Abstract:
A power interface operable to direct power from one of a first source and a second source to a load. The power interface includes a support plate, and a switch extending through the support plate. The switch is electrically connected to the first source and to the load and is movable between a first switch position in which power from the first source is directed to the load, and a second switch position in which power from the first source is inhibited from reaching the load. An electrical connector is electrically connectable to the load and is connectable to the second source to facilitate the delivery of power from the second source to the load. A movable cover is movable between a first cover position in which the cover inhibits connection between the electrical connector and the second source and a second cover position.

Description:
BACKGROUND  
       [0001]     The invention generally relates to power distribution. In particular, the invention relates to power distribution from a primary power source or a secondary power source to an appliance.  
         [0002]     Residential electrical loads such as furnaces are typically hardwired to an ON-OFF switch box or a load power switch. Unless an automatic transfer switch and a backup power generator are used, supplying electricity to the furnace with a portable generator when there is a power outage is very difficult. When there is no transfer switch and since the portable generator has to be run outdoors, generator extension cords will run from the portable generator to the load via a window or a door.  
         [0003]     Standby back up generators are also known. Such standby generators typically use an automatic transfer switch. However, the automatic power switching and the typical standby power generator are costly, and generally require an electrician to install.  
       SUMMARY  
       [0004]     The invention provides a power interface operable to direct power from one of a first source and a second source to a load. The power interface includes a support plate, and a switch extending through the support plate. The switch is electrically connected to the first source and to the load and is movable between a first switch position in which power from the first source is directed to the load, and a second switch position in which power from the first source is inhibited from reaching the load. An electrical connector is electrically connectable to the load and is connectable to the second source to facilitate the delivery of power from the second source to the load. A movable cover is movable between a first cover position in which the cover inhibits connection between the electrical connector and the second source and a second cover position.  
         [0005]     The invention also provides an alternate power source connection kit operable to direct power from one of a utility source and an alternative source to a load. The connection kit includes a support plate adapted to connect to an electrical box and an electrical connector coupled to the support plate. The electrical connector is selectively electrically connectable to the alternative source and fixedly electrically connectable to the load. A switch is coupled to the support plate and is fixedly electrically connectable to the load and to the utility source. The switch is movable between a first switch position in which the utility source and the load are electrically connected, and a second switch position in which the utility source and the load are not electrically connected. A cover is movably coupled to the support plate and is movable between a first cover position in which the cover inhibits connection between the alternative source and the electrical connector and a second cover position.  
         [0006]     In another construction, the invention provides a power interface operable to direct power from one of a first source and a second source to a load. The power interface includes a support plate and an electrical connector coupled to the support plate and fixedly electrically connected to the load. The electrical connector is selectively connectable to the second source to facilitate the delivery of power from the second source to the load. A cover is movable between a first cover position in which the cover at least partially covers the electrical connector to inhibit connection between the electrical connector and the second source, and a second cover position in which the cover does not inhibit connection between the second source and the electrical connector. A switch is coupled to the support plate and is electrically connected to the first source and to the load. The switch is movable between a first switch position in which the first source is electrically connected to the load and the switch maintains the cover in the first cover position, and a second switch position in which the first source is not electrically connected to the load and the cover is free to move to the second cover position.  
         [0007]     In this way, a user of the generator can choose to keep the original load power switch connected to the load, and thus be able to provide only one source of power at a time, or to disconnect power during maintenance. Additionally, using the original load power switch allows the connection box to occupy a relatively small area, and also results in simple wiring within the connection box. A smaller connection box also generally provides flexibility in installation, and is also relatively less expensive to produce. Furthermore, using the original load power switch allows the connection box to use a two-position switch, which is relatively inexpensive.  
         [0008]     In another embodiment, the invention allows for the connection of a power interface directly to an existing electrical box. Thus, a second box is not required, thereby simplifying the installation. The power interface is preassembled, may be sold as a retrofit kit, and requires only a few electrical connections before attaching the power interface to the box using the same fasteners as the original cover of the box.  
         [0009]     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  shows a do-it-yourself (“DIY”) system for portable generators according to the present invention;  
         [0011]      FIG. 2  shows a first electrical circuit according to present invention;  
         [0012]      FIG. 3  shows a second electrical circuit according to present invention;  
         [0013]      FIG. 4  is a schematic illustration of a portable generator and a power interface according to another embodiment of the invention;  
         [0014]      FIG. 5  is a perspective view of the power interface of  FIG. 4 ;  
         [0015]      FIG. 6  is an exploded perspective view of the power interface of  FIG. 4 ;  
         [0016]      FIG. 7  is a section view of the power interface of  FIG. 4  taken along line  7 - 7  of  FIG. 5 ;  
         [0017]      FIG. 8  is a perspective view of a portion of the power interface of  FIG. 4  including a movable cover in a first position;  
         [0018]      FIG. 9  is a perspective view of a portion of the power interface of  FIG. 4  including a movable cover in a second position;  
         [0019]      FIG. 10  is an electrical schematic illustrating the electrical connections of the power interface of  FIG. 4  with the switch in a first position; and  
         [0020]      FIG. 11  is an electrical schematic illustrating the electrical connections of the power interface of  FIG. 4  with the switch in a second position. 
     
    
       [0021]     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.  
       DETAILED DESCRIPTION  
       [0022]      FIG. 1  shows a do-it-yourself (“DIY”) system  100  for portable generators. The DIY system  100  connects power, either from a generator  104  or from a utility or other alternate source  108  to a hard-wired residential load  112 . The load  112  is generally connected in circuit to a load power switch  116  that switches power to the load  112 . In other embodiments, the load power switch  116  may be integrated with the load  112 .  
         [0023]     Typical hard-wired residential loads include furnaces, air conditioning units, and the like. When the load power switch  116  is in an ON position, the load power switch  116  connects a selected power source to the load  112 . When the load power switch  116  is in an OFF position, the load  112  is disconnected from any power source. In an alternative embodiment, when the load power switch  116  is in the OFF position, the load  112  can be disconnected from the utility power source  108 , but connected to the generator  104 , detailed hereinafter. In the embodiment shown, the load power switch  116  can be an existing load switch for the load  112 .  
         [0024]     The DIY system  100  includes a connection box  128 , and a power conduit  132 . The connection box  128  has a front panel  136 , a back  140 , and a plurality of side panels  144 . The connection box  128  is preferably anchored to a wall at the back  140  of the connection box  128 . The front panel  136  has an input plug  148  or other input connector that receives power from the portable generator  104  via a generator power cord  146 . Although the input connector  148  is shown disposed on the front panel  136  of the connection box  128 , the input connector  148  can also be disposed on one of the side panels  144 . The input connector  148  is a male plug, although other connectors can also be used.  
         [0025]     In one embodiment, the connection box  128  is mechanically connected to the load power switch  116  via the power conduit  132 . The power conduit  132  thus allows the connection box  128  to be placed at any convenient location, or provides a convenient way to at least partially anchor the connection box  128 . Although the connection box  128  and the power conduit  132  are shown disposed above and spaced apart from the load power switch  116 , the connection box  128  and the power conduit  132  can also be placed at other locations such as below the load power switch  116  depending on the location and the accessibility of the load power switch  116 .  
         [0026]     The connection box  128  also has a two-position switch  152  on the side panel  144 . The two-position switch  152  is connected in circuit with the input connector  148  and thus with the generator  104  in its first position. The two-position switch  152  is connected in circuit with the utility source  108  in its second position. Particularly, when the two-position switch  152  is at the first position, and when the load power switch  116  is in the ON position, generator power is delivered from the generator  104  to the load  112  via the input connector  148 . Also, when the two-position switch  152  is at the second position, and when the load power switch  116  remains in the ON position, utility power is delivered from the utility source  108  to the hard-wired load  112 .  
         [0027]      FIG. 2  shows an electrical circuit that may be used with the embodiment in  FIG. 1 , where like parts are referenced with like numerals. In particular,  FIG. 2  shows that the connection box  128 , the load power switch  116 , and the load  112  are connected and wired in series.  FIG. 2  also shows that the connection box  128  receives utility power from the utility source  108  via the power conduit  132  that mechanically connects the connection box  128  and the load power switch  116 .  
         [0028]     Furthermore, power from the portable generator  104  is available at a first two-position switch contact  156  of the two-position switch  152  via the input connector  148 , whereas power from the utility source  108  is available at a second two-position switch contact  160 . Specifically, when the first position of the two-position switch  152  is selected, a connection is made between the first two-position contact  156  and a first throw  164 . When the ON position of the load power switch  116  is selected, a second connection is also made between an ON contact  168  and a second throw  172 , which is also connected to the first throw  164 . As a result, the portable generator  104  is connected to the load  112  in series. Similarly, when the second position of the two-position switch  152  is selected, a third connection is made at the two-position switch  152  between the second two-position contact  160  and the first throw  164 . Selecting the ON position of the load power switch  116 , which makes the second connection at the two-position switch  152 , will connect the utility source  108  and the load  112  in series.  
         [0029]     In an alternate circuit shown in  FIG. 3 , the connection box  128 , the load power switch  116 , and the load  112  are wired or connected differently. In embodiment shown in  FIG. 3 , switching the load power switch  116  and the connection box  128  will result in different electrical connections, and provide installation and usage flexibility. For example,  FIG. 3  shows that power from the utility source  108  is available at the ON contact  168  of the load power switch  116 . Power from the portable generator  104  is shown available at the first two-position switch contact  156  of the two-position switch  152  via the input connector  148 . Furthermore, power from the utility source  108  is available at the second two-position switch contact  160  via the second throw  172 .  
         [0030]     With the wiring arrangement shown in  FIG. 3 , when the ON position of the load power switch  116  is selected, power from the utility source  108  is provided to the two-position switch  152  as an optional power. In this way, selecting a position on the two-position switch  152  will connect power from either the portable generator  104  or the utility source  108  to the load  112 . However, when the OFF position is selected, and if the portable generator  104  is connected to the connection box  128  via the input connector  148 , power from the generator  104  can still be provided to the load  112 . The OFF position on the load power switch  112  therefore indicates power from the utility source has been disconnected. However, the power from the generator  104  may still be present at the load  112 , whereas the ON position simply indicates one of the two power sources has been connected to the load  112 .  
         [0031]     Referring back to  FIG. 2 , the present invention also provides a method of connecting generator power to the hard-wired load  112 , such as a furnace or an air conditioning unit. When the load  112  has a load power switch  116  that switches power to the hard-wired load  112 , the load power switch  116  is first rewired and connected as described hereinafter. The method involves connecting the utility source  108  to the connection box  128 , and receiving power from the generator  104  at the input plug or connector  148  of the connection box  128 . In this way, the utility source  108  is connected to the connection box  128  at the second two-position switch contact  160  of the two-position switch  152  in circuit through the power conduit  132 . After the generator  104  has been connected to the connection box  128  at the input connector  148  on the front panel  136  of the connection box  128 , the generator  104  is connected to the connection box  128  at the first two-position contact  156 . Thus, power from one of the two power sources  104 ,  108  is routed back to the load power switch  116  via the power conduit  132 .  
         [0032]     The method also includes electrically connecting the utility source  108  to the load power switch  116  when the second position of the two-position switch  152  is selected, or electrically connecting the generator  104  to the load power switch  116  when the first position of the two-position switch  152  is selected. That is, when the second position of the two-position switch  152  is selected, the utility source  108  is electrically connected to the load power switch  116  via the second two-position switch contact  160 . On the other hand, when the first position of the two-position switch  152  is selected, the generator  104  is electrically connected to the load power switch  116  via the first two-position switch contact  156 .  
         [0033]     Depending on the position of the load power switch  116 , and the position of the two-position switch  152  on the side panel  144  of the connection box  128 , power from the generator  104  or from the utility source  108  is either delivered to the load  112  or disconnected. For example, switching the load power switch  116  to an OFF position will electrically disconnect any power to the load  112 . Otherwise, switching the load power switch  116  to an ON position will electrically connect power from either the utility source  108  or the generator  104  to the hard-wired load  112 . If the embodiment of  FIG. 2  is used and the load power switch  116  is in its ON position, selecting the first position  156  and the second position  160  of the two-position switch  152  will electrically connect the generator  104  or the utility source  108  to the load  112 , respectively. Similarly, if the embodiment of of  FIG. 3  is used and the load power switch  116  is in its ON position, selecting the first position and the second position of the two-position switch  128  will electrically connect the generator  104  or the utility source  108  to the load  112 , respectively. However, if the embodiment of  FIG. 3  is used but the load power switch  116  is in its OFF position, only selecting the first position of the two-position switch  152  will electrically connect any power source to the load  112 .  
         [0034]     The method also allows for providing a conduit  132  that mechanically connects the connection box  128  and the load power switch  116 , and for receiving power from the utility source  108  at the connection box  128  via the conduit  132 . The power conduit  132  thus allows the connection box  128  to be placed at any convenient location, for example. Furthermore, positioning the two-position switch  152  on one of the side panels  144  of the connection box  128 , for example, allows the connection box  128  to occupy a relatively smaller area, and also provides flexibility in installation. The method also allows for positioning the input plug or connector  148  on the front panel  136  of the connection box  128  to provide easy generator access.  
         [0035]      FIGS. 4-11  illustrate another embodiment of the invention in which an alternative or auxiliary power supply connects to a preexisting electrical box  210 , rather than to a separate electrical box. With reference to  FIG. 4 , the alternative or auxiliary power source in the form of a portable generator  215  is illustrated. The portable generator  215  includes an internal combustion engine  220  that is rotationally coupled to an electric machine  225  (e.g., generator, alternator, etc.) such that operation of the internal combustion engine  220  results in an electrical power output from the generator  215 . While the illustrated construction employs a portable generator  215  to generate the electrical power output and provide the auxiliary power, other constructions may use alternate sources such as wind turbines, water turbines, solar cells, and the like. As such, the invention should not be limited to systems that employ portable generators  215  having internal combustion engines  220  as the prime mover.  
         [0036]     With continued reference to  FIG. 4 , the generated power is output through one of a plurality of connectors  230  mounted on the generator  215 . In the illustrated construction, a power cord  235  extends from one of these connectors and includes a connector  240  that is selectively connectable with a power interface  245 . The power interface  245  is disposed between a load  250  and a primary or utility power source  255 . Generally, a breaker box  260  or fuse box is positioned between the utility power source  255  and the load  250  to inhibit circuit overloads.  
         [0037]     One of ordinary skill in the art will realize that the load  250  could consist of any device or combination of devices that use electricity to function. However, the invention illustrated in  FIGS. 4-10  is particularly well suited for use with single devices that are directly wired to the breaker box  260 . Examples of these types of devices include furnaces, air conditioners, and the like.  
         [0038]     As illustrated in  FIGS. 5 and 6 , the power interface  245  attaches to the box  210  and includes a support plate  265 , a movable cover  270 , an electrical connector  275 , and a switch  280 . In addition, the illustrated construction includes a hanging tag  283  that provides space for operating instructions, installation instructions, and other information that may be useful for the user. Omission of the hanging tag  283  will not affect the operation or construction of the power interface  245 .  
         [0039]     The box  210  generally includes four walls  285  that are interconnected by a rear surface  290 . The four walls  285  cooperate to define a rectangular opening that provides access to a space  295  defined by the four walls  285  and the rear surface  290 . The box  210  also includes two tabs  300  that extend inward from two opposed walls  285 . Generally, each tab  300  includes a threaded aperture  305  positioned and sized to facilitate the attachment of a cover to the box  210 . Boxes  210  of this type are commonly used to house electrical wires and connections within a building.  
         [0040]     The support plate  265  includes two rectangular apertures  310 ,  315 , two fastener apertures  320  (one shown), and three elongated slots  325 . The fastener apertures  320  are sized to receive a fastener  330  and to allow only a portion of the fastener  330  to pass through. The apertures  320  are positioned such that they align with the threaded apertures  305 . Arranged as illustrated, the fasteners  330  can pass through the fastener apertures  320  and threadably engage the box  210  to attach the support plate  265  to the box  210 . While other attachment systems are possible, the illustrated arrangement is preferred because it allows the power interface  245  to attach to many conventional boxes  210  without modification to the box  210 . Rather, the preexisting cover for the box  210  is removed and is replaced by the support plate  265 .  
         [0041]     The switch  280  includes a switch housing  335  that encloses the internal contacts of the switch  280 , and a rocker  340  or other movable member that allows a user to change the connection of the contacts within the switch  280 . In the illustrated construction, a two-position rocker switch  280  or double pole single throw (DPST) switch  280  is employed, with other switch arrangements also being possible. A plurality of connectors  345  extend from the housing  335  to allow for the connection of electrical conductors to the switch  280 . At least four connectors  345  are employed to allow for the connection of the switch  280 , with an additional or ground connector also being possible. As illustrated and discussed with regard to  FIGS. 10 and 11 , the switch  280  includes a hot lead  350  and a neutral lead  355  on an input side  360  of the switch  280 , and a hot lead  365  and a neutral lead  370  on an output side  375  of the switch  280 . When the switch  280  is in a first position, the hot leads  350 ,  365  and the neutral leads  355 ,  370  of the input and output sides  360 ,  375  are connected as shown in  FIG. 10 , and when the switch  280  is in the second position the input and output sides  360 ,  375  are not electrically connected, as shown in  FIG. 11 .  
         [0042]     With reference to  FIG. 6 , the switch housing  335  defines a shoulder  380  that engages the support plate  265  to properly locate the switch  280 . In some constructions, the housing  335  includes a locking member  383  (shown in  FIG. 7 ) that passes through the switch aperture  310  and then springs outward to engage the back of the support plate  265  to lock the switch  280  in position. In still other constructions, a press or tight fit, fasteners, adhesives, or other attachment means is employed to hold the switch  280  in the desired position. Also, it should be noted that the switch aperture  310  is sized and shaped to receive the switch  280 . As such, other constructions that employ other switches may require differently sized or shaped apertures to properly receive the switch.  
         [0043]     The electrical connector  275  includes a housing  385  that defines a recess  390  in which a standard male receptacle  395  is positioned. The illustrated male plug  395  includes three prongs  400  that extend outward from the bottom of the recess but that do not extend beyond the recess. The prongs  400  are arranged to receive the standard female receptacle  240  such as is employed on many 120-volt, 15 amp electrical cords  235 , as shown in  FIG. 4 . Thus, two of the prongs  400  cooperate to at least partially define a circuit, with one of the prongs  400  being the hot prong and the other being the neutral prong, with the third prong  400  being a ground prong. Of course other male plugs, female receptacles, or combinations may also be employed if desired. For example, a 120-volt, 20 amp male plug, or a standard single-phase 240-volt receptacle or plug could be employed as could a three-phase 240-volt connector. Each of these connectors includes a slightly different arrangement than the one illustrated to inhibit the connection of incompatible power sources.  
         [0044]     In the illustrated construction, three connectors extend out the opposite side of the housing  385 , with each connector electrically connected to one of the prongs  400 . Thus, the electrical connectors define a hot lead  405 , a neutral lead  410 , and a ground lead  415  as illustrated in  FIGS. 10 and 11 . The location of the connectors  405 ,  410 ,  415  provides for easy electrical connection to the electrical connector  275  in a way that allows for the wires and all of the connections to be disposed within the box  210 .  
         [0045]     With reference to  FIG. 6 , the electrical connector housing  385  includes a shoulder  420  similar to the switch shoulder  380 . The shoulder  420  engages the support plate  265  to properly locate the electrical connector  275 . As with the switch housing  335 , the electrical connector housing  385  may include a locking member (not shown) that passes through the aperture  315  and then springs outward to engage the support plate  265  to inhibit the unwanted removal of the electrical connector  275 . Alternatively, a press or tight fit, adhesives, fasteners, or the like could be employed to attach the electrical connector to the support plate. Also, it should be noted that the electrical connector aperture  315  is sized and shaped to receive the electrical connector  275 . As such, other constructions that employ other electrical connectors may require differently sized or shaped apertures to properly receive the electrical connector.  
         [0046]     The movable cover  270  includes a plate  425  that could be substantially rectangular or square with approximately one quadrant removed. Alternately the plate may have another shape. The plate  425  includes a central aperture  430  sized to receive the female receptacle  240  or other cord connector. The central aperture  430  is at least partially defined by a switch-engaging surface  435  that extends along a portion of the central aperture  430 . Three pins  440  (two shown in  FIG. 6 ) extend from the rear surface of the plate  425  such that each pin  440  is substantially parallel to the other pins  440  and is substantially normal to the plate  425 . Two pins  440  are located on one side of the plate  425  and are spaced apart a distance defined by the distance between the two slots  325  formed in the same side of the support plate  265 . The third pin  440  is disposed on the opposite side of the plate  425  and engages the slot  325  formed in the opposite side of the support plate  265 . Of course, other constructions may employ fewer or more than three pins  440  or differently arranged or oriented pins  440  if desired. In addition, some or all of the pins  440  may be located on the support plate  265  rather than the plate  425 , with the corresponding slots formed in the plate  425  or the support plate  265 . Alternately, other slide arrangements could be used.  
         [0047]     As illustrated in  FIG. 7 , the pins  440  include a guide portion  445  and a lock-engaging portion  450  that extends from the guide portion  445 . The guide portions  445  are sized to closely engage the elongated slots  325  when the plate  425  is placed adjacent the support plate  265 . Lock washers or connectors  455  slide over the pins  440  behind the support plate  265  and engage the lock-engaging portions  450  to inhibit movement of the plate  425  in a direction substantially parallel to the pins  440 . Thus, the movable cover  270  is constrained to move along a line or in a direction that is substantially parallel to, and defined by the three slots  325  formed in the support plate  265 . The length of the slots  325  also limits the amount of movement of the movable cover  270  such that it is movable between a first position (shown in  FIG. 8 ) and a second position (shown in  FIG. 9 ). In alternate embodiments, other ways could be used to retain the slide.  
         [0048]     To assemble the power interface  245 , one first inserts the switch  280  and the electrical connector  275  into the support plate  265 . Each component  275 ,  280  is simply pushed into the corresponding aperture  310 ,  315  until the corresponding locking members  383  pass through the aperture  310 ,  315  and spring outward to lock the component  275 ,  280  in place. In some arrangements a resilient gasket is positioned between the support plate  265  and the shoulder  380 ,  420  of one or each of the components  275 ,  280  to provide a better seal and to provide a biasing force that holds the locking members  383  against the support plate  265  to inhibit unwanted vibration or movement. The plate  425  is next positioned such that the pins  440  extend through their respective slots  325 . The lock washers  455  slide onto the pins  440  and engage the lock-engaging portion  450  to complete the assembly of the movable cover  270  and to inhibit the removal of the movable cover  270 , while still allowing linear movement of the cover  270 .  
         [0049]     To install the power interface  245 , the user must electrically connect the load  250  and the utility power supply  255  to the power interface  245 .  FIGS. 10 and 11  illustrate one possible circuit arrangement that will allow operation of the power interface  245 . In the illustrated arrangement, the hot lead  350  and neutral lead  355  on the input side  360  of the switch  280  are fixedly electrically coupled to the utility or primary power supply  255 . The hot lead  365  from the output side  375  of the switch  280  is fixedly electrically connected to the hot lead  405  from the electrical connector  275  and a hot lead  460  that extends to the load  250 . Similarly, the neutral lead  370  from the output side  375  of the switch  280  is fixedly electrically connected to the neutral lead  410  from the electrical connector  275  and a neutral lead  465  that extends to the load  250 . Generally, the three hot leads  350 ,  365 ,  460  are connected to one another using a wire nut, a bus, or other connection that electrically connects the three leads  350 ,  365 ,  460 . Similarly, the three neutral leads  355 ,  370 ,  465  are connected to one another using a wire nut, a bus, or other connection that electrically connects the three leads  355 ,  370 ,  465 .  
         [0050]     Arranged as illustrated, the switch  280  is not operatively connected to the electrical connector  275 , as the position of the switch  280  does not affect the operation of the electrical connector  275 . While the switch  280  is electrically connected to the electrical connector  275 , there is no operative relationship.  
         [0051]     Before proceeding, it should be noted that the term “fixedly electrically connected” is intended to cover any electrical connection, that through normal use and operation is not intended to be broken or interrupted. For example, three leads connected with a wire nut are fixedly electrically connected even though the simple, but abnormal, removal of the wire nut would break the connection.  
         [0052]     In use, the user selects the desired source of power by positioning the movable cover  270  and switch  280  as illustrated in  FIG. 8  or  FIG. 9 . To select utility or primary power, the user arranges the power interface  245  as illustrated in  FIG. 8 . Specifically, the user slides the movable cover  270  upward such that the switch  280  is substantially disposed within the cover central aperture  430  and the electrical connector  275  is covered by the movable cover  270 . The switch  280  is moved to the closed position such that the portion of the rocker  340  adjacent the switch-engaging surface  435  extends through the cover central aperture  430 . In this arrangement, the rocker  340  engages the switch-engaging surface  435  and interferes with the downward movement of the cover  270 . Thus, the cover  270 , in the first position illustrated in  FIG. 8 , inhibits access to the electrical connector  275 . Of course, the cover or movable plate could move in another direction, or use another mechanism could be used to cover the plug.  
         [0053]     With reference to  FIG. 10 , with the switch  280  in the first position, the input side  360  and the output side  375  of the switch  280  are connected. Thus, a hot lead  470  from the utility power supply  255  is electrically connected to the hot lead  365  from the output side  375  of the switch  280 , the hot lead  405  from the electrical connector  275 , and the hot lead  460  from the load  250 . Similarly, a neutral lead  475  from the utility power supply  255  is electrically connected to the neutral lead  370  from the output side  375  of the switch  280 , the neutral lead  410  from the electrical connector  275 , and the neutral lead  465  from the load  250 . As such, power is supplied to the load  250  by the utility power supply  255 . However, because the movable cover  270  covers the electrical connector  275 , any power delivered to the electrical connector  275  cannot be used or accessed by the user.  
         [0054]     To switch to the auxiliary power supply or portable generator  215  as described in the present construction, the user first reconfigures the power interface  245  such that it is arranged as illustrated in  FIG. 9 . Specifically, the user first moves the switch  280  to the second position. With the switch  280  in the second position, the movable cover  270  moves downward to expose the electrical connector  275 . In addition, the movable cover  270  covers a portion of the switch rocker  340  such that the switch  280  cannot be easily moved back to the first position. The user engages the female connector  240  from the auxiliary power supply  215  with the electrical connector  275  to feed power to the electrical connector  275 .  
         [0055]     Turning to  FIG. 11 , the hot lead  405  from the electrical connector  275  remains connected to the hot lead  365  from the output side  375  of the switch  280  and the hot lead  460  from the load  250 . Similarly, the neutral lead  410  from the electrical connector  275  remains connected to the neutral lead  370  from the output side  375  of the switch  280  and the neutral lead  465  from the load  250 . As such, power is provided to the load  250  from the auxiliary power supply  215 . The position of the switch contacts (i.e., open) assures that power from the input side  360  is not delivered to the output side  375 , thus cutting off the utility power supply  255 .  
         [0056]     In preferred arrangements, the power interface  245  is provided as a kit that allows the user to install the power interface  245  to allow for easy connection of the auxiliary power supply  215  to the load  250 . In such an arrangement, the power interface  245  replaces the cover of the typical electrical switch box  210  that provides power to the load  250 .  
         [0057]     It should be noted that the term “utility power supply” has been used to describe one of the sources of power for the load  250 . However, there is no requirement that the power supply actually be provided by a utility. For example, the invention described herein will function when the “utility power supply” is provided by a stand-alone power source such as a series of solar cells. In this arrangement, an auxiliary power supply, such as the portable generator illustrated in  FIG. 4  may be employed to provide power when the primary or “utility power” supply is not available, such as, in this example during long periods without sunshine.  
         [0058]     While the construction illustrated in  FIGS. 4-11  has been described as including a double pole single throw switch, another construction includes a double pole double throw switch. The double pole double throw switch is movable to a first switch position in which the switch disconnects the electrical connector from the load and the utility power supply, and connects the utility power supply to the load. The switch can also be moved from the first switch position to a second switch position in which the switch connects the electrical connector to the load and disconnects the utility power supply from the load. IN preferred arrangements a two position double pole double throw switch is employed with other switches also being possible. The use of the double pole double throw switch allows the utility power supply and the electrical connector to be isolated from one another. Specifically, the electrical connector never connects to or receives power from the utility power supply.  
         [0059]     Various features and advantages of the invention are set forth in the following claims.