Patent Publication Number: US-2016233822-A1

Title: Photovoltaic grounding system and method of making same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is a divisional of and claims priority to U.S. Non-Provisional application Ser. No. 14/026,853, filed Sep. 13, 2013, which is a continuation-in-part of and claims priority to U.S. Non-Provisional application Ser. No. 13/079,900, filed Apr. 5, 2011, the disclosures of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Embodiments of the invention relate generally to photovoltaic (PV) systems and more particularly to a system and method for grounding a PV system. 
     PV systems include PV modules arranged in arrays that generate direct current (DC) power, with the level of DC current being dependent on solar irradiation and the level of DC voltage dependent on temperature. Typical PV systems include modules with metal frames and metal mounting racks that are in exposed locations such as rooftops where they are subject to lightning strikes, or are located near high voltage transmission lines that may come into contact with components of the PV system in the event of high winds, etc. The metal frames of the PV modules are typically made of an anodized aluminum to protect the frames from exposure to the elements. To mitigate the impacts of line surges or unintentional contact with high voltage lines, the metal components of PV systems are grounded to create a lower impedance path to ground so that, in the case of any system component that is shorted to the metal frame or rail, the short circuit current will be shunted to ground through the ground circuit path rather than through a person working on the PV system. 
     To meet the national electrical code (NEC), special DC wiring and grounding specifications must be met for DC module strings capable of producing voltages as high as 600 volts. A failure in the insulating material of the PV laminate could allow the frame to be energized up to 600V DC. To satisfy existing electrical codes and standards, the frame of each PV module is typically grounded using a heavy (e.g., #8 gauge) copper wire and a 10-32 screw that can cut into the frame. For module frames with anodized surfaces, additional components, such as washers/connectors (sometimes called “weebs”) are used to penetrate into the metal frame and provide a reliable electrical contact. These weebs are installed between adjacent PV module frames on-site and operate to create a direct electrical connection between adjacent PV modules. In a separate installation step, grounding wires are used to connect the metal case of the micro-inverter of each module to the respective module frame. 
     Because the aluminum frames of modules in a PV array are typically anodized, grounding the frames does not ensure that the metal mounting racks or rails of the PV system are grounded. Thus, PV systems include additional heavy wire ground leads (e.g., #8 gauge copper wire) that are attached to each separate rail section at the installation site and brought to a common point. All other metal components of the mounting system are also individually grounded to the system ground by dedicated ground connections. Because all of these ground connections are made on-site by an installer who has specialized training in solar installations, the process for grounding the PV system accounts for 25-30 percent of the time and cost of the overall installation of the PV system. 
     Therefore, it would be desirable to provide a PV system with simplified ground connections for the metal components of the PV system that meets NEC standards and reduces the time and cost of on-site installation of the PV system. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In accordance with one aspect of the invention, a photovoltaic (PV) grounding system includes a first grounding path comprising an electrical connection between a plurality of support bars of a rail system and a connection box coupled to the rail system. The PV grounding system also includes a second grounding path comprising an electrical connection between the connection box and a plurality of PV modules disposed within the rail system, the second ground path extending from micro-inverter ground leads of the plurality of PV modules, through an extension harness electrically connected to the plurality of PV modules, to a ground connection within the connection box. The PV grounding system further includes a third grounding path that includes an electrical connection between the ground connection within the connection box and a building load panel. The first grounding path, the second grounding path, and the third grounding path are electrically connected within the connection box. 
     In accordance with another aspect of the invention, a method of manufacturing a photovoltaic (PV) grounding system includes providing a first PV panel having a frame, electrically coupling a metal housing to the frame of the first PV panel, the metal housing having a micro-inverter disposed therein, and coupling a first end of a micro-inverter ground lead to the metal housing. The method also includes assembling a plurality of support bars to form an equipotential rail system, positioning the first PV panel within the rail system, and coupling a second end of the micro-inverter ground lead to an extension harness, the extension harness including a plurality of connection modules electrically coupled to an extension ground lead of the extension harness. The method further includes coupling a connector box to the rail system such that the connector box is at equipotential with the rail system, positioning a first end of the extension harness within the connector box, positioning a load ground lead of a load panel within the connector box, and coupling the load ground lead to the extension ground lead within the connector box. 
     In accordance with yet another aspect of the invention, a photovoltaic (PV) system includes an equipotential rail system and a first PV circuit. The first PV circuit includes a first multi-module wiring harness disposed within the rail system, a first plurality of PV modules disposed within the rail system, each of the first plurality of PV modules having an internal ground lead electrically coupled to the first wiring harness, and a first connection box mechanically and electrically coupled to the rail system and a ground lead wire of the first wiring harness. The PV system further includes a first home run cable comprising a first end and a second end, the first end mechanically and electrically coupled to the first connection box, and the second end coupled to a ground connection of a circuit breaker panel. 
     These and other advantages and features will be more readily understood from the following detailed description of preferred embodiments of the invention that is provided in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate embodiments presently contemplated for carrying out the invention. 
       In the drawings: 
         FIG. 1  is a front perspective view of a photovoltaic (PV) system, according to an embodiment of the invention. 
         FIG. 2A  is an exploded perspective view of a portion of the PV system illustrated in  FIG. 1 , according to an embodiment of the invention. 
         FIG. 2B  is an enlarged view of portion  2 B in  FIG. 2A  showing a connector of an extension harness of the PV system. 
         FIG. 3A  is a rear schematic view of a PV module useable with the PV system shown in  FIG. 1 , according to an embodiment of the invention. 
         FIG. 3B  is an enlarged view of portion  3 B in  FIG. 3A  showing lead wires within a wiring harness of the PV module. 
         FIG. 4  is a schematic diagram of a common connector box of  FIG. 4  useable with the PV system of  FIG. 1 , according to an embodiment of the invention. 
         FIG. 5  is a schematic diagram illustrating a grounding path of the components of the PV system of  FIG. 1 , according to an embodiment of the invention. 
         FIG. 6  is a schematic diagram of a multi-circuit PV system, according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention provide for a simplified system for grounding a photovoltaic (PV) system. 
     Referring now to  FIG. 1 , a photovoltaic (PV) system  10  is illustrated according to an embodiment of the invention. PV system  10  includes a pair of basic building block assemblies  12 ,  14  and a rail system  16  that includes a number of support bars, as described in detail below. In the embodiment shown in  FIG. 1 , each basic building block assembly  12 ,  14  of a photovoltaic (PV) mounting system  10  includes a row of five (5) PV modules  18 . However, one skilled it the art will appreciate that embodiments of the invention are not limited to a basic building block assembly having a particular number of PV modules  18 . Thus, according to alternative embodiments, basic building block assemblies  12 ,  14  may include any desirable number of PV modules  18  depending on design specifications and applicable limitations imposed by the National Electrical Code (NEC). 
     Rail system  16  of PV system  10  has an asymmetric design that allows n rows of PV modules  18  to be supported by n+1 horizontal rail sections. For example, a PV system having two (2) rows of PV modules would be supported by three (3) rail sections. In one embodiment, rail system  16  includes five (5) support bars including a top metallic rail section  20 , a central metallic rail section  22 , a bottom metallic rail section  24 , a first grounding bar  26 , and a second grounding bar  28 . As shown in  FIG. 1 , first and second grounding bars or support bars  26 ,  28  are positioned in a perpendicular arrangement to rail sections  20 ,  22 ,  24 . Fastener assemblies  30  mechanically and electrically couple first and second grounding bars  26 ,  28  to respective ends of rail sections  20 ,  22 ,  24 , as described in additional detail below. L-brackets  32  mount metallic rail sections  20  to mounting stanchions  34 . 
     According to one embodiment, top, central, and bottom rail sections  20 ,  22 ,  24  and first and second grounding bars  26 ,  28  are constructed of an anodized metal, such as, for example, aluminum. In such an embodiment, fastener assemblies  30  include self-tapping screws or components constructed to break through the anodized surface of grounding bars  26 ,  28  during the assembly process in order to create an electrical connection between the base metal of grounding bars  26 ,  28  and the base metal of rail sections  20 ,  22 ,  24 . First and second grounding bars  26 ,  28  thus act to electrically bond together top, central, and bottom rail sections  20 ,  22 ,  24 . Because rail sections  20 ,  22 ,  24  and grounding bars  26 ,  28  are electrically coupled together at a low resistance, the components within rail system  16  are at the same electric potential. In other words, the components within rail system  16  are at equipotential. 
     According to one embodiment, first and second grounding bars  26 ,  28  and top, central, and bottom rail sections  20 ,  22 ,  24  include predrilled holes for fastener assemblies  30  to ensure correct physical spacing between rail sections  20 ,  22 ,  24  and reduce installation errors. 
     An exploded perspective view of a portion of PV system  10  associated with basic building block assembly  14  is illustrated in  FIG. 2A . In one embodiment, fastener assemblies  30  include respective pairs of fasteners  36  and star washers  38  that mechanically and electrically couple first and second grounding bars  26 ,  28  to top metallic rail section  20  and bottom metallic rail section  24 . 
     A locking cover assembly  40  is mounted to central metallic rail section  22  for holding PV modules  18  in place. In one embodiment, locking cover assembly  40  includes an individual locking cover for each PV module  18 , which allows an individual PV module  18  to be removed for maintenance. Locking cover assembly  40  is attached to central metallic rail section  22  with fasteners that penetrate the anodized surfaces of rail section  22  and locking cover assembly  40  during installation to create a grounded connection between rail section  22  and locking cover assembly  40 . Central metallic rail section  22  also includes a multi-module AC extension harness  42 , which is secured to central metallic rail section  22  using known fasteners such as, for example, clips (not shown). According to one embodiment AC extension harness  42  includes a pair of AC lead wires  44 ,  46 , a neutral lead wire  48 , and an extension ground lead wire  50 . In one embodiment AC lead wires  44 ,  46  are 120 volt AC leads. A number of slotted connectors  52  are positioned along the length of AC extension harness  42  to interface with respective PV modules  18 , as described in more detail with respect to  FIGS. 3A and 3B . Each connector  52  includes four slots  54 ,  56 ,  58 ,  60 , one for each respective lead wire of extension harness  42  as shown in  FIG. 3B . While extension harness  42  and locking cover  40  are illustrated as being associated with central metallic rail section  22 , extension harness  42  and locking cover  40  may, alternatively, be positioned within top or bottom metallic rail sections  20 ,  24 , and/or travel along multiple sections of rail system rail system  16 , including first and second grounding bars  26 ,  28 , based on design specifications. 
       FIG. 3A  is a schematic view of the rear or back side of an exemplary PV module  18  of PV system  10 . According to one embodiment, each PV module  18  is an AC module that includes a low voltage DC module  62  and an integral DC-AC micro-inverter  64  disposed within a metallic housing  66 . DC module  62  is coupled to micro-inverter  64  by a set of DC leads  68 . In one example, PV module  18  is constructed to produce 240 volts of AC power. In other examples, PV module  18  may be constructed to produce 120 volts of AC power or three phase 208 volt AC power. According to various embodiments, PV module  18  is constructed to have a maximum DC voltage less than the UL safety limit of 48 volts DC, such as, for example, 30 volts. 
     Each PV module  18  includes a metallic frame  70  to which the metallic housing  66  of micro-inverter  64  is attached. While  FIG. 3A  illustrates housing  66  attached to one of the longer, vertical sides of frame  70 , one skilled in the art will recognize that housing  66  may be attached to one of the shorter, horizontal sides of frame  70  and at alternative locations along the length of frame  70  based on design specifications. 
     In one embodiment, metallic housing  66  is mechanically and electrically attached to metallic frame  70  of its corresponding PV module  18  by a metallic frame attachment bracket  72  using a connector assembly  74  that includes a bolt  76 , a star washer  78 , and a locking nut (not shown). When connector assembly  74  is tightened, star washer  78  cuts through the anodization of metallic frame  70  and creates an electrical bond between metallic housing  66  of micro-inverter  64  and metallic frame  70 . A second connector assembly  80  locks metallic housing  66  in position on metallic frame  70 . According to various embodiments, second connector assembly  80  may be a fastener similar to connector assembly  74  or a self tapping screw. In alternative embodiments, metallic housing  66  is directly coupled to frame  70  absent a metallic frame attachment bracket. 
     PV module  18  includes an AC module wiring harness  82  coupled to the output of micro-inverter  64 . AC wiring harness  82  includes four lead wires: two (2) AC lead wires  84 ,  86 , a neutral lead wire  88 , and a micro-inverter ground lead wire  90  as shown in  FIG. 3B . In an embodiment where PV module  18  has a 240 volt AC output, AC lead wires  84 ,  86  are 120 volt AC leads. A first end  92  of ground lead wire  90  is connected to a ground lug  94  inside metallic housing  66 . Ground lead wire  90  is electrically connected to metallic frame  70  through the connection between metallic frame attachment bracket  72  and metallic frame  70 . AC module wiring harness  82  thus provides ground continuity. Also, if micro-inverter  64  of PV module  18  is unplugged from extension harness  52 , the overall system ground connection remains intact. Therefore, ground lead wire  90  in AC module wiring harness  82  is electrically connected to metallic frame  70  in a manner that meets NEC specifications. 
     AC module wiring harness  82  includes a connector  96  constructed to interface with AC module wiring harness  82 . Connector  96  may be mounted onto frame  70  or hang loose from PV module  18 , according to various embodiments. In one embodiment connector  96  is a “plug and play” connector having a pair of AC voltage pins  98 ,  100 , a neutral pin  102 , and a DC ground conductor pin  104  that correspond with the respective lead wires  84 - 90  of AC module wiring harness  82 . For example, a second end  106  of ground lead wire  90  is coupled to ground conductor pin  104 . Plug and play connector  96  is constructed to interface with respective slots  54 - 60  of plug and play connector  52  of AC extension harness  42  ( FIG. 2 ) that receive pins  98 - 104 . As used herein “plug and play” connectors refer to connectors that include wire terminations in the form of one of pins or slots, with a female plug and play connector having slots and a male plug and play connector having pins. Connection between the female and male plug and play connectors is made by plugging the two components together, thereby permitting a quick, reliable connection without hand-wiring the individual lead wires of two wire harnesses together. While connector  96  of AC module wiring harness  82  is described herein as including pins  98 - 104  and extension harness  42  is described as including attachment slot  108 , the pins and slots can be located on either connector  96  or extension harness  42 . 
     While rail system  16  acts to mechanically hold PV modules  18  in position, the physical contact between rail system  16  and PV modules  18  does not create an electrical connection between rail system  16  and PV modules  18  due to the anodized surfaces of the metallic frame  70  PV modules  18  and top, central, and bottom rail sections  20 ,  22 ,  24 . As such rail system  16  is not automatically connected to the ground lead wire  90  in AC module wiring harness  82  or the ground lead wire  50  of extension harness  42 . The ground connection is instead made in a switch connector box  110  mounted to rail system  16 . 
     In an exemplary embodiment, switch connector box  110  is mounted to top metallic rail section  20 , as shown in  FIG. 1 . Alternatively, switch connector box  110  may be mounted to one of the other rail sections  22 ,  24  or one of the grounding bars  26 ,  28 . As one skilled in the art will recognize, the location of switch connector box  110  may be determined based on design specifications. 
       FIG. 4  illustrates a schematic view of switch connector box  110 , which may be a constructed of a metal or non-metal material according to various embodiments. In embodiments where switch connector box  110  is metallic, switch connector box  110  is coupled to rail system  16  ( FIG. 1 ) using a fastener assembly  112 , similar to fastener assemblies  30  ( FIG. 2 ), that includes a star washer  114  that penetrates the anodized surface of rail system  16 , thereby forming an electrical connection between a ground lug  116  coupled to an inside surface of switch connector box  110  and rail system  16 . In embodiments where switch connector box  110  is non-metallic, ground lug  116  is electrically coupled to rail system  16  using an optional wired connection  118  (shown in phantom) between ground lug  116  and rail system  16 . 
       FIG. 4  illustrates the wiring connections made within switch connector box  110  between lead wires  44 ,  46 ,  48 ,  50  of extension harness  42  and corresponding AC lead wires  120 ,  122 , a neutral lead wire  124 , and a ground lead wire  126  of a home run cable  128 , which feeds the electrical current from PV modules  18  of basic building block assemblies  12 ,  14  to a building load panel, such as, for example, a conventional 15 amp circuit breaker panel. To make the connections, a first end  130  of extension harness  42  and a first end  132  of home run cable  128  are fed into switch connector box  110 . As shown, ground lead wire  50  of extension harness  42  and ground lead wire  126  of home run cable  128  are spliced and electrically connected to a ground lug  116  that is coupled to an inside surface of switch connector box  110 , thereby completing the ground connection between rail system  16  and extension harness  42 , and by extension, the ground connection with metal components of PV modules  18 . According to one embodiment, extension harness  42  includes AWG 12  wire and the home run cable  128  includes AWG 10  wire for AC lead wires  120 ,  122  and AWG 8  wire for ground lead wire  126 . 
       FIG. 5  illustrates the grounding paths of PV system  10 , which includes a home run grounding path  134 , a rail system grounding path  136  for first and second grounding bars  26 ,  28  and rail sections  20 ,  22 ,  24 , and an electronics grounding path  138  for micro-inverters  64  of PV modules  18 . 
     Home run grounding path  134  is formed through an electrical connection between a building load panel or circuit breaker panel  140  and switch connector box  110 . Rail system grounding path  136  is formed by the electrical connection between switch connector box  110  and the support bars of rail system  16  (i.e., first and second grounding bars  26 ,  28  and rail sections  20 ,  22 ,  24 ). As such, rail system grounding path  136  travels through all of the metal components of rail system  16 . Since rail system  16  is at equipotential and rail system grounding path  136  travels through all of the metal components of rail system  16 , switch connector box  110  is electrically coupled to rail system grounding path  136  at a single connection point on rail system  16  without individual wired connections between each individual component of rail system  16  and switch connector box  110 . 
     Electronics grounding path  138  is formed by the electrical connection between switch connector box  110  and PV modules  18 . Specifically, electronics grounding path  138  extends through metallic frame  70  of a respective PV module  18 , through metallic frame attachment bracket  72 , through metallic housing  66  of micro-inverter  64 , through ground lead wire  90  of micro-inverter  64 , through ground lead wire  50  of extension harness  42 , and to ground lug  116  within switch connector box  110 . Because PV modules  18  are electrically isolated from one another by the anodized surface coating of metallic frames  70  and lack weebs or other wired connections between adjacent modules, electronics grounding path  138  is absent a direct electrical connection between PV modules  18 . 
     The electrical connection between home run grounding path  134 , rail system grounding path  136 , and electronics grounding path  138  is completed within switch connector box  110 . As shown in  FIG. 4 , ground lead wire  126  of home run cable  128  is electrically coupled to extension harness  42  by way of the grounded connection between ground lead wire  50  of extension harness  42  and ground lug  116 . Ground lug  116  is electrically coupled to rail system  16  either through fastener assembly  112 , in embodiments with a metallic switch connector box  110 , or optional wired connection  118  in embodiments with a non-metallic metallic switch connector box  110 . 
     A multi-circuit PV system  142  is illustrated in  FIG. 6  according to another embodiment of the invention. As multi-circuit PV system  142  includes a number of components similar to components shown in PV system  10  of  FIGS. 1-4 , part numbers used to indicate components in  FIGS. 1-5  will also be used to indicate similar components in  FIG. 6 . 
     Multi-circuit PV system  142  of  FIG. 6  includes a first circuit (C- 1 )  144 , which includes a first pair of building block assemblies  146 ,  148 , and a second circuit (C- 2 )  150 , which includes a second pair of basic building block assemblies  152 ,  154 . Each building block assembly  146 ,  148 ,  152 ,  154  includes a number of PV modules  18  arranged in rows and electrically connected to a connector  52  of a respective extension harness  156 ,  158 , similar to extension harness  42  of  FIG. 2 , which is connected to each PV module  18  within its respective circuit  144 ,  150 . As one skilled in the art will recognize, the number of PV modules  18  within a single circuit may vary from that illustrated in  FIG. 6  and may be selected based on design specifications, such as, for example, the size of the protection circuit breaker in the load panel, and by the NEC. In one embodiment, each circuit  144 ,  150  includes 10-13 PV modules  18 . Likewise, PV modules  18  may be arranged in alternative configurations in each circuit. For example, PV modules  18  may be arranged in a single row, or more than two rows. In any of these configurations, PV modules  18  are supported by n+1 rail sections, where n is the number of rows of PV modules  18 . 
     PV modules  18  are mechanically held in place by rail system  16 , which includes a top metallic rail section  20 , a central metallic rail section  22 , and bottom metallic rail section  24 , which includes a first portion  160  corresponding to first circuit  144  and a second portion  162  corresponding to second circuit  150  in the embodiment illustrated in  FIG. 6 . First grounding bar  26  and second grounding bar  28  are mechanically and electrically coupled to rail sections  20 ,  22 ,  160 ,  162  by fastener assemblies  30  ( FIG. 1 ), which penetrate the anodized coating of the components of rail system  16  and form an equipotential electrical connection therebetween. 
     Each circuit  144 ,  150  includes a respective switch connector box  164 ,  166 , similar to switch connector box  110  of  FIG. 1 , electrically and mechanically coupled to top metallic rail section  20 . A first end  168  of extension harness  156  from first circuit  144  enters into switch connector box  164  and is electrically connected with respective lead wires of a first home run cable  170  to create a current path from first circuit  144  to a building load panel or circuit breaker panel  140 . A second end  172  of extension harness  156  ends at a termination point  174  located adjacent the last PV module  18  of building block assembly  148 . As shown, a first end  176  of home run cable  170  is mechanically connected to switch connector box  164  and a second end  178  of home run cable  170  interfaces with circuit breaker panel  140 . 
     Extension harness  158  from second circuit  150  enters switch connector box  166  in a similar manner and is connected to respective lead wires of a second home run cable  180  that creates a current path from second circuit  150  to the building load or circuit panel  140 . Wired connections between extension harness  156  and first home run cable  170  and extension harness  158  and second home run cable  180  are made in a similar manner as set forth in  FIG. 4 . 
     Beneficially, embodiments of the invention thus provide a simplified system for grounding a photovoltaic system. As described above, PV modules  18  are constructed with a micro-inverter  64  that includes a ground lead that is electrically coupled to the metallic housing  66  of micro-inverter  64  and metallic frame  70  of PV module  18 . An AC module wiring harness  82  carries the ground of the metallic components of the PV module  18  to an extension harness  42 , which includes a ground lead and slotted connections for each PV module within the respective circuit. Ground connections for the metallic components within PV modules  18  may therefore be made during installation by simply plugging the AC module wiring harness  82  of a respective PV module  18  into a slotted connector  52  of the extension harness  42  during installation, rather than using individually placed wires or weebs to ground each individual metallic component of the PV module  18  on-site during the installation process. Likewise, ground connections for each of the metallic components of the rail system  16  of PV system  10  is accomplished on-site during installation simply by fastening the various components of the rail system  16  together, since the star washers  38  penetrate the anodized surface of rail sections  20 ,  22 ,  24  and grounding bars  26 ,  28  when the components are fastened together. As such, the metallic components of rail system  16  are at equipotential and may be connected to the ground lead of extension harness  42  through a single connection point in switch connector box  110 , as described above. 
     In summary, the design of the grounding system described herein significantly simplifies the on-site installation procedure for grounding the metallic components within a PV system by providing a single plug-and-play type connection that grounds the PV modules to the extension harness and an equipotential rail system that may be connected to ground through a single connection point. 
     Therefore, according to one embodiment of the invention, a photovoltaic (PV) grounding system includes a first grounding path comprising an electrical connection between a plurality of support bars of a rail system and a connection box coupled to the rail system. The PV grounding system also includes a second grounding path comprising an electrical connection between the connection box and a plurality of PV modules disposed within the rail system, the second ground path extending from micro-inverter ground leads of the plurality of PV modules, through an extension harness electrically connected to the plurality of PV modules, to a ground connection within the connection box. The PV grounding system further includes a third grounding path that includes an electrical connection between the ground connection within the connection box and a building load panel. The first grounding path, the second grounding path, and the third grounding path are electrically connected within the connection box. 
     According to another embodiment of the invention, a method of manufacturing a photovoltaic (PV) grounding system includes providing a first PV panel having a frame, electrically coupling a metal housing to the frame of the first PV panel, the metal housing having a micro-inverter disposed therein, and coupling a first end of a micro-inverter ground lead to the metal housing. The method also includes assembling a plurality of support bars to form an equipotential rail system, positioning the first PV panel within the rail system, and coupling a second end of the micro-inverter ground lead to an extension harness, the extension harness including a plurality of connection modules electrically coupled to an extension ground lead of the extension harness. The method further includes coupling a connector box to the rail system such that the connector box is at equipotential with the rail system, positioning a first end of the extension harness within the connector box, positioning a load ground lead of a load panel within the connector box, and coupling the load ground lead to the extension ground lead within the connector box. 
     According to yet another embodiment of the invention, a photovoltaic (PV) system includes an equipotential rail system and a first PV circuit. The first PV circuit includes a first multi-module wiring harness disposed within the rail system, a first plurality of PV modules disposed within the rail system, each of the first plurality of PV modules having an internal ground lead electrically coupled to the first wiring harness, and a first connection box mechanically and electrically coupled to the rail system and a ground lead wire of the first wiring harness. The PV system further includes a first home run cable comprising a first end and a second end, the first end mechanically and electrically coupled to the first connection box, and the second end coupled to a ground connection of a circuit breaker panel. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.