WO2009114766A2

WO2009114766A2 - Junction box for solar panels

Info

Publication number: WO2009114766A2
Application number: PCT/US2009/037092
Authority: WO
Inventors: Gary E. Allen
Original assignee: Luma Resources, Llc
Priority date: 2008-03-14
Filing date: 2009-03-13
Publication date: 2009-09-17
Also published as: WO2009114766A3

Abstract

An electrical junction box assembly and a method for its use with a solar electric panel mounted on a roof. The solar panel has a junction mounted on a portion of it with wiring leading from the junction for conducting electricity generated by the panel. The junction box includes a watertight enclosure defining at least one chamber for enclosing and protecting the junction. The enclosure has a support surface for supporting the junction above the roof. The support surface defines a wire inlet opening leading into the chamber to provide clearance for the wiring from the junction to pass into the chamber.

Description

JUNCTION BOX FOR SOLAR PANELS

This patent claims the benefit of the filing dates of the following U.S. provisional patent applications: 61/148,463, filed January 30, 2009; 61/053,174, filed May 14, 2008; and 61/036,631, filed March 14, 2008.

TECHNICAL FIELD The subject invention relates to solar roofing technology, and more specifically to a device and method for interconnecting the wiring from an array of solar roofing panels that have been mounted on a roof.

BACKGROUND OF THE INVENTION

Solar roofing panels produce electricity that travels away from the panel via wiring toward some place where the electricity can be used. In a typical case, each panel has a junction that interconnects the panel and the electrical wiring that leads away from the panel. The wiring will then connect with other wiring from other panels. One challenge is to protect the junction and the wiring from the outdoor environment (rain, snow, wind, sun) that can degrade the junction. Another challenge is to protect the connections where several wires connect together. A third challenge is to do these things in a simple and inexpensive way that is repeatable and dependable. This is particularly important on low slope roofs, where water can collect and even sometimes cover the wiring.

Some people try to meet these challenges by covering the wiring and connections with sheet metal structures to create makeshift conduits and junction boxes on top of the roof. This can be both ineffective and expensive because quality and efficiency will vary from roofer to roofer.

Other people try to penetrate the roof and run the wiring under the roof, but this is also problematic. First, it is rarely desirable to penetrate a new roof because it can lead to voiding of the warranty from the roofer. The roofer will not want to guarantee a roof that has been penetrated by a solar installer, because such penetration can lead to leaking and degradation of the roof. Second, it can be difficult and expensive for an electrician to attempt electrical connections in tight, dark spaces under the roof.

SUMMARY OF THE INVENTION AND ADVANTAGES According to one aspect of the invention, there is an electrical junction box assembly for use with a solar panel mounted on a low-slope roof, where the solar panel has a junction mounted on a portion of it with wiring leading from the junction for conducting electricity generated by the panel. The junction box includes a watertight enclosure defining at least one chamber for enclosing and protecting the junction. The enclosure has a support surface for supporting the junction above the roof. The support surface defines a wire inlet opening leading into the chamber to provide clearance for the wiring from the junction to pass into the chamber.

According to another aspect of the invention, there is a system of electrical junction boxes for solar electric roofing panels, where the roofing panels each have a portion with an electrical junction having electrical wiring leading from it. The system includes first and second junction boxes each having a conduit port, and a wire-conducting conduit having a first end for engaging the conduit port on the first junction box and a second end for engaging the conduit port on the second junction box. In this way, wiring can extend between the first and second junction boxes and be protected in the conduit. Each of the junction boxes includes an access opening and a removable lid for closing the access opening. Each of the junction boxes also defines a junction opening for receiving the junction and the wiring. And each of the junction boxes includes a support surface disposed around the junction opening for supporting the portion of the roofing panel that has the junction.

According to a third aspect of the invention, there is a method for installing a series of solar electric panels on a low-slope roof. The method generally includes the steps of: placing a panel on a roof, where the panel has a junction with electrical wiring leading from it; enclosing the junction and the wiring in a watertight chamber having an access opening and at least one conduit opening; conducting wiring from another solar electric panel into the chamber through the conduit opening; connecting the wiring from the panels in the chamber using the access opening; and sealing the access opening.

Accordingly, the present invention in its various manifestations provides a simple, reliable and repeatable way to protect the wiring systems in an array of solar roofing panels. The junction and the connections are all enclosed in a simple enclosure, and the enclosure is easy to access for both the solar installer and the electrician. Moreover, there is no need to penetrate the roof to run the wiring and make the connections. This provides an effective solution for roofers who are installing commonly-used and widely-manufactured solar roofing panels. It does not require that the roofers obtain specialized knowledge or specialized techniques. FIGURES IN THE DRAWINGS

Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Figure 1 shows an array of junction box assemblies on a low-slope roof; Figure 2 is an exploded side perspective view showing the parts of an embodiment, and how the parts fit together;

Figure 3 is a rear perspective view of an embodiment of the junction box assembly with the lid removed; and Figure 4 is a side section view of an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the Figures wherein like numerals indicate like or corresponding parts throughout the several views, a junction box assembly for a solar electrical roofing panel is generally shown at 10. According to one aspect of the invention, there is an electrical junction box assembly 10 for use with an electrical solar panel generally indicated at 12 which is mounted on a low-slope roof. The solar panel 12 has a junction 14 mounted on a portion of it with wiring leading from the junction for conducting electricity generated by the panel 12. The junction box assembly 10 includes a watertight enclosure generally indicated at 16 defining at least one chamber for enclosing and protecting the junction 14. The enclosure 16 has a support surface 20 for supporting the junction 14 above the roof, and the support surface defines a wire inlet opening 22 leading into the chamber 18 to provide clearance for the wiring from the junction 14 to pass into the chamber. The junction 14 may be a one-piece or a multiple piece junction. Figure 2 shows a two-piece junction 14. The exact form of the junction 14 is not critical to the invention.

The junction box assembly 10 further includes a panel cover 24 for engaging the enclosure 16 and extending over and holding the portion of the solar panel 12 tightly between the panel cover 24 and the support surface 20 to create or effect a watertight seal for the inlet opening 22. The panel cover 24 can be separable from the enclosure 16, or it can be pivotally attached. There may also be a mechanism to secure the panel cover to the enclosure, such as a snap-fit mechanism 26a, 26b or a fastener. As illustrated, especially in Fig. 4, the support surface 20 can slope up from the roof when the junction box assembly 10 mounts on the roof whereby the portion of the solar panel forms an angle with the roof and the junction 14 is supported above the roof. Considered another way, the support surface 20 angles down toward the roof. Other orientations are possible, considering that one goal is to enclose the junction 14 in order to protect it from water.

The enclosure 16 and any corresponding lids and covers 24, 28 may be made with a suitable plastic or composite that is molded in some fashion - e.g. injection molded or by means of casting. The size and exact shape of the enclosure 16 and lids or covers 24, 28 may vary depending on the type of solar panel used and the type of roof. The enclosure 16 defines at least one chamber by including a bottom, walls extending up from the bottom, and lids or covers. There may be more than one interconnecting chamber - e.g. a chamber for receiving the junction 14 that leads into another chamber for housing various wiring, connectors, and related components.

There are a variety of ways to promote sealing around the inlet opening 22. First, the enclosure 16 may include sealing material 30 disposed on the support surface (or between the support surface and the solar panel) around the inlet opening 22 to promote a watertight seal around the opening when the portion of the solar panel 12 is supported on the support surface 20. The enclosure 16 may also include additional sealing material 32 disposed on the panel cover 24 (or between the panel cover and the solar panel) for engaging the portion of the solar panel 12 and pressing it against the support surface 20 to seal the inlet opening 22. The sealing material may be a gasket, O-ring, caulk, or other suitable material that pressures, pushes or biases the solar panel 12 against the support surface 20 around the inlet opening 22. The enclosure 16 defines at least one conduit port or opening 34 for receiving a conduit 36 that conducts wiring to the junction box assembly 10, and providing clearance for the wiring to pass into the chamber 18. The conduit 36 may be a PVC tube interconnecting two junction box assemblies 10. The port 34 may be a tubular piece slightly larger than the diameter of the conduit 36 to receive the conduit in a telescoping manner; and it may include O-rings, caulk, welding, or other seals to seal the connection between the conduit and the port. The port 34 may be formed as an integral part of the enclosure 16, or it may be formed separately and attached to the enclosure.

The enclosure 16 further defines an access opening 38 into the chamber 18 that is spaced apart from the wire inlet opening 22 and the conduit ports 34. A lid or cover 28 can be moveably disposed over the access opening 38. The lid 28 can be removable or pivotally attached to the enclosure 16. This allows access into the chamber 18 to connect or disconnect the wires, or to close and seal the chamber 18 to protect the wiring. The assembly 10 may also include a suitable seal 40 to promote a watertight seal between the enclosure 16 and the lid 28.

The enclosure 16 may house a variety of electrical features in the chamber. For example, it is possible to include electrical posts disposed in the chamber to promote firm connections for the wiring. Other electrical components like inverters or filters may also be disposed in the chamber. The junction box assembly 10 is beneficially designed for thin film photovoltaic (P .V.) panels or modules to be adhered to a low-pitched roof (generally about 0.25 inch per foot or more) or a no-pitch (i.e. flat) roof. But it can be used with other P.V. solar modules (e.g. crystalline) or panels on steeper roofs. Steeper roofs can certainly benefit from this technology, which provides an easy way to seal electrical connections on any roof.

Manufacturing considerations can affect the design of the junction box assembly 10. As shown in the figures, the enclosure 16 is basically flat on the bottom so that it sits on the roof in a stable manner. The enclosure 16 and the lids and covers 24, 28 can be injection molded; and if they are, then the support surface 20 can be molded as an item separate from the rest of the enclosure 16. The support surface can be secured to the enclosure by way of glue, or with fasteners 44 that screw into the bottom of the enclosure 16 and the bottom of the support surface 20. It can also be secured at least partially with a snap-fit connection 42a, 42b. A seal 46 may be disposed between the support surface 20 and the enclosure 16.

According to another aspect of the invention, there is a method for installing a series of solar electric panels 12 on a low-slope roof. The method generally includes the steps of: placing a panel 12 on a roof, where the panel has a junction 14 with electrical wiring leading from it; enclosing the junction 14 and the wiring in a watertight chamber 18 having an access opening 22 and at least one conduit opening 38; conducting wiring from another solar electric panel 12 into the chamber 18 through the conduit opening or port 34; connecting the wiring from the panels 12 in the chamber 18 using the access opening 38; and sealing the access opening. The method may further include the step of sealing the conduit opening 34. The junction 14 is mounted on a portion of the panel 12, and the step of enclosing the junction 14 includes supporting the portion of the panel 12on a watertight enclosure 16 having a junction opening 14 to receive the junction 14 and the electrical wiring. The step of enclosing the junction 14 further includes pressing the portion of the panel 12 against the enclosure 16 around the junction opening 22. The "pressing" step can involve mounting a panel cover or lid 24 on the enclosure 16 over the portion of the panel.

If desired, the entire junction box assembly 10 can be glued or otherwise secured to the roof. The junction box assembly 10 will remain there permanently, but the wiring inside the junction box assembly can be adjusted, replaced, changed, re- run, etc. simply by removing the lid 28 over the access opening. The lid 28 should be replaced afterward in order to protect whatever wiring and components are in the junction box assembly 10.

According to another aspect of the invention, there is a system of electrical junction boxes 10 for solar electric roofing panels 12, where the roofing panels 12 each have a portion with an electrical junction 14 having electrical wiring leading from it. The system generally includes a first junction box 10 having a conduit port 34; a second junction box 10 having a conduit port 34; a wire-conducting conduit 36 having a first end for engaging the conduit port on the first junction box and a second end for engaging the conduit port on the second junction box. In this way, the wiring can extend between the first and second junction boxes 10 and be protected in the conduit 36. Each of the junction boxes 10 includes an access opening 38 and a removable lid 28 for closing the access opening. Each of the junction boxes 10 also defines a junction opening 22 for receiving the junction 14 and the wiring. Each of the junction boxes 10 also includes a support surface 20 disposed around the junction opening 22 for supporting the portion of the roofing panel 12 that has the junction 14 mounted on it. Each junction box 10 includes a lid 24 adapted to extend over the portion of the roofing panel 12 to press it against the support surface 20 and thereby seal the junction opening 22. This technology will allow the roofing contractor, who holds the warranty for the roof, to set the solar panels 12 on the roof and walk away. The electrician may then follow behind with the junction boxes 10 and interconnect the array of solar panels, similar to any electric device on the roof such as an air conditioner. In such a situation, there is no need for penetration of the roof. The wires will be run on the outside of the building, or through roof curb typical to roofing.

The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. Moreover, the reference numerals are merely for convenience and are not intended to be in any way limiting.

Claims

We Claim:

1. An electrical junction box assembly for use with a solar panel mounted on a roof, where the solar panel has a junction mounted on a portion of it with wiring leading from the junction for conducting electricity generated by the panel, the junction box assembly comprising: a watertight enclosure defining at least one chamber for enclosing and protecting the junction; the enclosure having a support surface for supporting the junction above the roof; and the support surface defining a wire inlet opening leading into the chamber to provide clearance for the wiring from the junction to pass into the chamber.

2. The junction box assembly of claim 1 further including a panel cover for engaging the enclosure and extending over and holding the portion of the solar panel tightly between the panel cover and the support surface to effect a watertight seal for the inlet opening.

3. The junction box assembly of claim 1 wherein the enclosure further defines an access opening into the chamber that is spaced apart from the wire inlet opening.

4. The junction box assembly of claim 3 further including a lid moveably disposed over the access opening to alternately permit access into the chamber to connect or disconnect the wires, or to close and seal the chamber to protect the wiring.

5. The junction box assembly of claim 1 further including sealing material disposed on the support surface around the inlet opening to promote a watertight seal around the opening when the portion of the solar panel is supported on the support surface.

6. The junction box assembly of claim 1 further including sealing material disposed on the panel cover for engaging the portion of the solar panel and pressing it against the support surface to seal the inlet.opening.

7. The junction box assembly of claim 1 wherein the roof is a low-slope roof.

8. The junction box assembly of claim 1 wherein the enclosure defines at least one conduit port for receiving a conduit that conducts wiring to the junction box assembly, and providing clearance for the wiring to pass into the chamber.

9. The junction box assembly of claim 1 wherein the support surface slopes up from the roof when the junction box assembly mounts on the roof whereby the portion of the solar panel forms an angle with the roof and the junction is supported above the roof.

10. A method for installing a series of solar electric panels that have been set on a roof, where each panel has a junction with electrical wiring leading from it, the method including the steps of: enclosing the junction and the wiring in a watertight chamber having an access opening and at least one conduit opening; conducting wiring from another solar electric panel into the chamber through the conduit opening; connecting the wiring from the panels in the chamber using the access opening; and sealing the access opening.

11. The method of claim 10 further including the step of sealing the conduit opening.

12. The method of claim 10 wherein the junction is mounted on a portion of the panel, and the step of enclosing the junction includes supporting the portion of the panel on a watertight enclosure having a junction opening to receive the junction and the electrical wiring.

13. The method of claim 12 wherein the step of enclosing the junction further includes pressing the portion of the panel against the enclosure around the junction opening.

14. The method of claim 13 wherein the step of pressing the portion includes mounting a lid on the enclosure over the portion of the panel.

15. The method of claim 10 wherein the step of sealing includes covering the junction with a cover.

16. A system of electrical junction box assemblies for solar electric roofing panels, where the roofing panels each have a portion with an electrical junction having electrical wiring leading from it, the system including: a first junction box assembly having a conduit port; a second junction box assembly having a conduit port; a wire-conducting conduit having a first end for engaging the conduit port on the first junction box assembly and a second end for engaging the conduit port on the second junction box assembly whereby wiring can extend between the first and second junction box assemblies and be protected in the conduit; each of the junction box assemblies including an access opening and a removable lid for closing the access opening; each of the junction box assemblies defining a junction opening for receiving the junction and the wiring; and each of the junction box assemblies including a support surface disposed around the junction opening for supporting the portion of the roofing panel that has the junction.

17. The system of claim 16 wherein each junction box assembly includes a lid adapted to extend over the portion of the roofing panel to press it against the support surface and thereby seal the junction opening.

18. The system of claim 17 further including material between the lid and the portion of the roofing panel to press it against the support surface and thereby seal the junction opening.