Abstract:
Power distribution busses and methods are disclosed that provide flexible protection and alarming capabilities. Various embodiments provide interchangeability of fuses and circuit breakers within the same power distribution bus configuration. These various embodiments also provide discrete alarming for fused lines, discrete alarming for lines with circuit breakers, combined alarming for lines having mixed forms of protection, and/or selectable alarming such as combined versus discrete in relation to employing all fused lines, employing all circuit breaker protected lines, or employing mixed line protection.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of application Ser. No. 11/507,948, filed Aug. 21, 2006, which is a divisional of application Ser. No. 10/914,721, filed Aug. 9, 2004, now U.S. Pat. No. 7,120,002, which is a divisional of application Ser. No. 09/911,360, filed Jul. 23, 2001, now U.S. Pat. No. 6,775,120, which applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to power distribution units and providing power from a bus within the power distribution unit. More particularly, the present invention relates to providing protection and alarming for the bus within the power distribution unit. 
       BACKGROUND 
       [0003]    Power distribution units generally provide current to downstream devices operating at a given voltage. A bus is included in the power distribution unit and acts as a voltage node that provides the current to the devices. The current that is provided to each individual device generally falls within an acceptable range. However, one or more downstream devices may draw more current than normal due to a heavier than normal load or due to a device malfunction. For purposes of protecting both the power distribution unit and the downstream device, it is desirable to block current from the power distribution unit to the downstream device when the current drawn by the device exceeds a threshold amount. 
         [0004]    Limiting the current to the downstream device is often done by including a fuse in each line leading to each device from the bus. The fuse often provides an alarm voltage so that when the fuse blows due to excessive current, the alarm is triggered. However, the conventional use of fuses in power distribution busses has drawbacks when multiple lines of power are being provided by the power distribution unit because the alarm circuit of conventional power distribution units indicates that a fuse is blown but does not indicate which line is blocked due to a blown fuse. Furthermore, conventional power distribution units that are configured to operate with fuses are not configured to operate with circuit breakers on some or all lines. 
         [0005]    Circuit breakers are used by some conventional power distribution units to limit the current in each line. However, conventional power distribution units using circuit breakers suffer from the same drawbacks as those using fuses. A general alarm is generated by the alarm circuit of a conventional power distribution in response to a tripped breaker, but no indication of the particular line that is blocked is provided. Furthermore, conventional power distribution units that are configured to operate with a circuit breaker are not configured to also operate with a fuse on some or all lines. 
         [0006]    It may be useful in some instances to have fuses on some of the lines output by the power distribution bus while having circuit breakers on other lines. Circuit breakers often have an alarming capability that functions by receiving voltage from a voltage source, such as from the alarm circuit itself. Fuses often have an alarming capability that functions by channeling voltage from the power distribution line to the alarm circuitry. Therefore, conventional power distribution units have not permitted interchanging fuses with circuit breakers. 
         [0007]    Thus, there is a need in the art for more flexible protection and alarming capabilities for power distribution buses. 
       SUMMARY 
       [0008]    The embodiments of the present invention address the problems discussed above and others by providing a power distribution bus with flexible protection and alarming features. Various embodiments permit fuses to be mixed with circuit breakers, permit discrete alarming for each line from the bus, permit combined alarming for the lines of the bus, and/or permit selectable discrete or combined alarming. 
         [0009]    The present invention may be viewed as a method of employing fuses and circuit breakers with a power distribution bus. The method involves inserting a fuse with an alarm connector in a first location plugged into the bus for receiving power from the power distribution bus and inserting a circuit breaker with a pair of alarm connectors in a second location plugged into the bus for receiving power from the power distribution unit. The method also involves inhibiting a response from an alarm circuit electrically linked to the first location and second location until the fuse is blown or until the circuit breaker is tripped. 
         [0010]    The present invention may be viewed as a power distribution bus alarm circuit. The power distribution bus includes a first and a second socket, each having three alarm connections and two power connections. The bus also includes an alarm circuit connected to first and second alarm connections of the first and second sockets, with the alarm circuit being responsive to a voltage being applied from the first of the three connections of the first or second socket and being responsive to a voltage being applied across second and third connections of the first or second sockets. The bus additionally includes a voltage source electrically connected to third alarm connections of the first and second sockets. The bus also includes a fuse positioned in the first socket, with the fuse electrically interconnecting the two power connections and isolating the first alarm connection from the power connection when in a non-blown state. Additionally, the bus includes a circuit breaker positioned in the second socket, with the circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the second and third alarm connections when in a tripped state. 
         [0011]    The present invention may be viewed as another method of employing fuses and circuit breakers with a power distribution bus. The method involves inserting a fuse with an alarm connector in a first location in the bus for receiving power from the power distribution unit and inserting a circuit breaker with a pair of alarm connectors in a second location in the bus for receiving power from the power distribution unit. The method additionally involves inhibiting a response from a first alarm circuit electrically linked to the first location until the fuse is blown and inhibiting a response from a second alarm circuit electrically linked to the second location until the circuit breaker is tripped. 
         [0012]    The present invention may be viewed as another power distribution bus alarm circuit. The bus includes a first and a second socket, with each having three alarm connections and two power connections. The bus includes a first alarm circuit connected to first and second alarm connections of the first socket, with the alarm circuit being responsive to a voltage being applied from the first of the three connections of the first socket and being responsive to a voltage being applied across second and third connections of the first socket. The bus also includes a second alarm circuit connected to first and second alarm connections of the second socket, with the alarm circuit being responsive to a voltage being applied from the first of the three connections of the second socket and being responsive to a voltage being applied across second and third connections of the second socket. The bus additionally includes a voltage source electrically connected to third alarm connections of the first and second sockets. Also, the bus includes a fuse positioned in the first socket, with the fuse electrically interconnecting the two power connections and isolating the first alarm connection from the power connection when in a non-blown state. Additionally, the bus includes a circuit breaker positioned in the second socket, with the circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the second and third alarm connections when in a tripped state. 
         [0013]    The present invention may be viewed as another method of employing fuses and circuit breakers with a power distribution bus. The method involves inserting a fuse with an alarm connector in a first location in the bus for receiving power from the power distribution unit and inserting a circuit breaker with a pair of alarm connectors in a second location in the bus for receiving power from the power distribution unit. The method also involves electrically connecting the first location to a first alarm circuit or a second alarm circuit and electrically connecting the second location to the first alarm circuit or to a third alarm circuit. Additionally, the method involves inhibiting a response from the first alarm circuit or second alarm circuit electrically linked to the first location until the fuse is blown and inhibiting a response from the first alarm circuit or third alarm circuit electrically linked to the second location until the circuit breaker is tripped. 
         [0014]    The present invention may be viewed as another power distribution bus alarm circuit. The power distribution bus includes a first and a second socket, with each having three alarm connections and two power connections. The bus also includes a voltage source electrically connected to third alarm connections of the first and second sockets. Additionally, the bus includes a fuse positioned in the first socket, with the fuse electrically interconnecting the two power connections and isolating the first alarm connection from the power connection when in a non-blown state. The bus also includes a circuit breaker positioned in the second socket, with the circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the second and third alarm connections when in a tripped state. The bus additionally includes a first conductive path extending from the first alarm connection of the first socket, with the first conductive path including a first diode that prevents current flow between the first alarm connection of the first socket and the first alarm connection of the second socket. The bus also includes a second conductive path extending from the first alarm connection of the second socket, with the second conductive path including a diode that prevents current flow between the first alarm connection of the second socket and the first alarm connection of the first socket. The bus further includes a third conductive path extending from the second alarm connection of the first socket, with the third conductive path including a diode that prevents current flow between the second alarm connection of the first socket and the second alarm connection of the second socket. The bus also includes a fourth conductive path extending from the second alarm connection of the second socket, with the fourth conductive path including a diode that prevents current flow between the second alarm connection of the second socket and the second alarm connection of the first socket. 
         [0015]    The present invention may also be viewed as a method of employing fuses with a power distribution bus. The method involves inserting a first fuse with an alarm connector in a first location in the bus for receiving power from the power distribution unit and inserting a second fuse with an alarm connector in a second location in the bus for receiving power from the power distribution unit. The method also involves inhibiting a response from a first alarm circuit electrically linked to the first location until the first fuse is blown and inhibiting a response from a second alarm circuit electrically linked to the second location until the second fuse is blown. 
         [0016]    The present invention may be viewed as a power distribution bus alarm circuit. The power distribution bus includes a first and a second socket, each having an alarm connection and two power connections. The bus also includes a first alarm circuit connected to the alarm connection of the first socket, with the first alarm circuit being responsive to a voltage being applied from the alarm connection of the first socket. The bus additionally includes a second alarm circuit connected to the alarm connection of the second socket, with the second alarm circuit being responsive to a voltage being applied from the alarm connection of the second socket. Also, the bus includes a first fuse positioned in the first socket, with the first fuse electrically interconnecting the two power connections and isolating the alarm connection of the first socket from the power connection when in a non-blown state. The bus also includes a second fuse positioned in the second socket, with the second fuse electrically interconnecting the two power connections isolating the alarm connection of the second socket when in a non-blown state. 
         [0017]    The present invention may be viewed as a method of employing circuit breakers with a power distribution bus. The method involves inserting a first circuit breaker with a pair of alarm connectors in a first location in the bus for receiving power from the power distribution unit and inserting a second circuit breaker with a pair of alarm connectors in a second location in the bus for receiving power from the power distribution unit. The method further involves inhibiting a response from a first alarm circuit electrically linked to the first location until the first circuit breaker is tripped and inhibiting a response from a second alarm circuit electrically linked to the second location until the second circuit breaker is tripped. 
         [0018]    The present invention may be viewed as another power distribution bus alarm circuit. The bus includes a first and a second socket, each having two alarm connections and two power connections. The bus also includes a first alarm circuit connected to first and second alarm connections of the first socket, with the alarm circuit being responsive to a voltage being applied across the two connections of the first socket. The bus additionally includes a second alarm circuit connected to first and second alarm connections of the second socket, with the alarm circuit being responsive to a voltage being applied across the two connections of the second socket. The bus also includes a voltage source electrically connected to one of the two connections of the first and second sockets. The bus includes a first circuit breaker positioned in the first socket, with the first circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the two alarm connections when in a non-blown state. The bus also includes a second circuit breaker positioned in the second socket, with the second circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the two alarm connections when in a tripped state. 
         [0019]    The present invention may be viewed as another method of employing fuses with a power distribution bus. The method involves inserting a first fuse with an alarm connector in a first location in the bus for receiving power from the power distribution unit and inserting a second fuse with an alarm connector in a second location in the bus for receiving power from the power distribution unit. The method further involves electrically connecting the first location to a first alarm circuit or a second alarm circuit and electrically connecting the second location to the first alarm circuit or to a third alarm circuit. Additionally, the method involves inhibiting a response from the first alarm circuit or second alarm circuit electrically linked to the first location until the first fuse is blown and inhibiting a response from the first alarm circuit or third alarm circuit electrically linked to the second location until the second fuse is blown. 
         [0020]    The present invention may be viewed as another power distribution bus alarm circuit. The bus includes a first and a second socket, with each having an alarm connection and two power connections. The bus also includes a first fuse positioned in the first socket, with the first fuse electrically interconnecting the two power connections and isolating the alarm connection of the first socket from the power connection when in a non-blown state. The bus includes a second fuse positioned in the second socket, with the second fuse electrically interconnecting the two power connections and isolating the alarm connection of the second socket from the power connection when in a non-blown state. The bus includes a first conductive path extending from the alarm connection of the first socket and a second conductive path extending from the alarm connection of the second socket. The bus also includes a third conductive path extending from the alarm connection of the first socket and a fourth conductive path extending from the alarm connection of the second socket. 
         [0021]    The present invention may be viewed as another method of employing circuit breakers with a power distribution bus. The method involves inserting a first circuit breaker with a pair of alarm connectors in a first location in the bus for receiving power from the power distribution unit and inserting a second circuit breaker with a pair of alarm connectors in a second location in the bus for receiving power from the power distribution unit. The method also involves electrically connecting the first location to a first alarm circuit or a second alarm circuit and electrically connecting the second location to the first alarm circuit or to a third alarm circuit. The method additionally involves inhibiting a response from the first alarm circuit or second alarm circuit electrically linked to the first location until the first circuit breaker is tripped. Also, the method involves inhibiting a response from the first alarm circuit or third alarm circuit electrically linked to the second location until the second circuit breaker is tripped. 
         [0022]    The present invention may be viewed as another power distribution bus alarm circuit. The bus includes a first and a second socket, with each having two alarm connections and two power connections. The bus also includes a voltage source electrically connected to one of the alarm connections of the first and second sockets. The bus includes a first circuit breaker positioned in the first socket, with the first circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the two alarm connections when in a tripped state. The bus also includes a second circuit breaker positioned in the second socket, with the second circuit breaker electrically interconnecting the two power connections when in a non-tripped state and electrically interconnecting the alarm connections when in a tripped state. The bus additionally includes a first conductive path extending from the alarm connection of the first socket not connected to the voltage source and a second conductive path extending from the alarm connection of the second socket not connected to the voltage source. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a schematic of a protection and alarming configuration employing discrete alarming with fuses. 
           [0024]      FIG. 2  is a schematic of a protection and alarming configuration employing discrete alarming with circuit breakers. 
           [0025]      FIG. 3  is a schematic of a protection and alarming configuration employing selectable alarming with fuses. 
           [0026]      FIG. 4  is a schematic of a protection and alarming configuration employing selectable alarming with circuit breakers. 
           [0027]      FIG. 5  is a schematic of a protection and alarming configuration employing combined alarming with mixed fuses and circuit breakers. 
           [0028]      FIG. 6  is a schematic of a protection and alarming configuration employing discrete alarming with mixed fuses and circuit breakers. 
           [0029]      FIG. 7  is a schematic of a protection and alarming configuration employing selectable alarming with mixed fuses and circuit breakers. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]      FIG. 1  shows a protection and alarm configuration  100  for a power distribution bus  146 . This configuration permits fuses to be used for protection while permitting discrete alarming for each distribution line. Several manufacturers make suitable fuses, such as the Cooper Bussman TPCDS-BUL disconnect in conjunction with the Cooper Bussman TPC series fuse. Although two individual distribution lines are shown in each of the drawings, it is to be understood that only two are shown to simplify understanding of the protection and alarm configurations and that any number of distribution lines may be applicable to the various protection and alarming configurations. 
         [0031]    A voltage is provided on the power distribution bus  146  to a terminal  106  of a first socket  102  and to a terminal  110  of a second socket  104 . The first socket has a fuse  101  that passes current from the bus  146  to a second terminal  108  that is connected to the downstream device  148 . Likewise, the second socket has a fuse  103  that passes current from the bus  146  to a second terminal  112  that is connected to the downstream device  150 . The terminals  106 ,  108 ,  110 , and  112  may be of various types such as permanent connections or temporary connections where the alarm configuration circuitry  100  is contained in a plug-in module. The fuses  101 ,  103  protect the power distribution unit and downstream devices  148 ,  150  by breaking the current pathway when the current is excessive to either of the devices  148 ,  150 . 
         [0032]    The first socket  102  may have three alarm connections  114 ,  116 , and  118 , and the second socket  104  may have three alarm connections  120 ,  122 ,  124 . However, in this embodiment only one alarm connection  116 ,  122  of the each socket  102 ,  104  is used. The alarm connection  116  connects to an alarm circuit interface  130  through a conductor  126  forming a conductive path from the first socket  102 . The interface  130  may be any suitable connection, permanent or temporary, that establishes continuity between the socket  102  and an alarm circuit  134 . An alarm circuit  134 , as is known in the art, may generate a remote alarm signal  138 , such as by triggering an internal relay (not shown), and/or may light a light emitting diode (LED)  140  to provide a visual indication as to the condition of the fuse  101 . 
         [0033]    The alarm connection  122  connects to an alarm circuit interface  132  through a conductor  128  forming a conductive path from the second socket  104 . The interface  132  may be of the same type as interface  130 . The interface  132  provides continuity between the second socket  104  and a second alarm circuit  136 . The second alarm circuit  136  may be of the same type as the alarm circuit  134  to generate a remote alarm signal  142  and/or light the LED  144 . 
         [0034]    The fuse  101  of the first socket  102  isolates the distribution bus  146  from the alarm connection  116  when the fuse  101  is not blown, but when the fuse  101  blows the distribution bus  146  is channeled to the alarm connection  116  through the fuse  101 . Likewise, the fuse  103  of the second socket isolates the distribution bus  146  from the alarm connection  122  when the fuse  103  is not blown. The first alarm circuit  134  does not respond to fuse  103  blowing, and the second alarm circuit  136  does not respond to the fuse  101  blowing. Therefore, discrete alarming for each line feeding power to devices  148 ,  150  is provided to permit individual monitoring. 
         [0035]      FIG. 2  shows a protection and alarm configuration  200  for a power distribution bus (not shown). This configuration permits circuit breakers to be used for protection while permitting discrete alarming for each distribution line. Examples of suitable circuit breakers include the Carling CA1-X0-07-819-AXX-C series, the Eaton AM 1R-B2-AC23D-A52, and the Airpax LMLK-1RLS4-31462-10-V. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0036]    The alarm configuration  200  includes a first socket  202  having a terminal  206  that connects to a bus and a terminal  208  that leads to a downstream device. A circuit breaker  201  is inserted into the first socket  202 . The circuit breaker  201  passes current from terminal  206  to terminal  208  until the current becomes excessive. Once the current is excessive, the circuit breaker  201  trips to stop current flow between the terminals  206 ,  208 . The alarm configuration  200  also includes a second socket  204  having a terminal  210  that connects to a bus and a terminal  212  that leads to another downstream device. A circuit breaker  203  is inserted into the second socket  204 . The circuit breaker  203  passes current from terminal  210  to terminal  212  until the current becomes excessive. Once the current is excessive, the circuit breaker  203  trips to stop current flow between the terminals  210 ,  212 . 
         [0037]    As discussed above with reference to  FIG. 1 , the sockets  202 ,  204  may include three alarm connections including connection  214 ,  216 , and  218  for socket  202  and connections  220 ,  222 , and  224  for socket  204 . However, the configuration  200  only uses connections  214  and  218  for socket  202  and connections  220  and  224  for socket  204  to generate an alarm because connections  216  and  222 , although connected to the circuit breakers  201 ,  203  when in a non-tripped state, are not connected to the alarm circuits  234 ,  236 . The alarm connections  218 ,  224  are connected to a voltage source  246  through a conductor  250  and an interface  248 . The voltage source shown provides negative voltage to the alarm circuits but one skilled in the art will recognize that positive voltage could be provided instead. 
         [0038]    Tripping the circuit breaker  201  causes the alarm connection  218  to be connected to the alarm connection  214  and current flows between the voltage source  248  and the alarm circuit  234  through conductor  226  and interface  230 . Likewise, tripping the circuit breaker  203  causes the alarm connection  224  to be connected to the alarm connection  220  and current flows between the voltage source  248  and the alarm circuit  236  through conductor  228  and interface  232 . Thus, when circuit breaker  201  trips, alarm circuit  234  generates a remote alarm signal  238  and/or lights LED  240 . When circuit breaker  203  trips, alarm circuit  236  generates a remote alarm signal  242  and/or lights LED  244 . Circuit breaker  201  has no effect on alarm circuit  236  and circuit breaker  203  has no effect on alarm circuit  234 . Therefore, discrete alarming is provided for each line to permit individual monitoring. 
         [0039]      FIG. 3  shows a protection and alarm configuration  300  for a power distribution bus (not shown). This configuration permits fuses to be used for protection while permitting selection of discrete alarming for each distribution line or a single alarm responsive to several of the distribution lines. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0040]    The alarm configuration  300  includes a first socket  302  with a fuse  301  and a second socket  304  with a fuse  303 . The fuse  301  carries current between terminal  306  and terminal  308 , and fuse  303  carries current between terminal  310  and  312 . Socket  302  may have three alarm connections  314 ,  316 , and  318  and socket  304  may have three alarm connections  320 ,  322 , and  324 . However, only alarm connections  316  and  322  are used. 
         [0041]    If a single alarm responsive to all lines is to be used, then alarm circuit  333  is connected to interface  331 . When fuse  301  blows, current is channeled between the bus terminal  306  and alarm circuit  333  through alarm connection  316 . Alarm connection  316  is connected to the interface  331  through a conductive path  326 . Conductive path  326  may include a diode  346  which is discussed in more detail below with reference to discrete alarming for configuration  300 . The bus voltage at terminal  306  is assumed to be negative for this diode direction. When alarm circuit  333  receives power from socket  302 , a remote alarm signal  335  is generated and/or the LED  337  lights. 
         [0042]    Additionally, if a single alarm responsive to all lines is to be used, then when fuse  303  blows, current is channeled between the bus terminal  310  and alarm circuit  333  through alarm connection  322 . Alarm connection  322  is connected to the interface  331  through a conductive path  328 . Conductive path  328  may include a diode  348  which is also discussed in more detail below with reference to discrete alarming for configuration  300 . As mentioned, negative voltage is assumed at bus terminal  306  for this diode direction. When alarm circuit  333  receives power from socket  302 , the remote alarm signal  335  is generated and/or LED  337  lights as is the case when fuse  301  blows. 
         [0043]    If discrete alarming is desired, then alarm circuit  336  is connected to interface  330  and alarm circuit  334  is connected to interface  332  rather than alarm circuit  333  being connected to interface  331 . If both single and discrete alarming are desired, alarm circuit  333  can be connected to interface  331  as well. If discrete alarming is implemented, then when fuse  301  blows, current flows between bus terminal  306  and alarm circuit  336 . No current flows to alarm circuit  334  due to the fuse  301  being blown because diode  348  prevents current from flowing in that direction through conductive path  328 . Alarm circuit  336  generates a remote alarm signal  342  and/or lights LED  344  in response to fuse  301  blowing. 
         [0044]    Additionally, if discrete alarming is implemented, then when fuse  303  blows, current flows between bus terminal  310  and alarm circuit  334 . No current flows to alarm circuit  336  because diode  346  prevents current from flowing in that direction through conductive path  326 . Alarm circuit  334  generates a remote alarm signal  338  and/or lights LED  340  in response to fuse  303  blowing. 
         [0045]      FIG. 4  shows a protection and alarm configuration  400  for a power distribution bus (not shown). This configuration permits circuit breakers to be used for protection while permitting selection of discrete alarming for each distribution line or a single alarm responsive to several of the distribution lines. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0046]    The configuration  400  has a first socket  402  and second socket  404 . A circuit breaker  401  located in the first socket  402  channels current between the bus terminal  406  and terminal  408  that leads to the downstream device. A circuit breaker  403  located in the second socket  404  channels current between the bus terminal  410  and the terminal  412  that leads to another downstream device. Both sockets may have three alarms connections such as connections  414 ,  416 , and  418  of socket  402  and connections  420 ,  422 , and  424  of socket  404 . However, configuration  400  uses only connections  414 ,  418 ,  420 , and  424  to provide current to the alarm circuits. 
         [0047]    If a single alarm is to be used for several lines, then alarm circuit  433  is connected to interface  430 . When circuit breaker  401  trips, alarm connection  414  is connected to alarm connection  418  and current is established between the voltage source  446  and the alarm circuit  433 . The voltage source  446 , which provides negative voltage as shown in  FIG. 4  or alternatively positive voltage, passes current through conductive path  450  and socket  402  and also through conductive path  425  when providing power to alarm circuit  433 . A diode  449  is included in path  425  and is discussed in more detail below with reference to configuration  400  being implemented with discrete alarming. The alarm circuit  433  generates a remote alarm signal  435  and/or lights LED  437  in response to fuse  401  blowing. 
         [0048]    If the single alarm is in use, then when circuit breaker  403  trips, alarm connection  420  is connected to alarm connection  424  and current is established between the voltage source  446  and the alarm circuit  433 . The voltage source  446  passes current through conductive path  450  and socket  404  and also through conductive path  427  when providing power to alarm circuit  433 . A diode  451  is included in path  427  and is discussed in more detail below with reference to configuration  400  being implemented with discrete alarming. The alarm circuit  433  generates a remote alarm signal  435  and/or lights LED  437  in response to fuse  403  blowing. 
         [0049]    If discrete alarming is to be used for each line, then alarm circuit  434  is connected to interface  431  and alarm circuit  436  is connected to interface  432  instead of alarm circuit  433  being connected to interface  430 . If both discrete alarming and a single alarm are desired, then alarm circuit  433  may also be connected to interface  430 . If discrete alarming is implemented, then when fuse  401  blows, current is established between the voltage source  446  and the alarm circuit  434 . Current is provided by the voltage source  446  through conductive path  450  and conductive path  426 . Diode  451  prevents power from being applied to alarm circuit  436  in response to fuse  401  blowing. Alarm circuit  434  generates a remote alarm signal  438  and/or lights LED  440  in response to fuse  401  blowing. 
         [0050]    If discrete alarming is implemented, then when fuse  403  blows, current is established between the voltage source  446  and the alarm circuit  436 . Current is provided by the voltage source  446  through conductive path  450  and conductive path  428 . Diode  449  prevents power from being applied to alarm circuit  434  in response to fuse  403  blowing. Alarm circuit  436  generates a remote alarm signal  442  and/or lights LED  444  in response to fuse  403  blowing. 
         [0051]      FIG. 5  shows a protection and alarm configuration  500  for a power distribution bus (not shown). This configuration permits fuses and circuit breakers to be mixed for protection while a single alarm is responsive to several of the distribution lines. At any given time, one socket may have a fuse and the other may have a circuit breaker, both may have fuses, or both may have circuit breakers. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0052]    The configuration  500  includes a socket  502  and a socket  504 . Current from the power distribution bus (not shown) is provided through a fuse or circuit breaker in socket  502  from the bus terminal  506  to the terminal  508  that leads to a downstream device. Current from the power distribution bus is also provided through a fuse or circuit breaker in socket  504  from the bus terminal  510  to the terminal  512 . 
         [0053]    When a circuit breaker is used in the first socket  502 , once the circuit breaker trips, current is established between a voltage source  546  and an alarm circuit  534  through connections  514  and  518  of socket  502 . Current passes through interface  540  connected to voltage source  546 , through conductive paths  548  and  526 , and through interface  530 . Conductive path  526  may include a diode  550  that prevents a tripped circuit breaker in socket  504  from providing voltage from supply  546  to the fuse alarm interface  532  through the first socket  502  when the first socket  502  contains a non-tripped circuit breaker. Diode  550  is useful where the bus voltage normally supplied to interface  532  due to a blown fuse is a different voltage than the supply voltage  546 . Alarm circuit  534  generates a remote alarm signal  536  and/or lights LED  538  in response to a tripped circuit breaker in socket  502 . 
         [0054]    When a circuit breaker is used in the second socket  504 , once the circuit breaker trips, current is established between the voltage source  546  and the alarm circuit  534  through connections  520  and  524  of socket  504 . Current passes through interface  540  connected to voltage source  546 , through conductive paths  548  and  527 , and through interface  530 . Conductive path  527  may include a diode  552  that prevents a tripped circuit breaker in socket  502  from providing voltage from supply  546  to the fuse alarm interface  532  through the second socket  504  when the second socket contains a non-tripped circuit breaker. Alarm circuit  534  generates the remote alarm signal  536  and/or lights LED  538  in response to a tripped circuit breaker in the second socket  504 . 
         [0055]    When a fuse is used in the first socket  502 , once the fuse has blown, current is established between the bus and the alarm circuit  534  through connection  516 . Current passes through interface  532  and through conductive path  528 . Conductive path  528  may include a diode  554  that prevents a blown fuse in socket  504  from providing voltage from the bus to the circuit breaker alarm interface  530  through conductive paths  528  and  526  when socket  502  has a non-tripped circuit breaker. Alarm circuit  534  generates a remote alarm signal  536  and/or lights LED  538  in response to a blown fuse in socket  502 . 
         [0056]    When a fuse is used in the second socket  504 , once the fuse has blown, current is established between the bus and the alarm circuit  534  through connection  522 . Current passes through interface  532  and through conductive path  529 . Conductive path  529  may include a diode  556  that prevents a blown fuse in socket  502  from providing voltage from the bus to the circuit breaker alarm interface  530  through conductive paths  529  and  527  when socket  504  has a non-tripped circuit breaker. Alarm circuit  534  generates the remote alarm signal  536  and/or lights LED  538  in response to a blown fuse in socket  504 . 
         [0057]      FIG. 6  shows a protection and alarm configuration  600  for a power distribution bus (not shown). This configuration permits fuses and circuit breakers to be mixed for protection while discrete alarming is provided for each distribution line. At any given time, one socket may have a fuse and the other may have a circuit breaker, both may have fuses, or both may have circuit breakers. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0058]    The configuration  600  includes a socket  602  and a socket  604 . Current from the power distribution bus (not shown) is provided through a fuse or circuit breaker in socket  602  from the bus terminal  606  to the terminal  608  that leads to a downstream device. Current from the power distribution bus is also provided through a fuse or circuit breaker in socket  604  from the bus terminal  610  to the terminal  612 . 
         [0059]    When a fuse is used in the first socket  602 , once the fuse has blown, current is established between the bus and alarm circuit  634 . Current flows through alarm connection  616 , through conductive path  646 , and through interface  631 . Alarm circuit  634  generates a remote alarm signal  638  and/or lights LED  640  in response to a blown fuse in socket  602 . 
         [0060]    When a fuse is used in the second socket  604 , once the fuse has blown, current is established between the bus and alarm circuit  636 . Current flows through alarm connection  622 , through conductive path  648 , and through interface  650 . Alarm circuit  636  generates a remote alarm signal  642  and/or lights LED  644  in response to a blown fuse in socket  604 . 
         [0061]    When a circuit breaker is used in the first socket  602 , once the circuit breaker trips, current is established between the voltage source  666  and the alarm circuit  634 . Voltage source  666  can provide a positive or negative voltage. Current flows through interface  668 , through conductive path  628 , through alarm connections  614  and  618 , through conductive path  626 , and through interface  630 . Alarm circuit  634  generates the remote alarm signal  638  and/or lights LED  640  in response to a tripped circuit breaker in socket  602 . 
         [0062]    When a circuit breaker is used in the second socket  604 , once the circuit breaker trips, current is established between the voltage source  666  and the alarm circuit  636 . Current flows through interface  668 , through conductive path  629 , through alarm connections  624  and  620 , through conductive path  627 , and through interface  632 . Alarm circuit  636  generates the remote alarm signal  642  and/or lights LED  644  in response to a tripped circuit breaker in socket  604 . 
         [0063]      FIG. 7  shows a protection and alarm configuration  700  for a power distribution bus (not shown). This configuration permits fuses and circuit breakers to be mixed for protection while permitting selection of discrete alarming for each distribution line or a single alarm responsive to several of the distribution lines. At any given time, one socket may have a fuse and the other may have a circuit breaker, both may have fuses, or both may have circuit breakers. As previously discussed, two individual distribution lines are shown to simplify understanding of the protection and alarm configurations and any number of distribution lines may be applicable. 
         [0064]    The configuration  700  includes a socket  702  and a socket  704 . Current from the power distribution bus (not shown) is provided through a fuse or circuit breaker in socket  702  from the bus terminal  706  to the terminal  708  that leads to a downstream device. Current from the power distribution bus is also provided through a fuse or circuit breaker in socket  704  from the bus terminal  710  to the terminal  712 . 
         [0065]    When discrete alarms are used for each line and a fuse is placed in socket  702 , once the fuse blows, current is established between the bus and alarm circuit  744 . Current flows through alarm connection  716 , through conductive path  764 , and through interface  770 . The alarm circuit  744  generates a remote alarm signal  748  and/or lights LED  750  in response to a blown fuse in socket  702 . 
         [0066]    When discrete alarms are used for each line and a fuse is placed in socket  704 , once the fuse blows, current is established between the bus and alarm circuit  746 . Current flows through the alarm connection  722 , through conductive path  766 , and through interface  768 . Alarm circuit  746  generates a remote alarm signal  752  and/or lights LED  754  in response to a blown fuse in socket  704 . 
         [0067]    When discrete alarms for each line are used and a circuit breaker is placed in socket  702 , once the circuit breaker trips, current is established between voltage source  788  and alarm circuit  744 . Current flows through interface  790 , through conductive path  791 , through alarm connections  718  and  714 , through conductive path  726 , and through interface  740 . Alarm circuit  744  generates the remote alarm signal  748  and/or lights LED  750  in response to a tripped circuit breaker in socket  702 . 
         [0068]    When discrete alarms for each line are used and a circuit breaker is placed in socket  704 , once the circuit breaker trips, current is established between the voltage source  788  and alarm circuit  746 . Current flows through interface  790 , through conductive path  793 , through alarm connections  724  and  720 , through conductive path  728 , and through interface  742 . Alarm circuit  746  generates the remote alarm signal  752  and/or lights LED  754  in response to a tripped circuit breaker in socket  704 . 
         [0069]    When a single alarm is used for several lines and a fuse is placed in socket  702 , once the fuse blows, current is established between the bus and the alarm circuit  734 . Current flows through alarm connection  716 , through conductive path  760 , and through interface  732 . A diode  784  is placed in conductive path  760  to prevent current from flowing through conductive path  762  to conductive path  726  and alarm circuit  744  when discrete alarming is used and when a non-tripped circuit breaker is in socket  702  and a blown fuse is in socket  704 . Alarm circuit  734  generates a remote alarm signal  736  and/or lights LED  738  in response to a blown fuse in socket  702 . 
         [0070]    When a single alarm is used for several lines and a fuse is placed in socket  704 , once the fuse blows, current is established between the bus and the alarm circuit  734 . Current flows through alarm connection  722 , through conductive path  762 , and through interface  732 . A diode  786  is placed in conductive path  762  to prevent current from flowing through conductive path  760  to conductive path  762  and alarm circuit  746  when discrete alarming is used and when a non-tripped circuit breaker is in socket  704  and a blown fuse in socket  702 . Alarm circuit  734  generates the remote alarm signal  736  and/or lights LED  738  in response to a blown fuse in socket  704 . 
         [0071]    When a single alarm is used for several lines and a circuit breaker is placed in socket  702 , once the circuit breaker trips, current is established between voltage source  788  and alarm circuit  734 . Current flows through interface  790 , through conductive path  791 , through alarm connections  718  and  714 , through conductive path  727 , and through interface  730 . A diode  756  is placed in conductive path  727  to prevent current from flowing between the voltage source  788  and the alarm circuit  744  when discrete alarming is used with a tripped circuit breaker in socket  704  and a non-tripped circuit breaker in socket  702 . Alarm circuit  734  generates the remote alarm signal  736  and/or lights LED  738  in response to a tripped circuit breaker in socket  702 . 
         [0072]    When a single alarm is used for several line and a circuit breaker is placed in socket  704 , once the circuit breaker trips, current is established between voltage source  788  and alarm circuit  734 . Current flows through interface  790 , through conductive path  793 , through alarm connections  724  and  720 , through conductive path  729 , and through interface  730 . A diode  758  is placed in conductive path  729  to prevent current from flowing between the voltage source  788  and the alarm circuit  746  when discrete alarming is used with a tripped circuit breaker in socket  702  and a non-tripped circuit breaker in socket  704 . Alarm circuit  734  generates the remote alarm signal  736  and/or lights LED  738  in response to a tripped circuit breaker in socket  704 . 
         [0073]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made therein without departing from the spirit and scope of the invention.