Abstract:
A circuit breaker includes separable contacts, an operating mechanism opening and closing the contacts, a first processor determining an open or closed state of the contacts, and a wireless transceiver transmitting the open or closed state from the first processor and receiving a signal. A first accessory includes a wireless receiver, a second processor and outputs. A second accessory includes a wireless transmitter, a third processor and a circuit generating the signal for or communicating the signal to the third processor, which outputs the signal to the wireless transmitter, which transmits the signal to the wireless transceiver. The first processor receives the signal from the wireless transceiver and causes the mechanism to open or close the contacts. The wireless receiver receives the open or closed state from the wireless transceiver. The second processor receives the open or closed state from the wireless receiver and outputs the same to the outputs.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention pertains generally to electrical switching apparatus and, more particularly, to such apparatus including a number of accessories. The invention also relates to methods of communicating between a number of accessories and an electrical switching apparatus. 
         [0003]    2. Background Information 
         [0004]    Electrical switching apparatus, such as circuit breakers, are widely used in industrial, commercial and residential applications for protecting electrical conductors and apparatus. Circuit breakers, for example, are used to protect electrical distribution systems from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition. In small circuit breakers, commonly referred to as miniature circuit breakers, used for residential and light commercial applications, such protection is typically provided by a thermal-magnetic trip device. This trip device includes a bimetal, which heats and bends in response to a persistent overcurrent condition. The bimetal, in turn, unlatches a spring powered operating mechanism, which opens the separable contacts of the circuit breaker to interrupt current flow in the protected power system. 
         [0005]    Some circuit breakers include a trip unit, which senses overcurrent conditions in an automatic mode of operation. Upon sensing an overcurrent condition, the trip unit trips the operating mechanism to a trip state, which moves the separable contacts to their open position. It is well known to employ trip units to detect various types of overcurrent trip conditions and to provide various protection functions, such as, for example, a long delay trip, a short delay trip, an instantaneous trip, and/or a ground fault trip. The earliest electronic trip unit circuit designs utilized discrete components such as transistors, resistors and capacitors. More recently, designs, such as disclosed in U.S. Pat. Nos. 4,428,022; and 5,525,985, have included microprocessors, which provide improved performance and flexibility. These digital systems sample the current waveforms periodically to generate a digital representation of the current. The microprocessor uses the samples to execute algorithms, which implement one or more current protection curves. 
         [0006]    Electrical switching apparatus, such as circuit breakers, as well as transfer switches, network protectors and the like, are often equipped with accessories such as, for example and without limitation, auxiliary contacts, bell alarms, open/close pushbuttons, shunt trip devices, and under voltage release (UVR) devices. 
         [0007]    Auxiliary contacts and bell alarms provide signals indicating certain conditions within the apparatus. For example, auxiliary contacts (e.g., without limitation, normally open; normally closed) of an auxiliary switch signal, for example, the open or closed state of separable contacts of the apparatus. Bell alarm contacts signal, for example, the trip state of the apparatus. These mechanical status indicating accessories are often mounted within the apparatus casings and are used by external monitoring and control equipment. 
         [0008]    Open/close pushbuttons provide a remote mechanism to open or close the separable contacts without standing directly in front of the circuit breaker. For example, two normally open switches (one for open and the other for close) can be used for this purpose. If one and only one switch is closed, then the circuit breaker performs the corresponding requested action (open or close the circuit breaker separable contacts). If both switches are either opened or closed, then no action is taken. 
         [0009]    Shunt trip and UVR devices can be employed in a variety of ways to initiate a change in status of the apparatus such as, for example, to trip open the separable contacts of the apparatus in response to an electrical fault condition (e.g., without limitation, current overload; short circuit; under voltage) or other external condition. The connection between the apparatus and the various accessory devices is conventionally accomplished in parallel using two wires per accessory device. The installation of these wires is costly and time consuming. 
         [0010]    U.S. Pat. No. 6,175,780 discloses an electronic trip unit that communicates with plural remote, accessory devices over a two wire communication bus. 
         [0011]    The installation of the above wires is both costly and time consuming. 
         [0012]    There is, therefore, room for improvement in electrical switching apparatus and corresponding accessories. 
         [0013]    There is also room for improvement in methods of communication between electrical switching apparatus and corresponding accessories. 
       SUMMARY OF THE INVENTION 
       [0014]    These needs and others are met by embodiments of the invention, which provide wireless communication between an electrical switching apparatus and a number of accessories thereof. 
         [0015]    In accordance with one aspect of the invention, an electrical switching apparatus comprises: an electrical switching apparatus housing; separable contacts; an operating mechanism structured to open and close the separable contacts; a first processor cooperating with the operating mechanism to determine an open or closed state of the separable contacts; a number of accessories, each of the number of accessories comprising a wireless receiver, a second processor and a number of outputs; and a wireless transmitter structured to wirelessly transmit the open or closed state of the separable contacts from the first processor to the wireless receiver of the number of accessories, wherein the wireless receiver is structured to wirelessly receive the open or closed state of the separable contacts from the wireless transmitter, wherein the second processor is structured to receive the open or closed state of the separable contacts from the wireless receiver and to output the open or closed state of the separable contacts to the number of outputs, and wherein the number of accessories are located on or internal to the electrical switching apparatus housing. 
         [0016]    As another aspect of the invention, an electrical switching apparatus comprises: separable contacts; an operating mechanism structured to open and close the separable contacts; a first processor cooperating with the operating mechanism to open and close the separable contacts; a wireless receiver structured to wirelessly receive a signal; and a number of accessories, each of the number of accessories comprising a wireless transmitter, a second processor and a circuit structured to generate the signal for the second processor or communicate the signal to the second processor, the second processor being structured to output the signal to the wireless transmitter, the wireless transmitter being structured to wirelessly transmit the signal to the wireless receiver, wherein the first processor is structured to receive the signal from the wireless receiver and to responsively cause the operating mechanism to open or close the separable contacts. 
         [0017]    As another aspect of the invention, an electrical switching apparatus comprises: separable contacts; an operating mechanism structured to open and close the separable contacts; a first processor cooperating with the operating mechanism to determine an open or closed state of the separable contacts and to open and close the separable contacts; a wireless transceiver cooperating with the first processor and being structured to wirelessly transmit the open or closed state of the separable contacts from the first processor and to wirelessly receive a signal; a plurality of accessories, a first one of the accessories comprising a wireless receiver, a second processor and a number of outputs, and a second one of the accessories comprising a wireless transmitter, a third processor and a circuit structured to generate the signal for the third processor or communicate the signal to the third processor, the third processor being structured to output the signal to the wireless transmitter, the wireless transmitter being structured to wirelessly transmit the signal to the wireless transceiver, wherein the first processor is structured to receive the signal from the wireless transceiver and to responsively cause the operating mechanism to open or close the separable contacts, wherein the wireless receiver is structured to wirelessly receive the open or closed state of the separable contacts from the wireless transceiver, and wherein the second processor is structured to receive the open or closed state of the separable contacts from the wireless receiver and to output the open or closed state of the separable contacts to the number of outputs. 
         [0018]    As another aspect of the invention, a method of wirelessly communicating between a number of accessory nodes and an electrical switching apparatus including separable contacts, comprises: wirelessly connecting the electrical switching apparatus and the number of accessory nodes to a wireless communication network; wirelessly communicating over the wireless communication network: (a) an open or closed state of the separable contacts from the electrical switching apparatus to one of the number of accessory nodes, and responsively outputting the open or closed state from the one of the number of accessory nodes, or (b) a signal from one of the number of accessory nodes to the electrical switching apparatus, and responsively opening or closing the separable contacts responsive to the signal; employing the electrical switching apparatus including an electrical switching apparatus housing; and locating the number of accessory nodes on or internal to the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
           [0020]      FIG. 1  is a block diagram of a circuit interrupter and a number of wireless accessory nodes in accordance with embodiments of the invention. 
           [0021]      FIG. 2  is a schematic diagram in block form showing a wireless accessory communication network in accordance with embodiments of the invention. 
           [0022]      FIGS. 3-6  are block diagrams of some of the wireless accessory nodes of  FIG. 1 . 
           [0023]      FIGS. 7-9  are block diagrams of circuit breakers in accordance with other embodiments of the invention. 
           [0024]      FIG. 10  is a schematic diagram in block form showing a wireless accessory communication network in accordance with other embodiments of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
         [0026]    As employed herein, the term “processor” means a programmable analog and/or digital device that can store, retrieve, and process data; a computer; a workstation; a personal computer; a microprocessor; a microcontroller; a microcomputer; a central processing unit; a mainframe computer; a mini-computer; a server; a networked processor; or any suitable processing device or apparatus. 
         [0027]    As employed herein, the term “wireless” shall expressly include, but not be limited by, radio frequency (RF), light or visible light or infrared light not using optical fibers, ultrasound, wireless area networks, such as, but not limited to, IEEE 802.11 and all its variants (e.g., without limitation, 802.11a; 802.11b; 802.11g), IEEE 802.15 and all its variants (e.g., without limitation, 802.15.1; 802.15.3, 802.15.4), IEEE 802.16 and all its variants, other wireless communication standards (e.g., without limitation, ZigBee™ Alliance standard), HyperLan, DECT, PWT, pager, PCS, Wi-Fi, Bluetooth™, and cellular. 
         [0028]    As employed herein, the term “wireless communication network” means a communication network employing wireless communications. 
         [0029]    As employed herein, the term “network coordinator” (NC) means a communicating device, which operates as the central controller in an ad-hoc communication network or a wireless communication network. 
         [0030]    As employed herein, the term “network device” (ND) means a communicating device, which participates in a wireless communication network, and which is not a network coordinator. 
         [0031]    As employed herein, the term “node” includes a ND, a NC or other node, which participates in an ad-hoc communication network or a wireless communication network. 
         [0032]    The invention is described in association with a circuit breaker, although the invention is applicable to a wide range of electrical switching apparatus. 
       Example 1 
       [0033]    Referring to  FIG. 1 , an electronic trip unit  10  of a circuit interrupter, such as circuit breaker  11 , protects and captures waveforms in an AC electrical power distribution system  12 , which represents a load. The power distribution system  12  (e.g., without limitation, an electrical system; an AC electric power system; a power circuit) has three phase conductors  14 A, 14 B, 14 C, and a neutral conductor  14 N. Current transformers  16 A, 16 B, 16 C, 16 N sense current flowing in each of these conductors. Current transformer  16 G is a zero sequence transformer, which indirectly measures ground current by directly measuring the sum of the phase and neutral currents. These currents are sensed by conditioning circuits  80  and  82 , which prepare the signals for processing by analog-to-digital (A/D) converters  22  and  84 , respectively. Phase-to-neutral voltages are sensed from the three phase conductors  14 A, 14 B, 14 C by respective potential transformers  18 A, 18 B, 18 C and are inputted to conditioning circuit  82  for processing by the A/D converter  84 . The conditioning circuits  80  and  82  scale the current and voltage signals to a suitable range for conversion by the A/D converters  22  and  84  for input to processors (e.g., without limitation, microcomputers)  24  and  46 , respectively. 
         [0034]    The A/D converter  84  samples analog voltages and currents, for example, at sampling instances determined by interrupts generated by the processor  46  in a manner more particularly described in U.S. Pat. No. 5,600,527, and the patents referenced therein. The processor  46  utilizes the data generated by the digital samples to provide voltage based protection functions, for example, under/over voltage protection for the electrical system  12 , and also uses the samples for waveform capture and harmonic analysis for metering and display purposes. 
         [0035]    In implementing the overcurrent protection functions, the second processor  24  operates in a protection mode to generate a trip signal when any one of the current/time characteristics of a delayed trip protection function is exceeded. This trip signal is passed to a trip mechanism, such as trip circuit  32 , which opens separable contacts  34 A, 34 B, 34 C in the respective three phase conductors  14 A, 14 B, 14 C of the electrical system  12 . The trip circuit  32  is typically a mechanically latched electronically released mechanism. Although typically not provided in the United States, additional separable contacts can be included to also interrupt current in the neutral conductor  14 N. The processors  24  and  46  can also communicate with one another through, for example, a suitable serial peripheral interface (SPI) link  42 . 
         [0036]    The processor  24  provides the overcurrent protection and communicates with the trip circuit  32  to implement an overcurrent instantaneous trip requirement. The processor  46  also monitors the state of the separable contacts  34 A, 34 B, 34 C or the operating mechanism (not shown) of the circuit breaker  11  through a breaker status circuit  26  to indicate the breaker&#39;s open/closed state. The processor  24  communicates through a wireless transceiver  40  (e.g., without limitation, IEEE 802.15.4; ZigBee) to a wireless communication network  48  (e.g., without limitation, IEEE 802.15.4; ZigBee). 
         [0037]    The electronic trip unit  10  advantageously employs wireless communication between (i.e., to and/or from) the trip unit  10  and a number of wireless accessories  47  (e.g., without limitation, accessory nodes) associated with that particular electronic trip unit  10  through the wireless communication network  48  that is also shown in  FIG. 2 . The circuit interrupter  11  and the wireless accessories  47  are, thus, wirelessly connected to the wireless communication network  48 . This permits, for example, the wireless communication of the open or closed state of the separable contacts  34 A, 34 B, 34 C from the circuit interrupter  11  to one of the wireless accessories  47  (e.g., auxiliary contacts; bell alarm) and responsive outputting of that open or closed state from the corresponding wireless accessory, or a signal (e.g., open; close; trip) from one of the wireless accessories  47  (e.g., shunt trip module; UVR; open/close pushbutton) to the circuit interrupter  11 , which responsively opens or closes the separable contacts  34 A, 34 B, 34 C responsive to that signal. 
       Example 2 
       [0038]    Referring to  FIG. 7 , another circuit interrupter, such as circuit breaker  100  is shown. The circuit breaker  100  includes separable contacts  102 , an operating mechanism  104  structured to open and close the separable contacts, a first processor (e.g., without limitation, a microprocessor (μP))  106  cooperating with the operating mechanism  104  to determine an open or closed state  107  of the separable contacts  102 , and a number of accessories  108 . Each of the accessories  108  includes a wireless receiver (RX)  110 , a second processor (e.g., without limitation, a microprocessor (μP))  112  and a number of outputs  114 . The circuit breaker  100  further includes a wireless transmitter (TX)  115  structured to wirelessly transmit the open or closed state of the separable contacts  102  from the first processor  106  to the wireless receiver  110  of the accessories  108 . The wireless receiver  110  is structured to wirelessly receive the open or closed state of the separable contacts  102  from the wireless transmitter  115 . The second processor  112  is structured to receive the open or closed state of the separable contacts  102  from the wireless receiver  110  and to output the same to the outputs  114 . 
       Example 3 
       [0039]    In this example, the circuit breaker  100  includes a circuit breaker housing  116 , and a number of the accessories  108  are located on or internal to (as shown in  FIG. 7 ) the housing  116  as opposed to being remote from a circuit breaker as is shown with the circuit breaker trip unit  10  of  FIG. 2 . 
       Example 4 
       [0040]    Referring to  FIG. 8 , another circuit interrupter, such as circuit breaker  100 ′, is similar to the circuit breaker  100  of  FIG. 7 . The circuit breaker  100 ′ includes the separable contacts  102 , the operating mechanism  104  structured to open and close the separable contacts  102 , the first processor  106  cooperating with the operating mechanism  104  to open and close the separable contacts  102 , a wireless receiver (RX)  118  structured to wirelessly receive a signal  119 , and a number of accessories  120 . Each of the accessories  120  includes a wireless transmitter (TX)  122 , a second processor (e.g., without limitation, a microprocessor (μP))  124  and a circuit  126  structured to generate the signal  119  for the second processor  124  or communicate that signal  119  to the second processor  124 . The second processor  124  is structured to output the signal  119  to the wireless transmitter  122 , which, in turn, is structured to wirelessly transmit the signal  119  through wireless signal  180  to the wireless receiver  118 . The first processor  106  is structured to receive the signal  119  from the wireless receiver  118  and to responsively cause the operating mechanism  104  to open or close the separable contacts  102 . 
       Example 5 
       [0041]    In this example, the circuit breaker  100 ′ includes a circuit breaker housing  116 ′, and a number of the accessories  120  are located on or internal to the housing  116 ′. 
       Example 6 
       [0042]    Referring to  FIG. 9 , another circuit interrupter, such as circuit breaker  100 ″, is similar to the circuit breakers  100  and  100 ′ of  FIGS. 7 and 8 . The circuit breaker  100 ″ includes the separable contacts  102 , the operating mechanism  104  structured to open and close the separable contacts  102 , a first processor (e.g., without limitation, a microprocessor (μP))  123  cooperating with the operating mechanism  104  to determine an open or closed state  107  of the separable contacts  102  and to open and close the separable contacts  102 , a wireless transceiver (RX/TX)  125  cooperating with the first processor  123  and being structured to wirelessly transmit the open or closed state  107  of the separable contacts  102  from the first processor  123 , and to wirelessly receive a signal  127 , and a plurality of accessories  128 . A first accessory  128 A includes the wireless receiver  110 , the second processor  112  and the number of outputs  114 . A second accessory  128 B includes the wireless transmitter  122 , a third processor (e.g., without limitation, a microprocessor (μP))  124 ′ (the second processor  124  of  FIG. 8 ) and a circuit  126 ′ (the circuit  126  of  FIG. 8 ) structured to generate the signal  127  for the third processor  124 ′ or communicate the signal  127  to the third processor  124 ′. The third processor  124 ′ is structured to output the signal  127  to the wireless transmitter  122 , which, in turn, is structured to wirelessly transmit the signal  127  to the wireless transceiver  125 . The first processor  123  is structured to receive the signal  127  from the wireless transceiver  125  and to responsively cause the operating mechanism  104  to open or close the separable contacts  102 . The wireless receiver  110  is structured to wirelessly receive the open or closed state  107  of the separable contacts  102  from the wireless transceiver  125 . The second processor  112  is structured to receive the open or closed state  107  of the separable contacts  102  from the wireless receiver  110  and to output the open or closed state  107  of the separable contacts  102  to the outputs  114 . 
       Example 7 
       [0043]      FIG. 2  shows five examples of the wireless accessories  47  of  FIG. 1 . For example, wireless accessory  150  outputs an auxiliary contact  151 , wireless accessory  152  inputs a shunt trip signal  153 , wireless accessory  154  outputs a bell alarm  155 , wireless accessory  156  generates a UVR trip signal  157 , and wireless accessory  158  generates an open/close signal  159 . 
       Example 8 
       [0044]    Although the wireless communication network  48  of  FIGS. 1 and 2  may be any suitable wireless communication network, such a wireless communication network is preferably selected from the group consisting of an IEEE 802.15.4 wireless communication network and a ZigBee wireless communication network. 
       Example 9 
       [0045]    Although the invention is applicable to one or more wireless accessory nodes (e.g., as shown in  FIGS. 7 and 8 ),  FIG. 9  shows the wireless communication of, for example, both the open or closed state  107  of the separable contacts  102  from the circuit breaker  100 ″ to the first accessory  128 A, which responsively outputs the open or closed state through the output(s)  114 , and the signal  127  (e.g., without limitation, a shunt trip signal to trip open the separable contacts  102 ; a UVR trip signal to trip open such separable contacts; a pushbutton open or close signal to open or close such separable contacts) from the second accessory  128 B to the circuit breaker  100 ″, which opens or closes the separable contacts  102  responsive to that signal. 
       Example 10 
       [0046]    As contrasted with the circuit breakers  100  of FIG.  7  and  100 ′ of  FIG. 8 , as shown with the circuit breaker trip unit  10  of  FIG. 2 , the number of accessory nodes  47  may be located remote from the circuit breaker. 
       Example 11 
       [0047]    Referring to  FIG. 3 , an accessory  160 , which is suitable for use as an auxiliary switch or bell alarm, includes a wireless transceiver (RX/TX)  162 , a processor  164 , and a suitable output interface  166  (e.g., without limitation, a relay including one or both of normally open and normally closed contacts). In this example, when the relay is energized by the processor  164  through a suitable interface, the normally open contact is closed to energize an alarm circuit  168  (shown in phantom line drawing). Hence, the bell alarm accessory  160  is structured to annunciate the tripped open state of a corresponding circuit breaker (e.g., the circuit breaker  100  of  FIG. 7 ). 
       Example 12 
       [0048]    Otherwise, if the accessory  160  is used as an auxiliary switch, the normally open/normally closed contacts preferably track (e.g., without limitation, the normally open contact is closed for the contacts closed state; the normally open contact is open for the contacts open state) the open or closed state of the circuit breaker separable contacts (e.g., the separable contacts  102  of  FIGS. 7-9 ). 
       Example 13 
       [0049]    As shown in  FIG. 4 , a shunt trip accessory  170  includes a wireless transceiver (RX/TX)  172 , a processor  174 , and a suitable input interface  176  (e.g., without limitation, to an external normally open contact  178  (shown in phantom line drawing), which is closed to provide an external trip signal). In this example, a corresponding operating mechanism (e.g.,  104  of  FIG. 8 ) includes a trip mechanism  179  structured to trip open the separable contacts (e.g.,  102  of  FIG. 8 ), and the open or closed state of such separable contacts is a tripped open state. 
       Example 14 
       [0050]    Referring to  FIG. 8 , a wireless signal  180  from the wireless TX  122  to the wireless RX  118  is a trip signal. The accessory  120 , in this example, is a shunt trip accessory, and the circuit  126  is structured to receive the trip signal  119  (e.g., without limitation, from an external contact) and to communicate the trip signal  119  to the processor  124 . In turn, the processor  106  is structured to receive the trip signal from the wireless RX  118  (which may be part of a wireless transceiver (not shown)) and to responsively cause the trip mechanism  179  to trip open the separable contacts  102 . 
         [0051]    Similarly, the shunt trip accessory  152  of  FIG. 2  can be used to provide a remote trip control station. For safety, it is desirable to be able to trip a circuit breaker without standing directly in front of the unit. A normally open switch (not shown) feeds the shunt trip signal  153  for this purpose. In turn, the electronic trip unit  10  reads this switch through the wireless signal  182  of  FIG. 2 , such that if the switch is closed, then the circuit breaker trip unit  10  performs the requested trip action. Such a request may, for example, be confirmed by multiple reads to avoid false action. 
       Example 15 
       [0052]    As shown in  FIG. 5 , a UVR trip accessory  190  includes a wireless transceiver (RX/TX)  192 , a processor  194 , and a suitable input interface  196  (e.g., without limitation, to an alternating current (AC) voltage source  198  (shown in phantom line drawing), which provides the line voltage to a corresponding circuit breaker, such as the circuit breaker  100 ′ of  FIG. 8 ). In this example, the corresponding operating mechanism (e.g.,  104  of  FIG. 8 ) includes the trip mechanism  179  structured to trip open the separable contacts (e.g.,  102  of  FIG. 8 ), and the open or closed state of such separable contacts is the tripped open state. The wireless signal  180  from the wireless TX  122  to the wireless RX  118  is the trip signal. The accessory  120  ( FIG. 8 ), in this example, is a UVR trip accessory, and the circuit  126  is structured to detect an under voltage condition of the AC voltage source  198  ( FIG. 5 ) and responsively generate the trip signal  119  for the processor  124 . The processor  106  is structured to receive the trip signal  119  from the wireless RX  118  (which may be part of a wireless transceiver (not shown)) and to responsively cause the trip mechanism  179  to trip open the separable contacts  102 . 
       Example 16 
       [0053]    As shown in  FIG. 2 , the open/close signal  159  of the open/close pushbutton accessory  158  may be either an open signal or a close signal from one of the two pushbuttons  200 , 202 . Here, the circuit  126  of  FIG. 8  is structured to detect an open request or a close request  119  and responsively generate the open signal or the close signal for the processor  124 . The processor  106  is structured to receive the open signal or the close signal from the wireless receiver  118  (which may be part of a wireless transceiver (not shown)) and to responsively cause the operating mechanism  104  to open or close, respectively, the separable contacts  102 . 
       Example 17 
       [0054]    The electronic trip unit  10  of  FIG. 2  may function as the master and the wireless accessory nodes  47  may function as slaves. The electronic trip unit  10  may serve as the bus “master” node of the wireless communication network  48  that controls remote “slave” nodes such of the wireless communication network, which slave nodes are the various wireless accessory nodes  150 ,  152 ,  154 ,  156  and  158 . The information to and from the remote wireless accessory nodes  47  from and to the master trip unit  10  is carried by wireless messages, such as  157 , 159 , 182 , 204 , 206  rather than by wires or a wired bus. 
       Example 18 
       [0055]    As an alternative to Example 17, a peer-to-peer structure may be employed. In this example, the electronic trip unit  10  and the various wireless accessory nodes  150 ,  152 ,  154 ,  156  and  158  are peer nodes of the wireless communication network  48 . 
       Example 19 
       [0056]    The wireless messages, such as  157 , 159 , 182 , 204 , 206 , preferably convey the information to and from the remote wireless accessory nodes  47  from and to the master trip unit  10  as fast as possible. 
       Example 20 
       [0057]    In Example 17, the master node  10  may employ, for example, one message type (e.g.,  204 ; 206 ) to send a digital output (e.g., an auxiliary switch signal; a bell alarm signal) to one of the slave nodes  47  and another message type (e.g.,  157 ; 159 ; 182 ) to request a digital input (e.g., a shunt trip signal; a UVR trip signal; an open signal; a close signal) from one of the slave nodes  47  for the master/slave approach. 
       Example 21 
       [0058]    In the peer-to-peer approach of Example 18, the various nodes  10 , 47  preferably employ messages that indicate that the sending node has some thing for the receiving node, in order to preferably wirelessly communicate the information between the respective wirelessly communicating nodes in the quickest manner possible. 
       Example 22 
       [0059]      FIG. 6  shows another circuit breaker  100 ′″, which is similar to the circuit breaker  100 ″ of  FIG. 9 . Here, the processor  106  includes the status circuit  26  of  FIG. 1  to determine the open or close state of the separable contacts  102  from the operating mechanism  104 . 
       Example 23 
       [0060]    Referring to  FIG. 10 , one advantage of an example ZigBee™ wireless communication network is its meshing capability in which it is set up as a “peer-to-peer” communication system (as in, for example, Example 18, above). For example, instead of employing a master node, a remote pushbutton wireless node, such as  158 , could actuate a shunt trip wireless node, such as  152 , through signal  159 ′ without the requirement for the circuit breaker electronic trip unit  10  to know about it. Preferably, however, the trip unit  10  knows the source of its input(s). Here, also, additional nodes, such as  208 , 210 , wirelessly communicate (directly and/or indirectly) with the trip unit  10  and/or with one, some or all of the wireless accessories  47 , such as shown with UVR  156 . In addition, some or all of the wireless accessories  47  may communicate with other ones of the wireless accessories  47 , such as shown with the nodes  152 , 158 . 
       Example 24 
       [0061]    In this example, the wireless signal  212  from the node  208  to the UVR  156  is relayed to the trip unit  10  as signal  157 ′ by the UVR  156 . Also, the signal  157 ″ from the trip unit  10  to the UVR  156  is relayed to the node  210  as signal  214  by the UVR  156 . 
       Example 25 
       [0062]    Although separable contacts  34 A, 34 B, 34 C, 102  are disclosed, suitable solid state separable contacts may be employed. For example, the disclosed circuit breakers  100 , 100 ′, 100 ″,  100 ′″ include a suitable circuit interrupter mechanism, such as the separable contacts  102  that are opened and closed by the operating mechanism  104 , although the invention is applicable to a wide range of circuit interruption mechanisms (e.g., without limitation, solid state or FET switches; contactor contacts) and/or solid state based control/protection devices (e.g., without limitation, drives; soft-starters). 
         [0063]    While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.