Patent Publication Number: US-2023133091-A1

Title: Patch panel for programming a split bus electrical panel for partial or full backup with pv and battery systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 17/201,455 filed on Mar. 15, 2021, which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63/093,903 filed on Oct. 20, 2020, the contents of which are incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to residential electrical panels for providing full or partial back-up of a photovoltaic system to power critical loads during a utility power outage. 
     BACKGROUND 
     When an electrical utility outage occurs, critical loads such as pumps, security systems, refrigerators and electronics should ideally have an auxiliary source of power available. In residential applications, photovoltaic (PV) systems with battery back-up are available to provide limited auxiliary power, which is typically at a lower power level than is available from the utility. Thus, some means is required to allocate the reduced power to the critical loads. The installation of typical residential PV systems requires a separate back-up panel for the critical loads, so that the critical loads must be relocated to the separate back-up panel. 
     In typical residential photovoltaic/battery back-up systems, a decision needs to be made prior to installation of the system, as to whether a partial back-up system or full back-up system will be provided for the home. Once the choice is made to install either the partial back-up system or full back-up system, it would require significant labor to reconstruct and rewire the system if the choice of systems were to change. 
     What is needed is a convenient way for the installer implement either a partial back-up system or full back-up system at the time the home is being built, and moreover, to enable an electrician to later change the system, if desired by the home owner. 
     SUMMARY 
     In accordance with one example embodiment described herein, an apparatus provides a single split-bus electrical panel with back-feed circuit breakers. Two panel sections of the single split bus electrical panel may be selectively powered by a utility power source, a back-up photovoltaic power source, or a combination of the utility power source and the photovoltaic power source. A patch panel is associated with or a part of the split-bus electrical panel, which includes a plurality of wire termination locations, which facilitates making changes between a fully backed up system and a partially backed-up system. The patch panel is configured to enable an installer to selectively connect factory installed connections to the back-feed circuit breakers to either: (1) connect each panel section directly to utility power for full utility power to both panel sections; (2) alternately to connect the second panel section to the utility power via a microgrid interconnection device when the second panel section is presently at least partially powered by back-up photovoltaic power, or (3) alternately connect both panel sections to full back-up photovoltaic power. 
     The back-feed circuit breakers are arranged to allow connection of the microgrid interconnection device for isolation of a critical loads section from a standards loads section during back-up operation due to a utility power outage. The first panel section of the split-bus electrical panel may be selectively connected to a utility power source to supply power to non-critical standards loads. The second panel section of the split-bus electrical panel may be selectively connected to a photovoltaic power source to supply power to critical loads in a residence when there is a power outage. The second panel section may be selectively connected through a relay in the microgrid interconnection device to the utility power source, in parallel with the first panel section, to supply both utility power and photovoltaic power when there is no outage. The relay is configured to isolate the second panel when there is a utility power outage. 
     In accordance with one example embodiment described herein, an apparatus for providing full or partial back-up power of a residential photovoltaic system to power critical residential loads during a utility power outage, comprises: 
     a single, split-bus electrical panel including a first panel section of the split-bus electrical panel configured to supply power to non-critical standard electrical loads and a second panel section of the split-bus electrical panel configured to supply power to critical electrical loads by a back-up system, the critical loads required to be powered during a utility power outage; 
     a first circuit breaker in the first panel section connected to a first bus bar and a second bus bar of the first panel section, and connected to a first pair of wire terminations, the first circuit breaker configured to conduct power from a power source connected via the first pair of wire terminations; 
     a second circuit breaker in the second panel section connected to a first bus bar and a second bus bar of the second panel section, and connected to a second pair of wire terminations, the second circuit breaker configured to conduct power from a power source via the second pair of wire terminations; and 
     a power wiring patch panel associated with the split-bus electrical panel, including a plurality of wire termination locations interconnected by a plurality of factory installed connections in the patch panel, the patch panel configured to enable an installer to selectively connect the first and second pairs of wire terminations to selected wire termination locations of the patch panel to either: (1) connect each panel section directly to utility power for full utility power to both panel sections; (2) alternately to connect the second panel section to the utility power via a microgrid interconnection device when the second panel section is presently at least partially powered by back-up photovoltaic power, or (3) alternately connect both panel sections to full back-up photovoltaic power. 
     In accordance with one example embodiment described herein, the patch panel has a first wire termination location  1  connected to an L 1  phase of a split phase utility power source, and a second wire termination location  2  connected to an L 2  phase of the split phase utility power source; 
     wherein the patch panel is configured to connect the first wire termination location  1  to third  3  and fourth  11  wire termination locations and configured to connect the second wire termination location  2  to fifth  4  and sixth  12  wire termination locations; 
     wherein the patch panel is configured to connect an L 1  phase wire termination  109  of the first circuit breaker  110 A to the third wire termination location  3  of the patch panel and to connect an L 2  wire termination  111  of the first circuit breaker to the fifth wire termination location  4  of the patch panel, to conduct power from the utility power source to the first panel section  102 A; 
     wherein the patch panel is configured to connect an L 1  phase wire termination  113  of the second circuit breaker  110 B to a seventh wire termination location  6  of the patch panel and to connect an L 2  wire termination  115  of the second circuit breaker to an eighth wire termination location  8  of the patch panel; 
     wherein the patch panel is configured to connect the seventh wire termination location  6  to a ninth wire termination location  10  and to connect the eighth wire termination location  8  to a tenth wire termination location  9 ; 
     wherein the patch panel is configured to conduct power from the utility power source to the second panel section  102 B, by a first shorting wire  114 ′ between the fourth wire termination location  11  and the ninth wire termination location  10  of the patch panel, and by a second shorting wire  112 ′ between the sixth wire termination location  12  and the tenth wire termination location  9  of the patch panel, to connect each panel section to normal utility power, but without solar power back-up when there is a utility outage. 
     In accordance with one example embodiment described herein, the patch panel is configured to enable an installer to selectively connect the second panel section  102 B to the utility power via first and second relay switches A and B of a relay  118  in a microgrid interconnection device  116  when the second panel section is presently at least partially powered by back-up photovoltaic power, by enabling the installer to selectively remove the first and second shorting wires from the patch panel and enable the installer to connect a first relay switch A between the fourth wire termination  11  location and the ninth wire termination location  10  of the patch panel, and by enabling the installer to selectively connect a second relay B between the sixth wire termination location  12  and the tenth wire termination location  9  of the patch panel, for partial power back-up of the split-bus panel by powering the first panel section only with utility power and by powering the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. 
     In accordance with one example embodiment described herein, the first and second relay switches in the microgrid interconnection device are coupled to the utility power source and configured to be closed and conduct utility power from the utility power source when there is no utility power outage and to be open when there is a utility power outage. 
     In accordance with one example embodiment described herein, the patch panel is configured to connect an eleventh wire termination location  5  of the patch panel to the ninth wire termination location  10  and to connect a twelfth wire termination location  7  of the patch panel to the tenth wire termination location  9 ; 
     wherein the patch panel is configured to enable an installer to selectively move the L 1  phase wire termination  109  of the first circuit breaker  110 A from the third wire termination location  3  and to connect the L 1  phase wire termination  109  of the first circuit breaker  110 A to the eleventh wire termination location  5  of the patch panel and to move the L 2  wire termination  111  of the first circuit breaker from the fifth wire termination location  4  to the twelfth wire termination location  7  of the patch panel, to conduct power from the photovoltaic power source and from the utility power source to the first panel section  102 A, for full power back-up of the split-bus panel by powering both the first panel section and the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. 
     In accordance with one example embodiment described herein, the back-up system includes a back-up power source that includes a rechargeable battery, a charger, an inverter, and an outage detector that is configured to detect when there is a utility power outage and send an outage signal to the relay. 
     In accordance with one example embodiment described herein, an outage detector is associated with the microgrid connection device and is configured to detect whether there is a utility power outage and to cause a relay to open when a utility power outage is detected. 
     In accordance with one example embodiment described herein, system for providing full or partial back-up power of a residential photovoltaic system to power critical residential loads during a utility power outage, comprises: 
     a single, split-bus electrical panel including a first panel section of the split-bus electrical panel configured to supply power to non-critical standard electrical loads and a second panel section of the split-bus electrical panel configured to supply power to critical electrical loads by a back-up system, the critical loads required to be powered during a utility power outage; 
     a first circuit breaker in the first panel section connected to a first bus bar and a second bus bar of the first panel section, and connected to a first pair of wire terminations, the first circuit breaker configured to conduct power from a power source connected via the first pair of wire terminations; 
     a second circuit breaker in the second panel section connected to a first bus bar and a second bus bar of the second panel section, and connected to a second pair of wire terminations, the second circuit breaker configured to conduct power from a power source via the second pair of wire terminations; and 
     a power wiring patch panel associated with the split-bus electrical panel, including a plurality of wire termination locations interconnected by a plurality of factory installed connections in the patch panel, the patch panel configured to enable an installer to selectively connect the first and second wire terminations to selected wire termination locations of the patch panel to either: (1) connect each panel section directly to utility power for full utility power to both panel sections; (2) alternately to connect the second panel section to the utility power via a microgrid interconnection device when the second panel section is presently at least partially powered by back-up photovoltaic power, or (3) alternately connect both panel sections to full back-up photovoltaic power. 
     The resulting apparatus and system connect the two panel sections of the split bus in parallel, providing a convenient way for the installer implement either a partial back-up system or full back-up system at the time the home is being built, and moreover, to enable an electrician to later change the system, if desired by the home owner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed description of the disclosure, briefly summarized above, may be had by reference to various embodiments, some of which are illustrated in the appended drawings. While the appended drawings illustrate select embodiments of this disclosure, these drawings are not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is circuit and functional block diagram of a single split-bus electrical panel with back-feed circuit breakers protecting two sections of the single split bus electrical panel. The patch panel is shown as shipped from factory, which enables normal utility power and solar power without backup. 
         FIG.  2    is circuit and functional block diagram of  FIG.  1   , wherein the patch panel is configured for partial power back-up of the split-bus panel by powering the first panel section only with utility power and by powering the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. 
         FIG.  3 A  is a circuit and functional block diagram of  FIG.  1   , wherein the patch panel is configured for full power back-up of the split-bus panel by powering both the first panel section and the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. The figure shows the power flow from the relay of the microgrid interconnection device flowing to the first circuit breaker in the first panel section when there is no utility power outage. 
         FIG.  3 B  is circuit and functional block diagram of  FIG.  3 A , which shows the power flow from the second circuit breaker in the second panel flowing to the first circuit breaker in the first panel section when there is a utility power outage. 
         FIG.  3 C  is a circuit and functional block diagram of  FIG.  3 B , illustrating an alternate example embodiment of the single split-bus electrical panel  100 , wherein a back-up battery may provide back-up direct current to the solar inverter  134 , which is combined with the photoelectric direct current from the photovoltaic solar array  132 . 
         FIGS.  4 A to  4 D  depict a custom power distribution block with lugs serving as the patch panel. 
         FIGS.  5 A to  5 D  depict a power distribution block with lugs serving as the patch panel. 
     
    
    
     Identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. However, elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
       FIG.  1    illustrates an example of a single split-bus electrical panel  100  with back-feed circuit breakers  110 A and  110 B protecting two sections  102 A and  102 B of the single split bus electrical panel  100 , which are connected in parallel. The circuit breakers  110 A and  110 B are arranged to allow connection of a microgrid interconnection device (MID)  116  ( FIG.  2   ) for isolation of a critical loads section  108 B from a standard loads section  108 A during a back-up operation due to a utility power outage. The upper or second section  102 B is connected through a third back-feed circuit breaker  130  to a photovoltaic power source  132  ( FIG.  2   ). A patch panel  142  is associated with or is a part of the split-bus electrical panel  100 . The patch panel  142  includes a plurality of wire termination locations  1 - 12  interconnected by a plurality of factory pre-wired interconnection wires in the patch panel connected to back-feed circuit breakers  110 A and  110 B protecting the panel sections  102 A and  102 B. The patch panel is configured to connect first wire terminations  109  and  111  and second wire terminations  113  and  115  of the respective first and second circuit breakers 110 A and  110 B to wire termination locations  1 - 12  interconnected by a plurality of factory installed connections in the patch panel  142 , for powering the two panel sections  102 A and  102 B. 
     The single split-bus electrical panel apparatus  100  isolates critical electrical loads during a utility power outage, such as freezers, security systems, or electronic medical devices, to enable them to be powered by a renewable energy power source of a back-up system. The back-up system may be powered, for example, by at least one of a photovoltaic solar array  132  or a wind energy array. A first or lower panel section  102 A of the split-bus electrical panel  100  supplies power to the non-critical standard loads  108 A, such as general lighting, in a residence. A second or upper panel section  102 B of the split-bus electrical panel  100  supplies power to the critical loads  108 B in the residence, which must continue to be powered during a utility power outage. 
     In accordance with an example embodiment, a main incoming circuit breaker  103  is connected to an electric power utility that provides 120/240 VAC split phase electrical power for distribution by the split-bus electrical panel  100  to branch circuits of the residence. The utility supplies two 120 VAC phases L 1  and L 2  that are 180° out of phase with each other (split phases), and a grounded neutral voltage N. The main incoming circuit breaker  103  may be connected to the L 1  leg and the L 2  leg of the split-phase electrical power, and the grounded neutral voltage N may be connected to a neutral terminal of the split-bus electrical panel  100 . The main incoming circuit breaker  103  may have an example rating of 200 Amperes. 
     The first 120 VAC phase L 1  is between the L 1  leg and the grounded neutral N, the phase L 1  and is connected from the main breaker  103  via line  105  to a wire termination location  1  of patch panel  142  of the split-bus electrical panel  100 . The second 120 VAC phase L 2  is between the L 2  leg and the grounded Neutral N, the phase L 2  and is connected from the main breaker  103  via line  107  to a wire termination locations  2  of the patch panel  142 . A 240 VAC service may be available between the Leg L 1  and the Leg L 2  of the split-phase electrical power. 
     A first two-pole circuit breaker  110 A in the first panel section  102 A may be oriented as a back feed breaker to connect the L 1  bus bar  104 A to the L 1  phase of a power source and the L 2  bus bar  106 A to the phase L 2  of the power source, such as from the main circuit breaker  103 . The first two-pole circuit breaker  110 A may have an example rating of  110  Amperes. The first bus bar  104 A and the second bus bar  106 A in the first panel section  102 A, may each have an example bus bar rating of 225 Amperes. 
     A second two-pole circuit breaker  110 B in the second panel section  102 B may be oriented as a back feed breaker to connect the L 1  bus bar  104 B to the L 1  phase of a power source and the L 2  bus bar  106 B to the phase L 2  of the power source. The second two-pole circuit breaker  110 B may have an example rating of 110 Amperes. The first bus bar  104 B and the second bus bar  106 B in the second panel section  102 B, may each have an example bus bar rating of 225 Amperes. 
     A patch panel  142  is associated with or a part of the split-bus electrical panel  100 , which includes a plurality of wire termination locations  1 - 12 , which facilitates making changes between a fully backed up system and a partially backed-up system. The patch panel  142  is configured to connect wire terminations  109 ,  111 ,  113 , and  115  from the back-feed circuit breakers to the wire termination locations  1 - 12  of the patch panel to either: (1) connect each panel section  102 A and  102 B directly to utility power from the main breaker  103  for full utility power to both panel sections ( FIG.  1   ); (2) alternately to connect the second panel section  102 B to the utility power via a microgrid interconnection device  116  when the second panel section  102 B is presently at least partially powered by back-up photovoltaic power source  132  ( FIG.  2   ), or (3) alternately connect both panel sections  102 A and  102 B to full back-up photovoltaic power from back-up photovoltaic power source  132  ( FIGS.  3 A and  3 B ). 
     The patch panel is shipped from the factory to enable normal utility power and solar power without backup. The patch panel has a first wire termination location  1  connected to an L 1  phase of a split phase utility power source, and a second wire termination location  2  connected to an L 2  phase of the split phase utility power source. The patch panel is configured to connect the first wire termination location  1  to third  3  and fourth  11  wire termination locations and configured to connect the second wire termination location  2  to fifth  4  and sixth  12  wire termination locations. The patch panel is configured to connect an L 1  phase wire termination  109  of the first circuit breaker  110 A to the third wire termination location  3  of the patch panel and to connect an L 2  wire termination  111  of the first circuit breaker to the fifth wire termination location  4  of the patch panel, to conduct power from the utility power source to the first panel section  102 A. The patch panel is configured to connect an L 1  phase wire termination  113  of the second circuit breaker  110 B to a seventh wire termination location  6  of the patch panel and to connect an L 2  wire termination  115  of the second circuit breaker to an eighth wire termination location  8  of the patch panel. The patch panel is configured to connect the seventh wire termination location  6  to a ninth wire termination location  10  and to connect the eighth wire termination location  8  to a tenth wire termination location  9 . The patch panel is configured to conduct power from the utility power source to the second panel section  102 B, by a first shorting wire  114 ′ between the fourth wire termination location  11  and the ninth wire termination location  10  of the patch panel, and by a second shorting wire  112 ′ between the sixth wire termination location  12  and the tenth wire termination location  9  of the patch panel, to connect each panel section to normal utility power, but without solar power back-up when there is a utility outage. 
       FIG.  2    is circuit and functional block diagram of  FIG.  1   , wherein the patch panel is configured for partial power back-up of the split-bus panel by powering the first panel section  102 A only with utility power and by powering the second panel section  102 B with utility power that is backed up with photovoltaic power when there is a utility outage. In order to provide power to a home during a utility outage, even one that has a solar system, it is necessary to add not only a battery, but also a backup interface that is capable of detecting a utility outage and isolating the home from the utility grid so that the battery and solar inverter can then create a microgrid safely. The isolation is accomplished using a power relay able to meet the specifications of a Microgrid Interface Device according to UL standards and the National Electrical Code (NEC). 
     The patch panel is configured to enable an installer to selectively connect the second panel section  102 B to the utility power via first and second relay switches A and B of a relay  118  in a microgrid interconnection device  116  when the second panel section is presently at least partially powered by back-up photovoltaic power, by enabling the installer to selectively remove the first and second shorting wires from the patch panel. The patch panel is configured to enable the installer to connect a first relay switch A between the fourth wire termination  11  location and the ninth wire termination location  10  of the patch panel, and to selectively connect a second relay B between the sixth wire termination location  12  and the tenth wire termination location  9  of the patch panel. This configuration provides partial power back-up of the split-bus panel by powering the first panel section only with utility power and by powering the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. 
     The first and second relay switches A and B in the microgrid interconnection device  116  are coupled to the utility power source and configured to be closed and conduct utility power from the utility power source when there is no utility power outage and to be open when there is a utility power outage. 
       FIG.  3 A  is circuit and functional block diagram of  FIG.  1   , wherein the patch panel is configured for full power back-up of the split-bus panel by powering both the first panel section  102 A and the second panel section  102 B with utility power that is backed up with photovoltaic power when there is a utility outage. The figure shows the power flow from the relay  118  of the microgrid interconnection device  116  flowing to the first circuit breaker  110 A in the first panel section  102 A when there is no utility power outage. 
       FIG.  3 B  is circuit and functional block diagram of  FIG.  3 A , which shows the power flow from the second circuit breaker  110 B in the second panel  102 B flowing to the first circuit breaker  110 A in the first panel section  102 A when there is a utility power outage. 
     The patch panel is configured to connect an eleventh wire termination location  5  of the patch panel to the ninth wire termination location  10  and to connect a twelfth wire termination location  7  of the patch panel to the tenth wire termination location  9 . The patch panel is configured to enable an installer to selectively move the L 1  phase wire termination  109  of the first circuit breaker  110 A from the third wire termination location  3  and to connect the L 1  phase wire termination  109  of the first circuit breaker  110 A to the eleventh wire termination location  5  of the patch panel and to move the L 2  wire termination  111  of the first circuit breaker from the fifth wire termination location  4  to the twelfth wire termination location  7  of the patch panel, to conduct power from the photovoltaic power source and from the utility power source to the first panel section  102 A, for full power back-up of the split-bus panel by powering both the first panel section and the second panel section with utility power that is backed up with photovoltaic power when there is a utility outage. 
     The second panel section  102 B of the split-bus electrical panel  100  services a back-up system that includes renewable energy power sources such as at least one of a photovoltaic (PV) system or a wind energy system. The photovoltaic (PV) system with a battery back-up, includes a photovoltaic solar array  132 , a solar inverter  134 , and a back-up battery  120 . The back-up battery  120  includes a rechargeable battery, an inverter, a charger, and an outage detector  121 . In normal operation when there is no outage of power from the utility, the photovoltaic system with battery back-up supplements the utility power. 
     The solar inverter  134  receives direct current from the photovoltaic solar array  132  and outputs alternating current over lines  136  and  138  to a third two-pole circuit breaker  130  in the second panel section  102 B that may be oriented as a back feed breaker to connect the L 1  bus bar  104 B and the L 2  bus bar  106 B to the solar inverter  134 . The third two-pole circuit breaker  130  may have an example rating of 60 Amperes. The solar inverter  134  outputs the AC power to the L 1  bus bar  104 B and the L 2  bus bar  106 B in the second panel section  102 B via the third two-pole circuit breaker  130 . 
     The back-up battery  120  includes an inverter that converts direct current from the rechargeable battery and outputs alternating current to a fourth two-pole circuit breaker  124  in the second panel section  102 B that may be oriented as a back feed breaker to connect the L 1  bus bar  104 B and the L 2  bus bar  106 B to the inverter of the back-up battery  120 . The fourth two-pole circuit breaker  124  may have an example rating of 30 Amperes. The inverter of the back-up battery  120  outputs the AC power over lines  126  and  128  to the fourth two-pole breaker  124  and the L 1  bus bar  104 B and the L 2  bus bar  106 B in the second panel section  102 B, to supplement any insufficiency in photovoltaic power from the solar inverter  134 , if needed. In addition, the back-up battery  120  includes a rechargeable battery and a charger that receives the utility power (or solar power) from the fourth circuit breaker  124  to charge the rechargeable battery when there is no utility power outage. 
     The backup battery  120  includes an outage detector  121  that may be connected to either the L 1  phase or the L 2  phase outputs  105  and  107  from the main circuit breaker  103 . The outage detector  121  detects when the voltage changes in either or both of L 1  phase and L 2  phase outputs  105  and  107 , indicating an outage of utility power. In response, the outage detector  121  of the back-up battery  120  sends an outage signal  122  to the relay  118  in the microgrid interconnection device  116 , causing the relay  118  to open during the outage. When the relay  118  opens, the second panel section  102 B may become isolated from the main breaker  103 , so that the second panel  102 B may be powered only from the solar inverter  134  and the back-up battery  120 . This prevents solar power from leaking out through the main breaker  103  onto the utility grid, where it may cause a hazard to utility workers or others, who may come into contact with power lines of the grid. 
     Branch circuit breakers may, for example, be plugged into either the first L 1  bus bar  104 A or the second L 2  bus bar  106 A of the first panel section  102 A of the split-bus electrical panel  100 , to supply power to various non-critical standard loads  108 A of the residence. The first panel section  102 A of the split-bus electrical panel  100  has an interleaved type of bus connector arrangement with two columns of branch circuit breakers. Each branch circuit breaker originates on the opposite phase (L 1  or L 2 ) from the one above or below it. The 120 VAC branch circuit loads are connected between a breaker on phase L 1  bus bar  104 A and Neutral N or between a breaker on Phase L 2  bus bar  106 A and Neutral N. The 240 V branch circuit loads may be connected using a first single-pole breaker on Phase L 1  bus bar  104 A and a second single-pole breaker Phase L 2  bus bar  106 A. The branch circuit breakers may have example ratings in a range of 15 to 90 Amperes. 
     The branch circuit breakers may also, for example, be plugged into either the first L 1  bus bar  104 B or the second L 2  bus bar  106 B of the second panel section  102 B of the split-bus electrical panel  100 , to supply power to various critical loads  108 B of the residence. The second panel section  102 B of the split-bus electrical panel  100  has an interleaved type of bus connector arrangement with two columns of branch circuit breakers. Each branch circuit breaker originates on the opposite phase (L 1  or L 2 ) from the one above or below it. The 120 VAC branch circuit loads are connected between a breaker on phase L 1  bus bar  104 B and Neutral N or between a breaker on Phase L 2  bus bar  106 B and Neutral N. The 240 V branch circuit loads may be connected using a first single-pole breaker on Phase L 1  bus bar  104 B and a second single-pole breaker Phase L 2  bus bar  106 B. The branch circuit breakers may have example ratings in a range of 15 to 90 Amperes. 
     In this manner, power may be supplied to the critical loads  108 B connected to the second panel  102 B, which must continue to be powered during a utility power outage. 
     When the utility power outage ends and utility power resumes, the outage detector  121  in the back-up battery  120  detects that the voltage has returned to one or both of the L 1  phase and L 2  phase outputs  105  and  107  of the main breaker  103 , indicating that the outage of utility power has ended. In response, the outage detector  121  of the back-up battery  120  sends a signal that the outage has ended, to the relay  118  in the microgrid interconnection device  116 , causing the relay  118  to close. When the relay  118  closes, the second panel section  102 B may be reconnected to main breaker  103 , so that it may be powered by the utility power, as well as being powered by the supplementary power from the solar inverter  134  and the back-up battery  120 . 
       FIG.  3 C  is a circuit and functional block diagram of  FIG.  3 B , illustrating an alternate example embodiment of the single split-bus electrical panel  100 , wherein a back-up battery  120 ′ may provide back-up direct current over line  128 ′ to the solar inverter  134 , which is combined with the photoelectric direct current from the photovoltaic solar array  132 . The combined currents are converted by the solar inverter  134  to alternating current that is provided over lines  136  and  138  to the third circuit breaker  130 . In an alternate example embodiment, the outage detector  121 ′ may be associated with the microgrid connection device  116 . The outage detector is configured to detect whether there is a utility power outage and to cause the relay  118  to open when a utility power outage is detected. Battery power from the back-up battery is available to operate the relay  118  during a utility power outage. 
       FIGS.  4 A to  4 D  depict a custom power distribution block  404  with lugs  406  serving as the patch panel  142 . The custom power distribution block  404  is shown in  FIG.  4 A  as positioned in an electrical load center and connected between the main breaker  103  and the split bus panel  100 . The factory installed custom power distribution block  404  is mounted in a space allocated in the in the main load center or electrical panel of a home. The custom power distribution block  404  may be later connected to the microgrid interconnection device  116  and the relay  118  shown in  FIGS.  2 ,  3 A and  3 B , which may be later installed by an installer when converting the electrical system into a partially backed up or a fully backed up photovoltaic powered system. The custom power distribution block  404  shown in  FIG.  4 B  includes terminal lugs  406  that function as the patch panel  142 . The custom power distribution block  404  shown in  FIG.  4 C  identifies how the lugs  406  function as the wire termination locations  1  through  12  shown in the patch panel  142  depicted in  FIG.  4 D , and also depicted in  FIGS.  1 ,  2 ,  3 A, and  3 B . In the illustrated version of the custom power distribution block  404 , the multiple wire termination position lugs on the L 1  and L 2  outputs of the main breaker are also part of the patch panel. 
       FIGS.  5 A to  5 D  depict a power distribution block  408  with lugs  410  serving as the patch panel  142 . The power distribution block  408  is shown in  FIG.  5 A  as positioned in an electrical load center and connected between the main breaker  103  and the split bus panel  100 . The factory installed power distribution block  408  is mounted in a space allocated in the in the main load center or electrical panel of a home. The power distribution block  408  may be later connected to the microgrid interconnection device  116  and the relay  118  shown in  FIGS.  2 ,  3 A  and  3 B, which may be later installed by an installer when converting the electrical system into a partially backed up or a fully backed up photovoltaic powered system. The power distribution block  408  shown in  FIG.  5 B  includes terminal lugs  410  that function as the patch panel  142 . The power distribution block  408  shown in  FIG.  5 C  identifies how the lugs  410  function as the wire termination locations  1  through  12  shown in the patch panel  142  depicted in  FIG.  5 D , and also depicted in  FIGS.  1 ,  2 ,  3 A, and  3 B . 
     The resulting apparatus, system, and method connect the two panel sections of the split bus in parallel, providing a convenient way for the installer implement either a partial back-up system or full back-up system at the time the home is being built, and moreover, to enable an electrician to later change the system, if desired by the home owner. 
     In the preceding, reference is made to various embodiments. However, the scope of the present disclosure is not limited to the specific described embodiments. Instead, any combination of the described features and elements, whether related to different embodiments or not, is contemplated to implement and practice contemplated embodiments. Furthermore, although embodiments may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the scope of the present disclosure. Thus, the preceding aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other implementation examples are apparent upon reading and understanding the above description. Although the disclosure describes specific examples, it is recognized that the systems and methods of the disclosure are not limited to the examples described herein but may be practiced with modifications within the scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.