Question
Can I use any UL Listed grounding lug evaluated to UL 467 for grounding a photovoltaic (PV) panel or supporting rack system? What devices are evaluated for grounding and bonding PV modules and mounting racks to comply with 2011 NEC Section 690.43(C), (D), and (E)?
Answer
No, UL certified (Listed) grounding and bonding devices are not automatically evaluated for grounding or bonding PV modules unless the Listed PV module or panel’s installation instructions identify that device as suitable for grounding or bonding its modules. Grounding and bonding lugs are evaluated for compliance with the Standard for Safety for Grounding and Bonding Equipment, UL 467, and are certified (Listed) under the product category Grounding and Bonding Equipment (KDER) located on page 224 in the 2013 UL White Book and online at www.ul.com/database by entering KDER at the category code search field.
The Guide Information for this product category indicates that grounding and bonding equipment intended for use in PV systems is additionally investigated in combination with the PV module/panel (see QIGU) to the applicable requirements for such products. Installation instructions provided with the PV system identify the specific grounding and bonding device that has been investigated and intended for use with that system. PV panels are certified (Listed) under the product category Photovoltaic Modules and Panels (QIGU) located on page 339 in the 2013 UL White Book and also online at www.ul.com/database and enter QIGU at the category code search.
Each PV panel or module and its frame and mounting systems is different, made of different materials and configurations so that a grounding or bonding device that has only been evaluated for compliance with UL 467 alone has not been evaluated for use in PV systems and doesn’t address the special conditions of grounding and bonding each uniquely constructed PV module frame to the wiring system and the module supporting racking systems. UL 467 alone doesn’t address the different weather conditions and conditions of mechanical loading such as the panels themselves and snow and wind loads that can affect the integrity and reliability of the grounding and bonding systems of PV systems over time.
Grounding and bonding devices as well as mounting and racking systems specifically evaluated for PV systems are UL certified (Listed) under the product category Mounting Systems, Mounting Devices, Clamping Devices and Ground Lugs for use with Photovoltaic Modules and Panels (QIMS) located on page 343 in the 2013 UL White Book and also online at www.ul.com/database and enter QIMS at the category code search field.
Products certified under the QIMS product category are evaluated for compliance with the Outline of Investigation for Rack Mounting Systems and Clamping Devices for Flat-Plate Photovoltaic Modules and Panels, UL Subject 2703. This category covers photovoltaic (PV) mounting systems, mounting devices, clamping devices (which may be for bonding and/or mechanical loading) and ground lugs intended for use with specific PV modules and panels and specified module frames and mounting structures as identified in the individual Listings. Both mounting systems and clamping devices may be investigated for mechanical mounting alone, or mechanical mounting and ground bonding as identified in the individual Listings. Ground lugs may be investigated for use with specific PV modules, specific PV module frames, or specific mounting-system rails.
The installation of these mounting systems, clamping devices or bonding devices is intended to be in accordance with ANSI/NFPA 70, National Electrical Code, in addition to any applicable building codes. Authorities having jurisdiction should be consulted as to conformance with applicable building codes, including the class of roof covering.
The devices certified under this category can be identified by the UL Listing Mark on the product that identifies it as one of the following product names: “Photovoltaic Mounting System,” “Photovoltaic Module Clamping Device,” “Photovoltaic Mounting Device,” “Photovoltaic Bonding Device,” “Photovoltaic Mounting and Bonding Device” or “Photovoltaic Ground Lug.” The word “photovoltaic” may be abbreviated “PV.”
The installation instructions will identify the panels, modules and racking systems as appropriate for which they have been certified. That information can also be found on UL’s Online Certification Directory at www.ul.com/database and enter QIMS at the category search field, then click on the specific manufacturer. The certification information will detail the specific installation criteria of what the devices are certified (Listed) for, as well as the products they are certified for use with.
