Abstract:
A panelboard configured for distributing electricity from a power source, the panelboard comprising circuitry for distributing the electricity from the power source, the circuitry comprising a plurality of branch circuits for distributing electricity to associated loads; a plurality of branch circuit breakers, each branch circuit breaker intermediate the power source and the plurality of branch circuits; and an electronic control module for controlling the main circuit breaker and the plurality of branch circuit breakers, the electronic control module provides a protection function and a monitoring function of the circuitry, each branch circuit breaker of the plurality of branch circuit breakers includes; a pair of separable contacts, an electromagnetic actuator in electrical communication with the electronic control module for operably controlling the pair of separable contacts, and a current transformer configured to sense current on the circuitry to one of the associated loads. A method is also described for providing overcurrent protection and control to an electric circuit with a single controller, the method comprising: receiving a trip setting value selected for each branch circuit of a plurality of branch circuits; storing the trip setting value in non-volatile memory; receiving a plurality of sensed signals from a current sensing device employed in the each branch circuit indicating a current therethrough; processing the plurality of sensed signals to detect an overcurrent condition in the each branch circuit; and generating a trip signal to an electromagnetic device coupled to separable contacts employed in each circuit breaker of the each branch circuit for interrupting current therein when an overcurrent condition is detected.

Description:
BACKGROUND OF INVENTION  
         [0001]    An electrical distribution system within an industrial, commercial or residential property starts at the utility service entrance and ends at the final utilization equipment or loads. The service entrance includes the utility company&#39;s wattmeter or kWh meter. Beyond the utility company&#39;s meter is a main circuit interrupting device, such as a circuit breaker. The main circuit breaker supplies power to a number of feeder circuits which in turn power a number of branch circuits. In a small system, such as a home, the main circuits directly feed individual branch circuits and no feeder circuits are employed. The electrical utilization loads are normally located on the branch circuits.  
           [0002]    Typically, circuit breakers are used on the branch circuits to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit condition. Circuit breakers employed in a commercial or residential setting are mounted in the panelboard. In residential or low ampacity circuit breakers, the circuit breakers are typically calibrated to a specific current value and with a specific trip time curve.  
           [0003]    In contrast, industrial circuit breakers have used the concept of rating plugs with electronic trip units for many years to set the current ratings thereof. By inserting a rating plug, having a discrete resistance value, into a circuit breaker trip unit, the current rating is set for the industrial circuit breaker. Residential circuit breakers do not have the size or cost structure to accept rating plugs and consequently, residential circuit breakers are for practical purposes limited to a predetermined current rating.  
           [0004]    Consequently, residential low ampacity circuit breakers have traditionally used the older thermal magnetic technology which does not have ready methods for changing the current rating of the circuit breaker. The thermal trip characteristic is operative in response to overload current of extended duration which heats a bimetal member, causing movement of the latter, which in turn releases a latch to trip open a set of contacts. The magnetic characteristic is operative in response to a sudden high magnitude current overload condition, and uses the magnetic field generated in a magnetic core to attract typically an armature, which movement releases the latch to open the contacts. As an example, the magnetic type actuation occurs in response to a short circuit wherein the hot line conductor becomes directly connected with ground or neutral, bypassing the load.  
           [0005]    In either an industrial or residential environment, it is important to provide a management system which facilitates the monitoring and accurate control of electricity. The evolution and resulting dependency on digital computers and communication networks connecting these computers, such as data processing centers, has created a demand for high accuracy low ampacity circuit breakers to protect such critical load applications in branch circuits. Furthermore, advanced monitoring and remote control traditionally found in large, expensive industrial circuit breakers is desired for residential and commercial low ampacity circuit breakers without a premium price and size penalty.  
           [0006]    It is known to employ electronic control, such as a computer, for controlling the solenoids of a plurality of circuit breakers in a panelboard. It is also known to employ the computer to monitor the status of the circuit breakers in a panelboard from the status contacts. What is needed is a low cost compact individual circuit breaker that allows for tailored protection to meet specific load requirements.  
         SUMMARY OF INVENTION  
         [0007]    The above discussed and other drawbacks and deficiencies are overcome or alleviated by a panelboard configured for distributing electricity from a power source. The panelboard comprises: circuitry for distributing the electricity from the power source, the circuitry comprising a plurality of branch circuits for distributing electricity to associated loads; a plurality of branch circuit breakers, each branch circuit breaker intermediate the power source and the plurality of branch circuits; and an electronic control module for controlling the main circuit breaker and the plurality of branch circuit breakers, the electronic control module provides a protection function and a monitoring function of the circuitry, each branch circuit breaker of the plurality of branch circuit breakers includes; a pair of separable contacts, an electromagnetic actuator in electrical communication with the electronic control module for operably controlling the pair of separable contacts, and a current transformer configured to sense current on the circuitry to one of the associated loads.  
           [0008]    A method is also described for providing overcurrent protection and control to an electric circuit with a single controller, the method comprising: receiving a trip setting value selected for each branch circuit of a plurality of branch circuits; storing the trip setting value in non-volatile memory; receiving a plurality of sensed signals from a current sensing device employed in the each branch circuit indicating a current therethrough; processing the plurality of sensed signals to detect an overcurrent condition in the each branch circuit; and generating a trip signal to an electromagnetic device coupled to separable contacts employed in each circuit breaker of the each branch circuit for interrupting current therein when an overcurrent condition is detected. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0009]    Referring to the drawings wherein like elements are numbered alike in the several Figures:  
         [0010]    [0010]FIG. 1 is a block diagram of a panelboard having a plurality of branch circuit breakers, a main circuit breaker, and a controller employed for overcurrent protection and monitoring;  
         [0011]    [0011]FIG. 2 is a schematic representation of the controller in communication with either the main circuit breaker or with one of the plurality of circuit breakers of FIG. 1;  
         [0012]    [0012]FIG. 3 is a front view of the panelboard shown in FIG. 1 illustrating partial section views of the panelboard having two branch circuit breakers employed therein; and  
         [0013]    [0013]FIG. 4 is a schematic side view of one of the branch circuit breakers of FIG. 3 in communication with the controller. 
     
    
     DETAILED DESCRIPTION  
       [0014]    Referring to FIG. 1, a panelboard  2  for alternating current (AC) power lines L 1 ,L 2 , neutral line N, and loads  4 , 6 , 8 , 10 , 12 , 14  is illustrated. The lines L 1 ,L 2 ,N supply voltage (e.g., conventional 120/240 VAC, single phase, three wire) to panelboard  2  through meter (M)  16 . Panelboard  2  includes a box or housing, such as an enclosure  18 , branch circuit breakers (CB)  20 , 22 , 24 , 26 , 28 , 30  housed by enclosure  18 , and an Electronic Overload Relay and Monitoring Module (EORMM) or controller  36  at least substantially within the enclosure  18 . Although two power lines and six branch circuit breakers are illustrated, it will be appreciated that a wide variety of power line and circuit breaker counts may be employed. The controller  36  communicates with each branch circuit breaker  20 , 22 , 24 , 26 , 28 , 30 , monitors (e.g., monitors each circuit breaker current through a current sensing transformer employed in each circuit breaker), and controls branch circuit breakers  20 , 22 , 24 , 26 , 28 , 30 , which are discussed below in connection with FIG. 2.  
         [0015]    In the exemplary embodiment of FIG. 1, panelboard  2  has one main circuit breaker (MAIN CB)  42  and a plurality of CBs  20 , 22 , 24 , 26 , 28 , 30 , with CBs  20 , 22 , 26 , 30  powered through MAIN CB  42  by line L 1 , and with CBs  24 , 28  powered through MAIN CB  42  by line L 2 . Each of the branch circuits  44 ,  52 ,  62 ,  46 ,  48 ,  49  is respectively powered through CB&#39;s  20 ,  22 ,  24 ,  28 ,  30 ,  26  and are each monitored for current. A computer  38  is connected to branch circuit  52  via electrical outlet  54 . In many critical uptime applications, (i.e., using computer  38 ), it is critical to monitor and control current in such a branch circuit to avoid an interruption caused by an overcurrent condition. For example, the output of a current transformer (CT) (not shown) located within branch circuit breaker  20  yields an output I 1 , indicative of the current in circuit  44 , which is fed to controller  36  via line  64 . The main circuit breaker  42  and each of the other branch circuits is similarly monitored by sensing the current with a CT employed in each circuit breaker and a corresponding signal indicative of current flow is fed to controller  36  via lines  63 ,  65 ,  66 ,  67 ,  68 ,  69 . Controller  36  processes the signals received from each line  63 , 64 , 65 , 66 , 67 , 68 , 69  to determine whether an overcurrent exists. If controller  36  detects an overcurrent condition in one or more CB, an actuation signal is outputted to one or more CBs via a control bus  70  to actuate the opening of contacts within the respective circuit breakers. In one embodiment, as in FIG. 2, an addressable device  101  is located in panelboard  2  and sends the actuation signal to a corresponding circuit breaker for actuation. In another embodiment, depicted in FIGS. 3 and 4, control bus  70  is substituted with a hard wired configuration for connection and actuation of each circuit breaker. In addition, it is contemplated that controller  36  optionally include a high current alarm, a breaker trip alarm, and/or remote communication control and monitoring for each circuit breaker employed in panel board  2 . Moreover, controller  36  may optionally include a neutral current transformer and a ground fault alarm or trip indicative of ground fault through main circuit breaker  42 . The high current alarm indicates a near overcurrent condition, thus allowing protective measures to be undertaken before the circuit is interrupted. Similarly, the breaker trip alarm provides notice of an interrupted circuit that may otherwise go undetected for some time. The ground fault alarm would provide notice of a potentially dangerous leakage of current.  
         [0016]    [0016]FIG. 2 is a schematic block diagram of controller  36  and one of either main circuit breaker  42  and branch circuit breakers  20 ,  22 ,  24 ,  26 ,  28 ,  30 , the controller generally shown at  36 . Although four circuit breakers are shown with controller  36 , it will be understood that a plurality of branch circuit breakers including a main circuit breaker is contemplated to be connected with controller  36 . Controller  36  receives an input signal from a current sensor  71  employed in each circuit breaker and provides an analog signal indicative of current measurements on a signal line  72 . The analog signal on line  72  is presented to a multiplexer or selector switch. 73 . Selector switch is controlled by a microprocessor or microcontroller  84  to select an input channel or multiple channels. The analog signal is presented to an A/D (analog/digital) converter  74 , which converts this analog signal to a digital signal. The digital signal is presented over a bus  80  to a microcontroller (signal processor)  84 , such being commercially available from Texas Instruments (e.g., Texas Instruments” TMS320 type processor). The digital signal is accumulated in memory corresponding to the input channel that was previously selected by the microcontroller  84  and output by the selector switch.  73 . Controller  36  further includes RAM (random access memory)  86 , ROM (read only memory)  88  and EEPROM (electronic erasable programmable read only memory)  90  all of which communicate with the microcontroller  84  over a control bus  92 . It will be appreciated that selector switch  73 , A/D converter  74 , ROM  88 , RAM  86 , or any combination thereof, may be internal to microcontroller  84 , as is well known. EEPROM  90  is non-volatile so that system information and programming will not be lost during a power interruption or outage. Data, typically status of the circuit breaker, is displayed by a display  94  in response to display signals received from microcontroller  84  over control bus  92 . An output control device  96 , in response to control signals received from microcontroller  84  over control bus  92 , controls a trip module  98  via signal line  76 . Trip module  98  processes the signal generated from microcontroller  84  to verify an overcurrent condition, and generates an actuation signal  99  via control bus  70  to an electromagnetic actuator, such as a solenoid  100  if an overcurrent condition is detected. Power supply  108  provides an actuation voltage  110  to trip module  98 , which in turn generates the actuation signal  99  to solenoid  100  that trips a mechanical operating mechanism  120 . Operating mechanism  120  in turn opens the circuit breaker contacts  130  that provide an electrical connection between the power line  132  and the load  134 . Power supply  108  and thereby controller  36  optionally receive electrical power generated from one or more current transformers  71  via line  136  to provide the electrical power necessary to operate controller  36 . Controller  36  may also use L 1 /L 2 , L 1 /N or L 2 /N voltages (See FIG. 1). This is possible, even with very small VA sources, because a magnet,  334 , is retained within circuit trip assembly  320  (See FIG. 4). In addition, the electrical power necessary to actuate solenoid  100  is optionally supplied by current transformer  71 .  
         [0017]    Microcontroller  84  processes signals received from a number of circuit breakers in panelboard  2  to determine whether an overcurrent condition exists in an individual or multiple branch circuits or in the main circuit. When an overcurrent condition exists, microcontroller  84  generates an output signal via signal line  76  received by trip module  98 . Trip module  98  generates an addressed actuation signal  99  to solenoid  100  of the respective circuit breaker(s) to cause operating mechanism  120  to trip the circuit breaker by opening the contacts  130 .  
         [0018]    Microcontroller  84  is disposed in controller  36  in communication with the main circuit breaker  42  and with the various branch circuit breakers of panelboard  2 .  
         [0019]    Microcontroller  84  receives informational signals from each of the current transformers  71  employed in each circuit breaker, quantifies the received information, and provides an output command signal in response thereto, in this instance, for example, to the trip module  98  addressing a particular solenoid  100  to be actuated through control bus  70  addressable device  101 . Communications, informational signals and commands as such may be employed by microcontroller  84  to facilitate execution of control processes and or algorithms including, but not limited to, setting trip points for individual circuit breakers, and/or the trip-time curve characteristic for each circuit breaker discussed herein.  
         [0020]    In order to perform the prescribed functions and desired processing, as well as the computations therefore (e.g., the execution of the trip-time curve algorithm(s), and the like), microcontroller  84  may include, but not be limited to, a processor(s), computer(s), memory, storage, register(s), timing, interrupt(s), communication interfaces, and input/output signal interfaces, and the like, as well as combinations comprising at least one of the foregoing. For example, microcontroller  84  may include signal input filtering to enable accurate sampling and conversion or acquisitions of such signals from communications interfaces.  
         [0021]    Referring now to FIG. 3, a front view of panelboard  2  shown in FIG. 1 illustrating partial section views of panelboard  2  having two branch circuit breakers  26 ,  30  employed therein is shown. Electrical conductors, L 1 , L 2 , and N terminals, are insulatively mounted along the length of panelboard  2 , such that they do not short with each other through contact with housing  18 . Main circuit breaker is electrically connected to both L 1  and L 2 . Controller  36  is disposed between main circuit breaker  42  and branch circuit breakers  20 ,  22 ,  24 ,  26 ,  30 . Controller  36  includes a control panel  150  for a user interface having three sections, a first section  160 , a second section  170 , and a third section  180 . First section  160  includes a first keypad  200  for selecting a branch circuit breaker to display and monitor an indication of the current flow therein. A first display  202  of display  94  indicates the current flow in a branch circuit breaker selected by keypad  200  or any breaker in alarm or overcurrent condition and indicates the branch circuit breaker selected. A third display  204  of display  94  indicates the current flow in main circuit breaker  42 . Second section  170  of control panel  150  indicates the status of a branch circuit breaker selected in first section  160  with first keypad  200 . A plurality of Light Emitting Diodes (LEDs)  208  is used having different colors to indicate the status of a particular branch circuit  48 ,  49 . For instance, an LED may be illuminated green to indicate a healthy circuit or may be illuminated yellow to warn of a potential overcurrent condition. An LED  208  may be illuminated red to indicate a tripped circuit. It is contemplated that controller  36  emits an audible alert or alarm when a branch circuit breaker has tripped and does not matter if that particular branch circuit is selected on control panel  150 . Data, typically status of the circuit breaker, is displayed by the display  94  in response to display signals received from microcontroller  84  over control bus  92  (see FIG. 2). The third section  180  includes a keypad  210  for inputting set point data and a display  212  of display  94  for indicating set points selected with keypad  210 .  
         [0022]    A communications port is an alternative input source to keypads  200  and  210 . Communications port  214  provides a remote means for inputting the long delay, short delay and instantaneous trip setting values to be stored in memory designated for each branch circuit breaker and main circuit breaker  42 . It should be noted that a trip setting value inputted via communications port  214  replaces the trip setting value previously stored in memory associated for that particular circuit breaker selected.  
         [0023]    The communications network interface  214  for remote digital input and monitoring includes, but is not limited to, one of or a combination of: a direct connection to a personal computer (PC)  216 , a dialup connection (e.g., Internet)  130 , or a local area network (LAN)  218  connecting a number of remote PCs  220  having a host controller PC  216  providing a signal  135  to the communications port  214  of controller  36 . The communications port  214  in turn provides a signal indicating the current flow within a circuit breaker selected and any trip setting value stored in local memory for viewing by a remote user. Remote utilization of controller  36  includes a remote digital input using a display based user interface having a display and a keypad combination that provides a digital menu, such as PCs  214  and  220 , allowing settings to either be scrolled through or chosen with the keypad.  
         [0024]    Panelboard  2  optionally includes a neutral current transformer  224  employed with neutral strap (N). Controller  36  receives a signal from neutral current transformer  224  via line  228  to sense current in neutral strap used in the calculations to indicate a ground fault through the main circuit breaker  42 .  
         [0025]    Branch circuit breakers  26  and  30  are disposed below controller  36  as shown in FIG. 3, however they may be disposed in any relation relative to controller  36 . Branch circuit breaker and main circuit breaker are in electrical communication with controller  36  via secondary (control) breaker connections  230 . In one embodiment, secondary breaker connection  230  is an electrical receptacle configured to receive a complementary configured electrical connector disposed on the branch circuit breaker. Three electrical terminals  232 , 234 , 236  depend from the receptacle providing electrical connection to the controller  36 . As discussed above, FIG. 3 shows a hardwired solenoid  100 , the three terminal connections include a common, sensed current, and solenoid trip connections. Two of the terminals  232 , 234  provide a path to and from solenoid  100  to complete an electrical path for actuation of solenoid  100  when commanded by controller  36  via signal  99 . The third terminal  236  is for receiving a signal indicative of the current of the circuit breaker to be processed by controller  36 . It is contemplated that the main circuit breaker  42  is connected to two secondary breaker connections  230  when main circuit breaker  42  has a current transformer  71  and a set of contacts  130  for each of the two power lines L 1 , L 2 . The secondary breaker connections  230  to controller  36  define control bus  70 . In an exemplary embodiment, control bus  70  comprises a set of three wires or conductors for each circuit breaker connected to controller  36 . It is contemplated, however, that control bus  70  is optionally configured with microcontroller  84  to include an addressing means for communication with each circuit breaker installed in panelboard  2 .  
         [0026]    Branch circuit breakers  26  and  30  are electrically connected to power line L 2  via a primary breaker connector  240  that is disposed intermediate a bottom surface of branch circuit breaker  26 , for example, and a top surface of power line conductor L 2 . Primary breaker connector  240  comprises a planar electrically conductive material and is substantially U-shaped having legs  242  disposed on either side of secondary breaker connection  230 . Legs  242  meet at a base portion  244  where two threaded apertures  246  are formed therein to threadably receive a threaded fastener  248  to electrically connect a line strap of one of two branch circuit breakers to be connected to one of power lines L 1 , L 2 . It will be understood that vertically contiguous primary breaker connectors  240  have legs  242  in electrical connection with alternating power lines L 1 , L 2  to equally distribute the current flow in each power line L 1 , L 2  as illustrated by the two primary breaker connectors shown without any branch circuit breaker connected thereto. Alternately, a plug in primary power connection may be employed.  
         [0027]    Reference is generally made to FIGS.  1 - 4  wherein a circuit breaker (main or branch), generally indicated at  300  in FIG. 4, is constructed in accordance with the following discussion herein. It should be understood however, that certain features, such as the circuit trip assembly as disclosed below, is by way of example and not limitation, as it will be clear that an exemplary circuit breaker, most specifically disclosed with reference to FIG. 4, is applicable to a wide range of general circuit breaker constructions, such as the preferred construction disclosed herein (FIG. 4). It should also be understood that the present invention can be adapted to be utilized with prior art circuit breaker constructions, as will be understood by one of skill in the art.  
         [0028]    Circuit breaker  300  includes a housing  312 , a stab line terminal  314  and a stab load terminal  316  which may be fully or at least partially disposed within housing  312 , and a circuit trip assembly  320  which electrically couples line strap  314  and load strap  316  when circuit breaker  300  is in a first (or closed) condition and electrically decouples line strap  314  and load strap  316  when circuit breaker  300  is in a second (or open) condition. Reference to a “second” condition can be initiated by a switch  322  which is connected with a spring  324  to movable contact arm  326 . Circuit breaker  300  is in the first or closed condition in FIG. 4, while the circuit breaker  300  in the second or open condition is not shown. Generally speaking (again the details are omitted for simplicity), a circuit trip assembly  320 , generally indicated at  320 , may include a rotatable cradle generally indicated at  332 , the movable contact arm  326  contactable with line terminal  314 , a magnet  334 , an armature latch  338 , connected at one end to cradle  324  and at another end to an armature  340 , and a braided flexible conductor  342  electrically connecting movable contact arm  324  to load terminal  316 , the functions of which are all well known in the art, along with additional details such as springs and other features for properly biasing the illustrated elements.  
         [0029]    Housing  312  comprises a mechanical compartment  344  and an electronics compartment  346  defined therein. Within the mechanical compartment  344 , line strap  314  is electrically connected to an electrical distribution circuit (not shown). A stationary contact  347  is fixed to the end of the line strap  314 . Rotatably secured within mechanical compartment  344  is movable contact arm  326 . Movable contact arm  326  is electrically connected to flexible conductor  342 , which is electrically connected to load strap  316 . Load strap  316  is electrically connected to a protected portion of the electrical distribution circuit (not shown) via load lug  360  and threaded fastener  362 . Attached to the end of movable contact arm  326  is a movable contact  366 . During quiescent operation of the circuit breaker  300 , the fixed and movable contacts  347  and  366  are in contact with each other, allowing the flow of electrical current from the distribution circuit through the line strap  314 , fixed contact  347 , movable contact  366 , contact arm  326 , flexible connector  342 , load strap  316 , and load lug  360  to the protected portion of the distribution circuit.  
         [0030]    Certain overcurrent conditions (i.e., short circuit) in the electrical distribution circuit will cause the magnet  334  to attract the armature  340  by the electromagnetic force proportional to the current flowing through load terminal  316 . At a predetermined current, the electromagnetic force overcomes a bias acting on the armature  340 , releasing cradle latch  338  in the operating mechanism generally shown at  120  connected to the movable contact arm  326 . When the armature  340  moves toward the stator magnet  334 , the cradle latch trips the operating mechanism  120 , which rotates the contact arm  326  to separate the stationary and movable contacts  347  and  366 . Separation of the stationary and movable contacts  347  and  366  stops the flow of electrical current to the protected portion of the distribution circuit.  
         [0031]    Within the electronics compartment  346  of the circuit breaker housing  312 , a trip mechanism , such as solenoid  100 , is arranged to interact with the release latch of the operating mechanism  120 . Also secured within the electronics compartment  346  is current transformer  71  surrounding load strap  316 . Depending from housing  312  is a module plug  370  for electrically connecting current transformer  71  and solenoid  100  to controller  36 . It should be noted that module plug  370  is configured to make electrical contact with controller  36  before terminal  314  makes electrical contact with either power line L 1 , L 2 . Extending from the module plug  370  are three terminals  372 ,  374  and  376  for electrical connection with terminals  232 ,  234 , and  236  of secondary breaker connection  230  in communication with controller  36 . Terminals  372  and  374  have a wire leading from each lead to solenoid  100  for operation of the solenoid  100  by controller  36 . Terminal  376  has a wire leading to current transformer  71  for receiving a signal indicative of current for the controller  36  to process. Terminals  372 ,  374 ,  376  are optionally connected to the current transformer  71  and solenoid  100  with other methods as known in the art, such as with a printed circuit board and the like.  
         [0032]    In response to the actuation signal  99 , solenoid  100  is activated to pull a plunger  380  to overcome a bias acting on the plunger  380 , releasing cradle latch  338  in operating mechanism  120  connected to movable contact arm  326 . When plunger  380  moves toward solenoid  100 , the cradle latch trips operating mechanism  120 , which rotates the contact arm  326  to separate the stationary and movable contacts  347  and  366 . Separation of stationary and movable contacts  347  and  366  stops the flow of electrical current to the protected portion of the distribution circuit.  
         [0033]    The above described circuit breakers in communication with a single electronic control module (controller  36 ) provides advanced monitoring and control of low ampacity branch circuits connected to a panelboard. Traditionally, such highly accurate protection, control and monitoring has been reserved to industrial applications because of the size and cost associated with this measure of circuit protection. The single controller employed for multiple branch circuit protection and monitoring offers specific tailored control of critical uptime loads connected to these branch circuits, such as computers, servers, routers and the like, while minimizing the space and costs associated with a single controller. Likewise, by maintaining a centralized controller for control of all branch circuit breakers within a panelboard, including the main circuit breaker, existing circuit breaker dimensions may be utilized eliminating the size penalty normally associated with incorporating electronic control of each.  
         [0034]    While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.