Abstract:
The present invention relates generally to a load center. More particularly, the invention encompasses a generator ready load center (GRLC). The present invention is also directed to a novel generator ready load center (GRLC) that operates as a standard load center but is ready to accommodate an automatic transfer switch (ATS) for a standby generator, or a manual transfer switch (MTS) for a portable generator. Further the generator ready load center provides an automatic and manual transfer between primary and secondary power sources. The generator ready load center solves the problem of dangerous back-feeding between the primary power source and the secondary power source.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application claims priority to and the benefit of pending U.S. Provisional Patent Application Ser. No. 61/039,498 filed on Mar. 26, 2008, titled “Generator Ready Load Center,” the entire disclosure of which provisional application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a load center or meter load center combinations. More particularly, the invention encompasses a generator ready load center (GRLC). The present invention is also directed to a novel generator ready load center that operates as a standard load center but is ready to accommodate an automatic transfer switch (ATS) for a standby generator, or a manual transfer switch (MTS) for a portable generator. 
     BACKGROUND INFORMATION 
     There are many situations where it is desired to have an auxiliary power source which can be switched to and from the load, such as, for example, in the event of a commercial power failure or due to excessive power variations. There are many reasons to provide this auxiliary power source. Other situations where backup or standby power supplies are consider important include: automatic banking services, automatic industrial processes, communication and signaling centers for maritime and aerial transportation, radio and television stations, various emergency and security services, and many other residential applications, to name a few. 
     Commercial power alone is generally not considered sufficiently reliable as a sole source of power for such usages. Interruptions commonly occur and loads may vary as other users come on and off the commercial power line. These problems are further compounded due to external factors, such as, weather, accidental damage to a component within the power grid, to name a few. 
     Standby power systems are generally known within the prior art. Such standby power supplies usually comprise a generator, and the generator is typically in a standby mode. Once it is established that the prime power source, typically, from the commercial power grid has ceased to provide the needed power, sensors within the system initiate the powering-on of the standby generator, an ATS (automatic transfer switch) then transfers the load from utility power to the standby generator, which provides the needed power to the critical or essential components and thus a continuous supply of current from the standby generator is provided to the components wired to the back-up load center. When the utility power is restored, the ATS automatically disconnects the standby generator and automatically reconnects the utility power. 
     It has been observed that the majority of the standby generator installations are performed after a home has already been constructed. One main reason is that often a major extended power outage in the home owner&#39;s area triggers a generator purchase. In most all situations the house has been wired and a whole house load center already exists at the time of the generator installation. However, at the time of the generator installation one has to install an ATS, back-up circuits which are physically moved to a new back-up load center, power leads are installed that run to the standby generator, fuel lines, such as gas lines, have to run to the generator site, and then, of course, a generator has to be installed. A typical automatic standby generator uses fuel media, wherein the fuel media is gasoline, natural gas, propane gas, or diesel, to name a few. In such applications often the load center and gas supply are not conveniently positioned close to the generator location, requiring extensive electrical work (often behind walls) and lengthy gas line runs. Installation costs can be substantial for most typical retrofit installations, and this cost does not include the generator or the transfer switch cost. 
     Therefore there is a need for improvement in a load center and in particular for a load center that is generator ready. 
     This invention improves on the deficiencies of the prior art and provides an inventive generator ready load center (GRLC). 
     PURPOSES AND SUMMARY OF THE INVENTION 
     The invention is a novel generator ready load center that provides an automatic and manual transfer between primary and secondary power sources. In accordance with the invention the generator ready load center solves the problem of dangerous back-feeding between the primary power source and the secondary power source. 
     Therefore, one purpose of this invention is to provide a generator ready load center (GRLC) to transfer power between primary and secondary or backup power sources without dangerous back-feeding. 
     Another purpose of this invention is to provide a generator ready load center that operates as a standard load center but is ready to accommodate an ATS (automatic transfer switch) for a standby generator. 
     Still another purpose of this invention is to provide a generator ready load center that operates as a standard load center but is ready to accommodate a MTS (manual transfer switch) for a portable generator. 
     Yet another purpose of this invention is to provide a generator ready load center that has two separate and distinct sections, a first section for non-essential circuits, and a second section for essential (emergency) circuits. 
     Yet another purpose of this invention is to provide a robust designed generator ready load center for home, commercial and industrial use. 
     Therefore, in one aspect this invention provides a generator ready load center that includes an enclosure having at least one base pan. A first set of bus bars is secured to a first area of the base pan, and a second set of bus bars secured to a second area of the base pan. At least one non-essential circuit is secured to the first set of bus bars and at least one essential circuit secured to the second bus bars. The first set of bus bars and the second set of bus bars are powered from a utility power source. Upon failure of power from the utility power source the generator ready load center has at least one means for switching to a standby power source such as a generator without dangerous back-feeding. 
     In another aspect this invention comprises a load center for optionally installing capability for switching between a plurality of power sources. The load center has an enclosure having at least one base pan portion having means for mounting a plurality of sets of bus bars. The plurality of sets of bus bars are organized into groups of sets of bus bars and the base pan is subdivided into a plurality of areas into which one group of the groups of the sets of bus bars are secured to each area of the plurality of areas of the base pan. Each set of bus bars of a first portion of the groups of sets of bus bars have at least one primary circuit secured to the set of bus bars and each set of bus bars of a second portion of the groups of sets of bus bars have at least one secondary circuit secured to the set of bus bars. Each of groups of sets of bus bars receives power from one of the plurality of primary power sources. The load center further includes at least one means for switching from one of the plurality of power sources to another of the plurality of power sources to deliver power to at least one of the sets of bus bars without dangerous back-feeding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Although the scope of the present invention is much broader than any particular embodiment, a detailed description of embodiments follows together with drawings. These drawings are for illustration purposes only and are not drawn to scale. Like numbers represent like features and components in the drawings. The invention may best be understood by reference to the ensuing detailed description in conjunction with the drawings in which: 
         FIG. 1  illustrates one method of installing a standby generator. 
         FIG. 2  illustrates a typical installation of a standby generator using the inventive generator ready load center (GRLC). 
         FIG. 3  illustrates a typical installation of a portable generator using the inventive generator ready load center (GRLC). 
         FIG. 4  illustrates a first embodiment of a generator ready load center (GRLC) of this invention. 
         FIG. 5  illustrates a detailed inside view of a generator ready load center (GRLC) of  FIG. 4 . 
         FIG. 6  is a detailed perspective view showing several of the interior components of the generator ready load center (GRLC) of  FIG. 4 . 
         FIG. 7  is a detailed perspective view showing the main lug interior of the generator ready load center (GRLC) of  FIG. 4 . 
         FIG. 8  is a detailed perspective view of the interior of the generator ready load center (GRLC) of  FIG. 4 , showing a split-bus arrangement. 
         FIG. 9  is another detailed perspective view of the generator ready load center (GRLC) of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     The inventive generator ready load center is a dual purpose apparatus. First its design allows it to be used as a standard load center, such as, by utilizing both the upper and lower interiors without any modifications. Secondly, its design allows for it to be “ready” from the factory to have an automatic transfer switch (ATS) installed and to convert it into a standby generator circuit protection system. And, one would install a manual transfer switch (MTS) to convert it into a portable generator circuit protection system. 
     The GRLC (generator ready load center) unit can be made using several designs. The GRLC is a main breaker load center or a lug load center that is placed either on the interior of an enclosure or building or on the exterior of the enclosure or building. Further, the form of the GRLC is in the form of a standardized load center, a meter-load center combination, or a panel board. The GRLC may have a variety of circuit combinations. 
       FIG. 1  illustrates one method  50  of installing a standby generator  58 . In a typical set-up a load center  52  is installed in a room or area  60  where power leads  51  and a utility meter  57  are electrically connected to the load center  52 . The room or area  60  is typically selected from a group comprising a utility room, a garage, a basement, a hallway, a closet, to name a few. Typically, a wall  62  separates the room or area  60  from the external environment  64  such as, outdoor  64 . For the purposes of illustration the optional junction box  56  and the utility meter  57  are shown in the external environment  64  however, they can as easily be installed in the room or area  60  or some other location. There are usually two reasons to install a standby generator or a portable generator. The first and most common reason is that often after a major extended power outages in the area, the purchases of a standby generator is triggered. The second is either due to code compliance or as a back-up power source. In each case a new back-up load center  54  is installed where the back-up or essential circuits are physically moved from the load center  52  and installed into the new back-up load center  54 . An automatic transfer switch (ATS)  53  or a manual transfer switch (MTS)  53  is then installed between the non-essential load center  52  and the essential or back-up load center  54  and the power leads  55  are connected to the automatic transfer switch  53 . Power leads  55  then run to an optional junction box  56  which is connected to the standby generator  58 . Typically, a fuel source line  59  such as, a gas line  59  runs the generator  58 . It is preferred that that fuel source line  59  carries fuel such as gasoline, natural gas, propane gas, or diesel, to name a few. For such applications often the load center  52  and the gas supply  59  are not conveniently positioned close to the generator location, requiring extensive electrical work (often behind walls) and lengthy gas line runs. Installation charges can be rather substantial for most typical retrofit installations and these costs do not include the cost of the generator  58  or the cost of the automatic transfer switch  53 . 
       FIG. 2  illustrates a typical installation  70  of a standby generator  58  using the inventive generator ready load center (GRLC)  23 . The GRLC  23  can be installed initially in place of the load center  52  or the GRLC  23  could be installed as a replacement for the load center  52  automatic transfer switch  53  and the back-up load center  54 . The power leads  55  now run from the generator ready load center)  23  to the junction box  56 . After the GRLC  23  has been installed and there is a subsequent requirement to install a stand-by generator  58  all one has to do now is to install an automatic transfer mechanism  30  or an ATS (automatic transfer switch)  30  into the GRLC  23  and then install the generator  58 . The gas lines  59  or fuel lines  59  again run to the standby generator  58 . 
       FIG. 3  illustrates a typical installation  65  of a portable generator  68  using the inventive generator ready load center (GRLC)  23 . Prior to the installation of the portable generator  68  the room or area  60  already has the GRLC  23  installed. When the portable generator  68  needs to be installed, one connects the power cord  69  from the portable generator  68  to the inlet box  56 . A mechanical interlock  35  or a manual transfer switch (MTS)  35  is then installed inside the GRLC  23  and the portable generator  68  is ready to provide service. 
     As one can see that the initial installation of the GRLC  23  illustrated in  FIG. 2  and  FIG. 3 , gives the owner the option to install the standby generator  58  or the portable generator  68  either during the initial installation of the GRLC  23  or whenever one desires to install the stand-by generator  58  or the portable generator  68 . 
     With this invention the cost of the GRLC  23  is on the same order of magnitude as a regular  40  circuit load center  52 . Additionally, the automatic transfer mechanism installed inside the GRLC  23  is significantly less expensive than a typical automatic transfer switch (ATS)  53 . Furthermore, as one can see that the final installation uses fewer components, making better use of real estate, and also providing for a much cleaner looking installation. 
       FIG. 4  illustrates a first embodiment of a generator ready load center (GRLC)  23  of this invention. The GRLC  23  comprises a standard housing or enclosure  10  having a cover  11 . The GRLC  23  has a main circuit breaker ( 14 ) that can disconnect power to the entire load center. The main circuit breaker ( 14 ) can be replaced by main lugs. The main (utility) power source lands on the main breaker ( 14 ). The upper circuit breaker ( 16 ) funnels the power from the upper interior to the lower circuit breaker ( 18 ), which in turns powers the lower interior. Non-essential circuits are wired in the upper interior and are only powered by the utility power. Critical circuits are wired in the lower interior and are powered by the utility and standby power sources. 
       FIG. 5  illustrates a detailed inside view of a generator ready load center (GRLC)  23  of  FIG. 4  with the cover  11  removed. The generator ready load center (GRLC)  23  has at least one base pan  25 . The base pan  25  has a first or non-essential circuit section  21  and a second or essential (emergency) circuit section  31 . The first circuit section  21  has a first or upper interior set of bus bars  22 . The second circuit section has a second or lower interior set of bus bars  24 . Electrical connections  27  connect the upper circuit breaker  16  to the lower circuit breaker  18  to thus connect the upper set of bus bars  22  to the lower set of bus bars  24 . The electrical connection  27  can be a jumper wire, bus bars or any other sufficiently conductive material. The base pan  25  also has a mounting area  26  for an ATS (automatic transfer switch)  30  (shown in  FIG. 6 ), and a location  29  for the installation of the non-automatic generator switch  34  (shown in  FIG. 6 ). As shown in  FIG. 5 , the GRLC  23  interior is designed with two bus structures, namely, the first or upper interior bus structure  21  that contains the first or upper bus bars  22  and the second or lower interior bus structure  31  that contains the second or lower bus bars  24 . The upper interior bus section  21  is connected to the utility power source. As stated earlier, the circuits in the upper portion  21  are considered non-essential circuits, and are referred to as the non-essential circuit section  21 , which under an emergency situation, such as, utility power failure, would not be required for normal operations. The lower interior section  31  contains all circuits considered essential under emergency conditions that are referred to as the essential (emergency) circuit section  31  by the user or owner. The lower interior bus bars  24  are sub-fed from a 2-pole breaker  18  or lug block. The 2-pole breaker  18  is powered by the upper interior bus bars  22  and a 2-pole non-automatic switch or circuit breaker  16 . This connection allows continuous use of utility power in both interiors  21   31  under normal operating conditions, and powered by the generator only in the second section  31 . It should be appreciated that the first circuit breaker  16  feeds utility power to the second circuit breaker  18  powering the second section  31  with power from the first section  21 . 
       FIG. 6  is a detailed perspective view showing several of the interior components of the generator ready load center (GRLC)  23  of  FIG. 4 .  FIG. 6 , shows that with the installation of the standby generator  58  an automatic transfer switch (ATS)  30  would be installed in the GRLC  23 . The ATS  30  has another 2-pole non-automatic switch or circuit breaker  34  which is installed to allow power connection from the onsite standby generator  58  without dangerous back-feeding. With this arrangement of the ATS  30  added non-automatic switch or circuit breaker  34  installed in the lower interior section  31  and voltage sensing breaker  36  installed in the upper section  21  for the generator  58  can now be mechanically switched back and forth between the utility power source and the standby generator power source by turning the two non-automatic switches or circuit breakers for the second section  31  to their respective on/off positions. In a utility power outage condition only the lower interior section  31  will be energized since the GRLC  23  design allows the ATS  30  to isolate the upper interior section  21  from being energized simultaneously. The non-automatic standby generator switch  34  is powered by the standby generator  58  of  FIGS. 2 and 68  of FIG.  3 . 
       FIG. 7  is a detailed perspective view showing the main lug interior of the generator ready load center (GRLC)  23  of  FIG. 4 . The automatic transfer switch (ATS)  30  has a first arm  42  and a second arm  44 . Motions of the arms  42  and  44  is triggered by the presence or absence of the utility power. The arms  42  and  44  deactivate the connection to the utility power and activate the generator in sequence to prevent dangerous back-feeding. 
       FIG. 8  is a detailed perspective view of the interior of the generator ready load center (GRLC)  23  of  FIG. 4 , showing a split-bus arrangement. As one can see that area  29  and area  39  distinctly separates the first or non-essential circuit section  21  having the first or upper interior bus bars  22  from the second or essential (emergency) circuit section  31  having the second or lower interior bus bars  24  and that there is no electrical connection between the first section  21  and the second section  31  at the base level. 
       FIG. 9  is another detailed perspective view of the generator ready load center (GRLC)  23  of  FIG. 4 . During power transfer from the primary or utility power to the secondary backup or generator power, a switching means  49 , such as, a rotary dial  49 , a sliding switch  49 , to name a few, pushes the second arm  44  causing the second circuit breaker  18  to turn OFF, and turning the generator non-automatic switch  34  to the ON position switching between the utility power and the generator power without dangerous back-feeding. When the utility power is restored the switching means  49  then pushes the first arm  42  causing the generator non-automatic switch  34  to turn OFF, and turns the second circuit breaker  18  to the ON position. 
     With this invention, a user is provided a means for installing an automatic transfer switch (ATS)  30  that will control the switching from utility supplied electrical power to that supplied by an onsite standby generator  58  in the event of a power outage and then back to the utility source after utility power is restored without dangerous back-feeding. The generator ready load center (GRLC)  23  is designed to be installed with the intent of being utilized as a standard load center with the provisions of giving the owner the option of converting it to a unit that can have critical circuits fed by a standby generator with the simple installation of an ATS  30  and associated field wiring. The GRLC  23  design facilitates the avoidance of having to completely rework previously existing wiring. 
     With the inventive generator ready load center (GRLC)  23 , one can save substantial amounts of money in future generator installation expenses while keeping initial expenses to a minimum. As shown in  FIG. 2  and  FIG. 3 , the generator ready load center (GRLC)  23  can be used with an automatic standby generator  58  or a portable generator  68  respectively. 
     The installation of the transfer mechanism can be performed at the time of the generator installation. The automatic transfer switch (ATS) operates automatically when connected to the generator and transfers the load from the utility to the generator and then back to the utility. 
     Instead of having one interior like standard load centers  52  the inventive GRLC  23  has two interiors. During normal operating utility conditions, both interiors are powered. However, during generator back up conditions, only the essential or lower interior containing critical circuits is powered. Since standby generators are hard wired into the location&#39;s electrical system, and then plumbed into the fuel source  59  such as, natural gas  59  or a propane supply  59  installing them after the location construction is complete can be costly and time consuming. During construction, a GRLC  23  can be installed eliminating the need for future rewiring. Pre-planning on the installer&#39;s part also includes running a gas line to the future generator site, and installing a junction box. GRLC  23 All circuit spaces are powered by utility power. Selected circuits are also backed up by the generator  58  or portable generator  68 . 
     While the present invention has been particularly described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. The embodiments as described provide a switching between a utility power source and an auxiliary generator. It will be apparent to those skilled in the art that the auxiliary power sources may be batteries, fuel cells or other ways of generating auxiliary backup power. It will further that it is in keeping with intent of the present invention that the primary power is not the utility power source but a wind generator or solar cells that fail to generate (no wind or low light levels) or other types of generating systems. The secondary power may in fact be the utility power source. Even further, the load center may have more than the two essential and nonessential areas having sets of bus bars and being capable of handling multiple power sources such that the primary power source for an area of the of the load center is switched to a secondary power source and even to other power sources. The automatic transfer switch and the manual transfer switch are in this embodiment able to transfer the bus bars within a given area to any one of multiple power sources without dangerous back-feeding. 
     It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.