters as they affect the structural design of the system. |
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| Equipment compatibility with AC Modules | A listed AC module assembly must be compatible with connected equipment, including rapid shutdown or PV hazard control. Note: a PV module that is field assembled with a microinverter is not considered an AC module, as it is not listed as an assembly to UL 1741. |
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PV Racking System Documentation
This article summarizes the critical information needed for design, SolarAPP+ permitting, and final inspection.
Contractors should also be prepared to provide this information to inspectors at the time of final inspection.
Important: the information below should be collected from the manufacturer’s installation instructions or the certifier’s certificates, and where noted below, should match the markings on the racking or attachment labels. Product datasheets may be helpful as a quick reference for designers but generally do not have all of the required information.
| Required information | Notes | Where located |
| Racking manufacturer and model number | A unique product identifier assigned by the manufacturer and referenced by the certifier |
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| Certification agency | The agency (-ies) that certified the racking to UL 2703. A different agency may be used for each of the subject areas (bonding and grounding, fire rating, mechanical load). |
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| Racking safety certifications | Racking must be certified to UL 2703 with the specific PV model used, in all three critical subject areas: fire classification, design load rating, and bonding and grounding. Mounting systems labeled as being certified to UL 2703 are not necessarily evaluated for all three key subject areas with the specific PV model used. For more information: see below, and: https://www.seacgroup.org/s3-ul2703-information-bulletin. |
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| Bonding and grounding with specific PV modules | The PV model number is required to be included in the racking system manual specifically for the bonding and grounding certification to UL 2703. Note that the PV model numbers evaluated for bonding and grounding may be different than those evaluated for a design load rating or fire classification. |
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| System fire rating with specific PV modules | The PV module and mounting system assembly must have a Fire Class (A, B, or C) that complies with local regulations. The manual must indicate which PV module Fire Types (e.g. 1, 2, 3, etc.) have been evaluated with the racking system to achieve the Fire Class (A, B, or C). The manual must also indicate the permitted distances above the roof, and whether the racking system Fire Classification applies to a roof with a low slope (</= 2/12 pitch), steep slope (>2/12 pitch), or both. |
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| Design load ratings with specific PV modules | The combined wind, snow and gravity loads for a specific project cannot exceed the mounting system design load ratings specified in the manual. The design load rating should not include the 1.5 x multiplier that is applied in the UL 2703 loading test. Design load ratings for the upward, downward and lateral directions are required to be included in the racking manual. Modules that are mounted in a manner not specified in the module manual must be tested with the racking system to UL 2703 and verified to have an appropriate design load rating when assembled with the mounting system. The PV models certified with the racking system’s load rating are required to be in the racking manufacturer’s manual. |
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| Height above roof | To be eligible for SolarAPP, the maximum module height above the roof is 12”. In addition, it is important to verify that the standoff height complies with the manufacturer’s instructions, because the distance between the module and roof impacts structural loads and fire ratings.. |
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| Roof pitch | The roof pitch impacts the racking system’s structural loads and fire ratings. It is important to verify that the mounting system and module assembly have been qualified for “low slope” (</= 2/12” pitch) versus “steep slope” (>2/12” pitch) roofs. |
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| Racking tilt relative to roof plane | The tilt of the module and racking assembly impact both the structural loads and fire ratings. The mounting system and module tilt relative to the roof must comply with the installation instructions |
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| Racking system weight | The racking weight impacts the structural loads. |
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| Racking hardware | Racking systems must be installed with the hardware and procedure (such as torque, use of washers, etc.) specified in the manual, including the hardware used to secure and bond/ground the PV module frames. This hardware is typically shipped with the racking. However, the means of attachment to the roof may be sold separately (see below). |
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| PV module orientation | Modules may be installed in a “portrait” or “landscape” orientation. In a portrait orientation, the sides of the PV module with the longer dimension will be inclined relative to horizontal. In a landscape orientation, the sides of the PV module with the shorter dimension will be inclined relative to horizontal. |
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| Attachment manufacturer and model | Where permitted in the racking manufacturer’s instructions, the means of anchoring the racking to the roof may be achieved using a product made by a manufacturer other than the racking manufacturer. In such cases, documentation for the attachment assembly will be required. |
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| Attachment flashing / sealing certifications | Attachment systems are not required by code to be certified to a specific standard. However, some building officials may require confirmation that the method of sealing roof penetrations is adequate. This may be demonstrated by following the instructions of the roofing system manufacturer for sealing roof penetrations; utilizing a flashing or sealing system that is certified to UL 2703A; or other documentation at the discretion of the building official. |
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| Attachment configuration, hardware, installation method | The racking and/or attachment manuals must be adhered to regarding: permitted roof slope; roofing system materials and thicknesses; hardware, sealant and flashing specifications and installation process; requirements for roof deck or structural member material, type, grade, finish, and thicknesses; building attachments such as roof deck or structural members; staggering of attachment points; etc. See also “Maximum attachment spacings”. |
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| Maximum attachment spacings | The project’s largest distances between the racking system’s attachment points must comply with the racking and attachment system manufacturer’s instructions. The “X” distance between attachment points is defined as the distance perpendicular to the roof slope, and the ”Y” distance between attachment points is defined as the distance along the roof slope. The maximum allowable distance between attachment points is 72”. |
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| Maximum cantilever | If the end of any structural members of the racking system (such as rails) have a length that is unsupported, or “cantilevered” beyond the roof anchorage point, the cantilevered distance must comply with the racking manufacturer’s instructions. The maximum permitted cantilevered distance may be as small as 0” (no cantilever) or up to 72”. |
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| Additional project-specific information that affects the racking and attachment system design | SolarAPP publishes a “Structural Bulletin” with each permit package, which provides guidance on determining project-specific features that impact the structural design and installation of the system. These features include:
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[1] A February, 2023 Certifications Requirement Decision (CRD) to UL 61730-1 and UL 61730-2 requires that for bifacial module markings and documentation include bifaciality coefficients as well as power and current ratings at BSI. Module manufacturers may need to be contacted directly to determine bifaciality coefficients for modules evaluated prior to this date. Power and current at BSI can be derived from the ratings at STC and bifaciality coefficients for power and current according to the following equations:
Pmp (BSI) = Pmp (STC)*(1+0.3* φPmp)
Isc (BSI) = Isc (STC)*(1+0.3* φIsc)
[2] Labeling may be provided on the smallest unit packaging for racking components, and additionally it may be placed on racking components. Labeling is not required on individual parts.