Patent Publication Number: US-11646571-B2

Title: Compact modular electrical load management system

Description:
RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application Ser. No. 62/924,555 (entitled Compact Modular Electrical Load Management System, filed Oct. 22, 2019) which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The importance of distributed energy generation, storage, and management is increasing rapidly, due to cost and performance advances in solar energy and battery technologies as well as customer demand for secure clean power systems. Dynamic pricing and Demand Response programs provide incentives to curtail or time-shift large loads to save money. Home automation technology enables active management of circuits or individual loads. Load management is particularly valuable to owners of battery energy storage systems because battery systems have limited power and energy storage capacity. Customers want the ability to manage onsite loads—for example to prevent the operation of low-priority loads, to prevent multiple large loads from operating simultaneously, or to time-shift large loads to take advantage of dynamic electric rates or the availability of solar energy. 
     Commercialized and announced load management products offer some of these capabilities, but the offerings are expensive, complex, and often require significant disruption to the existing electrical infrastructure of the building. 
       FIG.  1    is a prior art block diagram that illustrates components of a photovoltaic system with a battery energy storage system with a critical loads panel. This approach offers only two priority levels, and no flexibility to adjust which circuits are high priority after installation. It also requires a special inverter with a disconnect switch and re-routing of circuits. 
       FIG.  2    is a prior art diagram illustrating a smart breaker that requires a special breaker panel and is very expensive. 
       FIG.  3    is a prior art diagram illustrating a smart breaker that requires removal and replacement of an entire main panel. 
       FIG.  4    is a prior art diagram illustrating a smart breaker that requires an extra box and wiring in and out of a panel. 
     SUMMARY 
     A modular load management system comprises one or more compact modules designed to fit in the wiring troughs of a standard AC distribution panel of a building. The modules include one or more input terminals to receive electrical power from one or more circuit breakers in the panel and deliver power to load circuits of the building via one or more output terminals. The modules contain at least one disconnect switch for disconnecting circuits from breakers in response to a remote or locally generated control signal. The modules may also include current sensors on some or all terminals, such that power and energy flow may be monitored on a per-circuit basis. 
     The modules may be configured to connect end-to-end or via jumper cables to manage some or all of the circuits in the panel. One or more modules may contain a microprocessor, communications interface, or other means of implementing home energy management functionality via local or remote cloud-based control. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a prior art block diagram that illustrates a battery energy storage system with a critical loads panel. 
         FIG.  2    is a prior art diagram illustrating a smart breaker that requires a special breaker panel and is very expensive. 
         FIG.  3    is a prior art diagram illustrating a smart breaker that requires removal and replacement of an entire main panel. 
         FIG.  4    is a prior art diagram illustrating a smart breaker that requires an extra box and wiring in and out of a panel. 
         FIG.  5    is a block diagram illustrating a the basic configuration of a compact modular load management system (LMS) according to an example embodiment. 
         FIG.  6    is a block perspective view illustrating a load management unit (LMU) according to an example embodiment. 
         FIG.  7    is a block diagram illustrating a head unit with daisy chain connected LMU nodes according to an example embodiment. 
         FIG.  8    is a block diagram of an LMS node according to an example embodiment. 
         FIG.  9    is a block diagram of a system that includes a smart disconnect switch according to an example embodiment. 
         FIG.  10    is a screen shot of an overload protection user interface on a mobile device according to an example embodiment. 
         FIGS.  11    shows screen shots of a user interface illustrating loads that will be automatically shed in the event of an outage to extend battery life according to an example embodiment. 
         FIG.  12 A,  12 B,  12 C, and  12 D  show multiple views of the output terminal  236  that can accept wires from opposing directions according to an example embodiment. 
         FIGS.  13    illustrates wiring coupled to the terminal of  FIG.  12    according to an example embodiment. 
         FIGS.  14    illustrates wiring coupled to the terminal of  FIG.  12    according to an example embodiment. 
         FIGS.  15 A and  15 B  illustrate the difference in wiring when using the angled connectors on the left, and a standard connector on the right side according to an example embodiment. 
         FIG.  16    illustrates multiple nodes daisy chained together according to an example embodiment. 
         FIG.  17    illustrates an LMU node with an adjustable mount according to an example embodiment. 
         FIG.  18    illustrates an LMU node with an adjustable mount with the LMU node spaced from a base of the mount according to an example embodiment. 
         FIG.  19    is a block schematic diagram of a computer system to implement one or more example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized, and that structural, logical and electrical changes may be made without departing from the scope of the present invention. The following description of example embodiments is, therefore, not to be taken in a limited sense, and the scope of the present invention is defined by the appended claims. 
     The functions or algorithms described herein may be implemented in software in one embodiment. The software may consist of computer executable instructions stored on computer readable media or computer readable storage device such as one or more non-transitory memories or other type of hardware-based storage devices, either local or networked. Further, such functions correspond to modules, which may be software, hardware, firmware or any combination thereof. Multiple functions may be performed in one or more modules as desired, and the embodiments described are merely examples. The software may be executed on a digital signal processor, ASIC, microprocessor, or other type of processor operating on a computer system, such as a personal computer, server or other computer system, turning such computer system into a specifically programmed machine. 
     The functionality can be configured to perform an operation using, for instance, software, hardware, firmware, or the like. For example, the phrase “configured to” can refer to a logic circuit structure of a hardware element that is to implement the associated functionality. The phrase “configured to” can also refer to a logic circuit structure of a hardware element that is to implement the coding design of associated functionality of firmware or software. The term “module” refers to a structural element that can be implemented using any suitable hardware (e.g., a processor, among others), software (e.g., an application, among others), firmware, or any combination of hardware, software, and firmware. The term, “logic” encompasses any functionality for performing a task. For instance, each operation illustrated in the flowcharts corresponds to logic for performing that operation. An operation can be performed using, software, hardware, firmware, or the like. The terms, “component,” “system,” and the like may refer to computer-related entities, hardware, and software in execution, firmware, or combination thereof. A component may be a process running on a processor, an object, an executable, a program, a function, a subroutine, a computer, or a combination of software and hardware. The term, “processor,” may refer to a hardware component, such as a processing unit of a computer system. 
     Furthermore, the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard programming and engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computing device to implement the disclosed subject matter. The term, “article of manufacture,” as used herein is intended to encompass a computer program accessible from any computer-readable storage device or media. Computer-readable storage media can include, but are not limited to, magnetic storage devices, e.g., hard disk, floppy disk, magnetic strips, optical disk, compact disk (CD), digital versatile disk (DVD), smart cards, flash memory devices, among others. In contrast, computer-readable media, i.e., not storage media, may additionally include communication media such as transmission media for wireless signals and the like. 
       FIG.  5    illustrates the basic configuration of a compact modular load management system (LMS)  200 . A circuit panel  201  contains two rows of breakers  201 ,  202  etc., which may be part of an existing electrical system in a home or business. Load circuit breakers  210 ,  211  etc. conduct current to the various electrical needs of the building. The LMS comprises an LMS head unit  220 , at least one compact modular Load Management Units (LMU)  230 ,  231  etc., and signal-level cabling  240 ,  241 ,  242 , etc. to connect the LMS head unit  220  to a first LMU  230 , and thence to subsequent LMUs  231 ,  232  in a daisy-chain fashion. There are two connectors  250 ,  251  on the head unit  220 , one on the left, one on the right. This allows a daisy connection per row of breakers for neater cabling within the panel. An antenna  260  is attached directly to the head unit  220  via an antenna mount, with an option for an extension cable so antenna can be mounted on a knockout of panel for better wireless connectivity. Power connection  270  is located on the head unit  220  to power the entire system. 
     The LMS  200  in one embodiment is designed to fit within a wiring trough of a common electrical AC distribution panel  201 . Note that the LMUs  230 ,  231 ,  232  may be connect directly to the inside of the panel on the same sheet metal to which the breakers  210 ,  211  are attached. This may be done by the use of self-tapping screws in one embodiment. Further methods of attachment are illustrated below. 
       FIG.  6    is a block perspective view illustrating an LMU  230 . Each LMU  230  comprises at least one input lead  232 , positioned and spaced to align to the output terminals of the breakers in the panel, an internal relay or other switch  233 , internal current and voltage sensing  234 , a logic control circuit  235 , and one or more output terminals  236 , all housed in a durable, compact enclosure  237 . An optional mounting plate  238  facilitates securing the LMU to the interior of the breaker panel. On one side that is visible in  FIG.  6   , a tube  239  allows access via screwdriver or long screw to the plate  238  or directly to the back of the panel for securing the node to the panel. 
     To install the LMU  230 : 
     Step 1—Turn off the main breaker, open the front panel cover exposing the internal wirings. 
     Steps 2-4 illustrate the installation steps for the LMS head unit  220 . 
     Step 2—Mount the LMS head unit  220  to an empty spot near the top or bottom of the panel with self-tapping screws directly onto the rear metal surface of the panel. 
     Step 3—Connect the power cable to the LMS head unit  220 , the other end of the power cable should be connected to the appropriate phase A, phase B, and Neutral within the panel. 
     Step 4—Assemble antenna cable assembly may be done by securing the antenna  260  onto the antenna mount. Attach the antenna cable to the LMS head unit  220  and insert antenna mount through a free circular knockout opening. 
     Steps 5-10 illustrate the installation steps for the LMU  230 . 
     Step 5—Locate the circuit breaker  210 ,  211  intended for the installation, remove any existing wiring connections to the breaker. 
     Step 6—Secure the mounting plate  238  to the rear metal surface of the panel in-line with the breaker, leave a 10-20 mm distance to the breaker. 
     Step 7—Feed the LMU breaker side wires into the circuit breaker screw terminals. 
     Step 8—Clip LMU into the mounting plate and adjust to the appropriate height. 
     Step 9—Trim the existing wires from step 5 and feed them into the LMU screw terminals. 
     Step 10—Connect the LMU to the LMS head unit with the included cable. 
       FIG.  7    is a block diagram illustrating an LMU head unit  320  with daisy chain connected LMU nodes  330 ,  331 , and  332 . The head unit  320  comprises a data processor unit  321  such as a microprocessor, a communication module  322  that communicates with a local or remote information processing system (for instance via cellular, WiFi, ethernet, zigbee, etc.), a first node connection port  323  for communicating with LMUs  330 ,  331  (for example via RS485, CANbus, etc), and a power supply  324 , which may also measure voltage, frequency, or other power signals. A first signal-level cable  340  communicates two-way data and signal-level power to load management unit  330 ,  331 . A second node connection port  323  communicates with LMU  332  via second cable  340 . 
     This is the default configuration. There is an optional configuration where a smart disconnect switch (SDS) replaces the head unit  320 . See  FIG.  9   . LMUs will either connect to a head unit  320  or to the SDS. The head unit means the system is a stand-alone system, whereas with the SDS, the system may be a piece of a bigger unit. 
       FIG.  8    is a block diagram of an LMS node  800 . The LMU comprises of 1 or more load channels  380 ,  381 , an energy calculation block  361 , a micro-control unit (MCU)  370  and two node connections  351 ,  352  for communication with the head unit or smart disconnect switch (SDS) or other LMUs. Each load channel includes input terminals  332 , a current sensor  234 , a load switch  333  and an output terminal. For a single pole breaker, an LMS node  800  may be used with only one input  332 , current sensor  234 , switch  333 , and output  336 . It may be cost effective to group multiple load channels  380 ,  381  into one LMU, such as the two illustrated at the two strings of elements: input terminal  232 , current sensor  234 , switch  233 , and output  236 . In further embodiments, up to ten or so load channels may be accommodated in one LMU. 
     Load switches  333  may be mechanical switches such as electromechanical relays, or alternatively silicon-based switches, configured to close or break the flow of current between input terminals  332  and output terminals  336 . Current sensors  234  configured to measure the current in each circuit may be resistive shunt-type sensors, hall-effect sensors, or other sensing technologies. An Energy Measurement IC or ADC  361  may be used to process the data by performing energy calculations before transferring to the MCU  370 . Node connections  351 ,  352  are configured to send and receive signals from the head unit or SDS (such as the current measurements in the LMU) and control the power switches according to commands from the head unit/SDS or configurable parameters set within the LMU. There are two node connections on each device (node or head/SDS) to facilitate daisy chaining connections between devices. All node connections are linked to the same power and data bus. 
     In operation, on power-up the head unit data processor may perform system checks on the connected components, and then sets the condition of the load switches based on pre-defined defaults (for instance, the system may be configured to default to closed switches for a grid-connected system and open switches for an off-grid system. The head unit then attempts to establish communication to provide remote control of this system to the user or automated processes. 
     The switch may be configured to open dynamically based on droop in voltage or frequency below a threshold. For example, when frequency drops below 59 Hz, the switch will open, disconnecting the load. There are many other reasons for opening and closing the switches. In a situation where a Home has a backup battery, the system can see how much power the Home is using and disconnect certain loads to make sure the battery is not overloaded when switching from Grid to Battery power. When the grid is down and the Home is being powered by battery, disconnecting specific loads can extend life of the battery. In one embodiment, the largest loads in the home may be cut in response to one or more of the above reasons, such as Pool pumps, Water heaters and Air conditioners. Variations in the voltage can come from surges or noise on the line. For frequency, if the Home includes a generator, there may be some issues syncing together. 
     The system may also be designed to open and close based on command from an inverter, SDS, or other local master, default to closed unless remote command (e.g. utility DR), operate in a cyclic lockout mode to enable several large loads to run in sequence, operate based on a hierarchical nested set of rules, and open and close based on battery saving profiles set by the user or AI. 
     In a situation where the Home has a backup battery, the system can see how much power the Home is using and disconnect certain loads to make sure the battery is not overloaded when switching from Grid to Battery power. 
     When the grid is down and home is being powered by battery, disconnecting specific loads can extend the life of battery. For example, disconnecting large loads such as pool pumps and water heaters may extend battery by a few hours. 
       FIG.  9    is a block diagram of a system  900  that includes a smart disconnect switch (SDS)  910 . This is an optional configuration where the SDS  910  replaces the head unit. 
     In some embodiments the LMUs may be connected to an internal or external disconnect switch or transfer switch via digital communication as described above. In this case a data processing unit  915  within the disconnect switch  910  may process signals from the LMUs and command operation of the individual circuit switches. The SMU  910  may include an energy measurement unit  920 , wireless communications unit  925 , disconnect switch  930 , and node connection port  935  for coupling to one more nodes  940 ,  945 , and  950 . 
     In some embodiments, an elongated LMU may include 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more circuits. The head unit may include ports for main service CTs. A single LMU may connect and control multiple circuit breakers. 
     The com cable in some embodiments may carry neutral, allowing the units to self-power and operate autonomously. 
     An LMU with no signal from the head unit can make autonomous decisions to switch the relay depending on different scenarios such as failure modes and overcurrent detection. 
     In one embodiment, DIP switches on the top surface of the LMU allows On/Off/Remote functions, providing a physical override. 
     Overload Protection: 
     Scenario—When a grid outage occurs, and a battery will become the primary source of power for the home delivered through the circuit breaker panel and LMUs. The LMUs may process data representative of sensed current via the LMU current sensors and process the data to provide energy utilization information. The energy utilization information may be transmitted via the communication circuitry and antenna to one or more user devices, either directly or via one or more intermediate servers which may further process the information. 
     The load management system can detect how much current power is required to power the home and see how much power the battery can provide. With this information, the LMS will take action and disconnect loads utilizing the LMU disconnect switches based on a predefined priority to prevent the battery from being overloaded. 
       FIG.  10    is a screen shot  1000  of an overload protection user interface on a mobile device. Battery Life Optimization: 
     Scenario—After an outage and Overload protection has stabilized the home energy consumption. The system will allow the user to select which loads to shed to increase battery life by displaying the loads via mobile device display with user interface selection mechanisms, such as checkboxes or highlighting, for selection of loads to shed. In one embodiment, an icon  1010  represents loads that will be automatically switched off in the event of a power outage. The loads with icon  1010  includes the dishwasher, clothes dryer, electric vehicle charger, and pool pump. Colored buttons  1020  for each load in the list illustrate which loads are currently drawing power such as via a green color, with a red color indicating the load is currently not drawing power. 
     The mobile device display may also include current battery power available at  1030  and a total current energy utilization  1040  for the Home. 
       FIG.  11    shows screen shots  1100 ,  1110  of a user interface illustrating battery optimization selections, basic  1115 , comfort  1120 , and luxury  1125  selections. The load management system can calculate how long the home can run off the battery. Time remaining for the current selection, comfort  1120 , is illustrated. A list of loads is also displayed and may be turned off via touch screen switch as shown at  1130 . Screen shot  1100  shows four loads, all switched on with a corresponding remaining battery time of 3 hours 32 minutes. Screen shot  1200  shows the same four loads with the first two loads, sump pump and water heater turned off, resulting in a remaining battery time of 7 hours 25 minutes. Thus the user interface allows users to both select a level of comfort, as well as loads to turn on or off in each selected level, balancing life style desires with remaining battery life during grid or other power supply outages. 
       FIGS.  12 A,  12 B,  12 C, and  12 C  shows multiple views, top, side, perspective, and end views, of the output terminal  236  that can accept wires from opposing directions. The custom designed terminal can accept wires from opposing directions, allowing the product to be installed in panels where home wiring can enter from the top or the bottom. The pair of approximately 45-degree entry points (openings on two separate planes that are at a right angle to each other and each being at 45 degree angles from a surface to which the terminal is attached) of the terminal  236  reduces the wire bending radius providing greater flexibility than a single orthogonal entry point. Other entry point angles may be used in further embodiments to reduce wire bending radius may be used. From the figures below, the entry point to the terminal is 45 degrees instead of requiring a full 90-degree turn. This would reduce the required wire bending radius significantly. 
       FIGS.  13 ,  14 ,  15 A, and  15 B  illustrate wiring coupled to the terminal  236  of  FIG.  12   . The architecture of this product requires one head unit which includes the central processing unit and the wireless connectivity. The head unit is capable of connecting to 20+ node units and communicate through RS485. This feature allows users to connect node units to fulfill their home configuration. Different flavor nodes (switch current capability, size, single pole, dual pole) may be selected that fit requirements. The node units can be daisy chained together so it&#39;s not a requirement for node units to connect directly to the head. Daisy chaining allows for cleaner and simpler wiring within the breaker panel. Daisy-chaining further allows for the smallest form-factor for each atomic unit, optimizing panel fit &amp; therefore compatibility. 
       FIG.  15 A and  15 B  illustrate the difference in wiring when using the angled connector  236  and a standard connector  1500  respectively. Note that more lateral space away from the connector is required for the standard connector  1500 , whereas the angled connector  236  facilitates the use of less lateral space to run the wiring orthogonal to the connector  236  and up or down the panel to the load. The use of the angled connectors  236  facilitates fitting more LMUs into a panel and more flexibility in wiring, as more LMUs may be placed closer to breakers and leave more room on lateral sides of the panel for wiring. 
     The angled connectors  236  include two connectors that are arranged at approximately 90-degree angles from each other to reduce the curvature of coupled wiring within the circuit breaker panel to one or more loads. In some embodiments, the connectors may be angled between 80 degrees and 100 degrees. In some embodiments, the connectors may be angled between 60 degrees and 120 degrees. Other angles less than 180 degrees that provide the benefit of reduce radius of curvature of wiring may be used in further embodiments 
       FIG.  16    illustrates multiple nodes  1600  daisy chained together. Autonomous Overload Protection: In one embodiment the disconnect switch is activated automatically based on conditions in the home&#39;s electricity network so as to protect site-level generation equipment. Examples of such equipment include, without limitation, reciprocating engine generators, photovoltaic systems, and battery systems. 
       FIGS.  17  and  18    illustrate an LMU node with an adjustable mount.  FIG.  17    is a perspective view of LMU node  1700 .  FIG.  18    is a perspective view of the node  1700  in a different position. A mount  1710  may be screwed or otherwise attached by glue or other means for fastening the node to the inside back of an electrical distribution panel. Tabs  1720  extending out from a base of the mount may be used to couple the LMU node at various heights above the base of the mount  1700 . Note the notches  1800  in the LMU node side that are designed to mate with a protrusion (not shown) on the node facing sides of the tabs  1720  to secure the node a desired height above the base of the mount. Such mounting allows potentially dense wiring in the panel to be routed between the tabs and between the base of the mount and the bottom of the node. 
       FIG.  19    is a block schematic diagram of a computer system  1900  to implement devices and control circuitry to perform methods and algorithms according to example embodiments. All components need not be used in various embodiments. 
     One example computing device in the form of a computer  1900  may include a processing unit  1902 , memory  1903 , removable storage  1910 , and non-removable storage  1912 . Although the example computing device is illustrated and described as computer  1900 , the computing device may be in different forms in different embodiments. For example, the computing device may instead be a smartphone, a tablet, smartwatch, smart storage device (SSD), or other computing device including the same or similar elements as illustrated and described with regard to  FIG.  19   . Devices, such as smartphones, tablets, and smartwatches, are generally collectively referred to as mobile devices or user equipment. 
     Although the various data storage elements are illustrated as part of the computer  1900 , the storage may also or alternatively include cloud-based storage accessible via a network, such as the Internet or server-based storage. Note also that an SSD may include a processor on which the parser may be run, allowing transfer of parsed, filtered data through I/O channels between the SSD and main memory. 
     Memory  1903  may include volatile memory  1914  and non-volatile memory  1908 . Computer  1900  may include—or have access to a computing environment that includes—a variety of computer-readable media, such as volatile memory  1914  and non-volatile memory  1908 , removable storage  1910  and non-removable storage  1912 . Computer storage includes random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM) or electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD ROM), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium capable of storing computer-readable instructions. 
     Computer  1900  may include or have access to a computing environment that includes input interface  1906 , output interface  1904 , and a communication interface  1916 . Output interface  1904  may include a display device, such as a touchscreen, that also may serve as an input device. The input interface  1906  may include one or more of a touchscreen, touchpad, mouse, keyboard, camera, one or more device-specific buttons, one or more sensors integrated within or coupled via wired or wireless data connections to the computer  1900 , and other input devices. The computer may operate in a networked environment using a communication connection to connect to one or more remote computers, such as database servers. The remote computer may include a personal computer (PC), server, router, network PC, a peer device or other common data flow network switch, or the like. The communication connection may include a Local Area Network (LAN), a Wide Area Network (WAN), cellular, Wi-Fi, Bluetooth, or other networks. According to one embodiment, the various components of computer  1900  are connected with a system bus  1920 . 
     Computer-readable instructions stored on a computer-readable medium are executable by the processing unit  1902  of the computer  1900 , such as a program  1918 . The program  1918  in some embodiments comprises software to implement one or control algorithms described herein. A hard drive, CD-ROM, and RAM are some examples of articles including a non-transitory computer-readable medium such as a storage device. The terms computer-readable medium and storage device do not include carrier waves to the extent carrier waves are deemed too transitory. Storage can also include networked storage, such as a storage area network (SAN). Computer program  1918  along with the workspace manager  1922  may be used to cause processing unit  1902  to perform one or more methods or algorithms described herein. 
     EXAMPLES 
     A modular load management system comprising
         a. One or more compact load management modules comprising   i. One or more input terminals   ii. One or more output terminals   iii. One or more switches connected between input and output terminals,   iv. One or more communication ports   b. Where the load management modules are configured to fit inside the wiring chase of an existing circuit panel       

     Autonomous Overload Protection. An embodiment of any of the above examples wherein the disconnect switch is activated automatically based on conditions in the home&#39;s electricity network so as to protect site-level generation equipment. Examples of such equipment include, without limitation, reciprocating engine generators, photovoltaic systems, and battery systems. 
     An embodiment wherein the triggers for automatic activation include, without limitation, AC power frequency conditions, AC power voltage conditions, and circuit-level load conditions. 
     An embodiment wherein distinct setpoints for trigger conditions can be configured so as to establish priority of which loads are disconnected first during an overload protection event. 
     An embodiment wherein a ‘dead-man&#39;s switch’ or watchdog mechanism is employed to ensure that the state of the switch in each LMU is ‘connected’ whenever communication with the head node is lost. 
     An embodiment wherein energy consumed by the circuit is accumulated over time and such information is protected from loss/rollback by detecting immanent power outages and saving data to non-volatile memory prior to complete power loss has occurred. 
     An embodiment wherein a commissioning tool or application is used to record which loads/circuits a given relay will be connected to prior to installation. 
     A device will switch relays when virtually no current is flowing through using zero crossing detection. This reduces wear on the components, prevent arcing between contacts of the switch, reduce noise. 
     Nodes may be interconnected with expandable coil-like cables to adapt to different lengths. This will reduce the number of cables in the panel. 
     Nodes may be secured to the inside of the panel with a height-adjustable mount, this will allow ease of install for varying breaker wire entry heights. 
     A head device may connect to the nodes stated above and also unique modules such as metering-only nodes, hot water heater control and lighting dimmers. 
     Nodes can be software-configured to act as a dual-pole switch for split-phase 240V applications, or two single-pole switches for 120V applications. 
     Although a few embodiments have been described in detail above, other modifications are possible. For example, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Other embodiments may be within the scope of the following claims.