Patent Publication Number: US-7896665-B2

Title: Stackable electrical panel modules

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 12/197,036, entitled, Stackable Electrical Panel Modules, and filed Aug. 22, 2008. The entire disclosure of the above-identified related application is hereby fully incorporated herein by reference. 
     TECHNICAL FIELD 
     The disclosed apparatus relates generally to electrical panels to connect electrical devices to power sources. Specifically, this application relates to technology that allows users to create an electrical panel from component modules to meet individual requirements. 
     BACKGROUND 
     To protect equipment and personnel when working with single conductor connectors, electrical connectors are attached and removed from electrical panels in a particular order. For example, where a ground connector is used, the ground connector is connected first and disconnected last. Typical electrical panel assemblies include three receptacles (comprising a ground, a neutral, and a live receptacle) or five receptacles (comprising a ground, neutral, and three separate live receptacles). Previous electrical panel assemblies have been limited by the number of receptacles the manufacturer decides to place in an electrical panel assembly. Due to the power requirements of some applications, previous electrical panel assemblies might not fit into one of these preexisting categories. 
     One conventional solution uses an electrical panel assembly with more than the needed number of receptacles where the unused receptacles are sealed or otherwise made non-functional. Another conventional solution requires a manufacturer to make an electrical panel assembly to the user&#39;s unique specifications, which could be both expensive and time consuming. 
     Therefore, a need exists for an electrical panel assembly that fits the individual needs of the user without customization or alteration of an existing electrical panel assembly. 
     SUMMARY 
     The disclosed apparatus relates generally to electrical panel assemblies. More particularly, the disclosed apparatus relates to a modular apparatus having individual modules that may be interconnected to form an electrical panel assembly. The assembly can maintain standards of electrical safety while allowing previously unavailable flexibility. The disclosed apparatus forces electrical connectors to be attached and detached from an electrical panel assembly in a particular order. The electrical panel assembly also may prevent a protective cover over the next receptacle module from being opened before a connector is installed in a preceding module. 
     The electrical panel assembly invention can require the connectors to be attached to and detached from their respective receptacles in a given order. The electrical panel assembly can serve either as an input panel or as an output panel and can be used in electrical systems requiring multiple receptacles. 
     According to one exemplary aspect, an electrical panel assembly comprises a first electrical panel module comprising a first receptacle contained in the module to interface with a first connector. The first receptacle comprises a first rotation ring for the interface between the receptacle and the first connector. The first rotation ring moves between an open position and a closed position. The open position permits connection or disconnection of the first connector from the first receptacle. The closed position prevents connection or disconnection of the first connector from the first receptacle. The first electrical panel module interacts with a second electrical panel module in a manner that, absent connection of the first connector in the first receptacle, the ability of a second electrical panel module receptacle contained in the second electrical panel module can be prevented from connecting to a second connector. 
     According to another exemplary aspect, an electrical panel module is designed to link with a subsequent electrical panel module in series. The electrical panel module comprises a receptacle to interface with a connector. A rotation ring is provided for an interface between the receptacle and the connector. The rotation ring moves between an open position that permits connection or disconnection of the connector from the receptacle and a closed position that prevents connection or disconnection of the connector from the receptacle. A tab interlock interfaces with a subsequent electrical panel module in series. 
     The disclosed apparatus can provide a module that can connect with other modules to form an electrical panel assembly. Each module comprises a receptacle that can accept a connector. Each module comprises various safety mechanisms that prevent improper use once the modules are assembled as an electrical panel assembly. Aspects of the disclosed apparatus include a mechanism that may prevent a receptacle from accepting a connector unless the previous module in series has a connector in its receptacle. This feature may prevent removal of a connector from a module until the subsequent module in sequence has already had a connector removed. This feature enforces the safety requirement that ground connections should be made first and disconnected last. Another aspect includes a lock that may prevent a protective cover from opening to expose the receptacle until the receptacle of the previous module has a connector inserted therein. 
     According to another exemplary aspect, an electrical panel assembly comprises a first electrical panel module comprising a first receptacle to interface with a first connector. A first rotation ring facilitates contact between the first receptacle and the first connector. The first rotation ring rotates in open position which permits connection or disconnection of the first connector from the receptacle. When the rotation ring is in a closed position, the first connector may not be connected or disconnected from the first receptacle. The first electrical panel module interacts with a second electrical panel module in a manner such that the absence of the first connector in the first receptacle prevents the second electrical panel module from accepting a second connector. 
     According to another aspect of an exemplary embodiment, an electrical panel module comprises a module casing that provides a housing for the electrical panel module and is designed to link with a subsequent electrical panel modules in series. The module casing further comprises a receptacle to interface with a connector and a rotation ring for facilitating contact between the receptacle and the connector, where the rotation ring moves between an open position permitting connection or disconnection of the connector from the receptacle and a closed position preventing connection or disconnection of the connector from the receptacle. A tab interlock is operably coupled to interface with the rotation ring and interfaces with a subsequent electrical panel module. Each module casing comprises one or more openings to facilitate internal interconnectivity with a subsequent electrical power module via the tab interlock. 
     These and other aspects, objects, features, and embodiments of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrated embodiments exemplifying the best mode for carrying out the apparatus as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present apparatus may be better understood by reading the following description of non-limitative, exemplary embodiments with reference to the attached drawings, wherein like parts of each of the figures are identified by the same reference character, and which are briefly described as follows. 
         FIG. 1  is a perspective view of a fully assembled electrical panel assembly comprising three electrical panel modules according to an exemplary embodiment. 
         FIG. 2  is a rear perspective view of the electrical panel assembly of  FIG. 1 . 
         FIG. 3A  is an front elevation view of an individual electrical panel module with a cover opened to reveal a receptacle according to an exemplary embodiment. 
         FIG. 3B  is a perspective view of the individual electrical panel module of  FIG. 3A . 
         FIG. 4  is a rear internal view of the electrical panel assembly of  FIG. 1 , illustrating the interconnectivity of one ground electrical panel module and two non-ground electrical panel modules according to an exemplary embodiment. 
         FIG. 5  is a perspective, internal view of the assembly of  FIG. 4 . 
         FIG. 6  is a rear elevation view of an electrical panel module configured for use as a ground electrical panel module according to an exemplary embodiment. 
         FIG. 7  is a rear elevation view of an electrical panel module configured for use as a non-ground electrical panel module according to an exemplary embodiment. 
         FIG. 8  comprises  FIGS. 8A-8C .  FIG. 8A  is a rear perspective of an electrical panel model showing the cover interlock aperture according to an exemplary embodiment. 
         FIG. 8B  is a rear perspective view of an electrical panel module showing a tab interlock aperture according to an exemplary embodiment. 
         FIG. 8C  is a perspective view of a series of elements of an electrical panel model according to an exemplary embodiment. 
         FIG. 9  is a rear perspective view of an electrical panel assembly comprising two non-ground electrical panel modules and having one side panel removed to illustrate how the first electrical panel module is fixed as a modified ground state module while also illustrating how the side panels maintain assembly integrity according to an exemplary embodiment. 
         FIG. 10  is a rear perspective view of two electrical panel modules forming an electrical panel assembly where the first electrical panel module is configured as a ground module and the second electrical panel module is a non-ground module according to an exemplary embodiment. 
         FIG. 11  is a rear perspective view of the electrical panel assembly of  FIG. 10  and having connectors installed into the assembly according to an exemplary embodiment. 
         FIG. 12  is a perspective view of an module comprising a limit switch according to an exemplary embodiment. 
         FIG. 13  is a perspective view of an assembly having individual electrical panel modules integrated with stackable electrical panels to form a stackable electrical panel assembly according to an exemplary embodiment. 
         FIG. 14A  is a perspective view of a housings of the stackable electrical panels illustrated in  FIG. 13  according to an exemplary embodiment. 
         FIG. 14B  is an elevation view of a housing of a stackable electrical panel illustrated in  FIG. 13  according to an exemplary embodiment. 
         FIG. 15  is a perspective view of a stackable electrical panel assembly opened to allow a user to inspect the electrical panel modules according to an exemplary embodiment. 
         FIG. 16  is a perspective view of the stackable electrical panel assembly from  FIG. 15  opened to allow a user to inspect the electrical connection between the electrical panel modules and the power supply according to an exemplary embodiment. 
         FIG. 17  is a perspective view of the stackable electrical panel assembly from  FIG. 15  when closed according to an exemplary embodiment. 
         FIG. 18  is a rear perspective view of an electrical panel assembly comprising three interconnected cam electrical panel modules according to an exemplary embodiment. 
         FIG. 19  is a perspective view of a cam electrical module where both a cover cam interlock and a tab cam interlock are in the first position according to an exemplary embodiment. 
         FIG. 20  is a perspective view of the cam electrical module of  FIG. 19  where both the cover cam interlock and the tab cam interlock are in the second position according to an exemplary embodiment. 
         FIG. 21  is a side perspective view of an external rotation ring lock attached to the spring when in the first position according to an exemplary embodiment. 
         FIG. 22  is an angular perspective view of the tab cam interlock of  FIG. 19  according to an exemplary embodiment. 
         FIG. 23  is an angular perspective view of the cover cam interlock of  FIG. 19  according to an exemplary embodiment. 
         FIG. 24  is an angular perspective view of a spacer according to an exemplary embodiment of  FIG. 19  according to an exemplary embodiment. 
         FIG. 25  is an angular perspective view of the external rotation ring lock of  FIG. 19  according to an exemplary embodiment. 
         FIG. 26  is an angular perspective view of the external rotation ring lock spring according to an exemplary embodiment of  FIG. 19  according to an exemplary embodiment. 
         FIG. 27  is an angular perspective view of the rotation ring of  FIG. 19  according to an exemplary embodiment. 
         FIG. 28  is a side elevation view of the cover lock pin according to an exemplary embodiment. 
         FIG. 29  is an angular perspective view of a modified cover lock pin according to an exemplary embodiment. 
         FIG. 30  is a side perspective view of a cam electrical panel module with a modified cover in a closed position according to an exemplary embodiment. 
         FIG. 31  is a side perspective view of a cam electrical panel module with a modified cover in an open position according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The disclosed apparatus may be better understood by reading the following description of non-limiting embodiments with reference to the attached drawings, wherein like parts in each of the figures are identified by the same reference characters. 
       FIG. 1  is a perspective view of a fully assembled electrical panel assembly  100  comprising three electrical panel modules  102   a - c  according to an exemplary embodiment. Alternative embodiments may have an unlimited number (two or more) of electrical panel modules  102  connected to each other, as will be explained below. 
     Each electrical panel module  102  has multiple moving parts. For illustrative purposes, all elements that shift position have a first position and a second position. The first position occurs when the respective element has not been acted on. The second position occurs when the element has been acted on. In several figures, the associated views are from the rear of the modules. As a result, while numbering typically runs from left to right, the numbering of modules in those figures viewed from the rear perspective will be from right to left to account for the perspective of the figures. 
       FIG. 2  is a perspective view of the rear of the fully assembled, exemplary electrical panel assembly  100  from  FIG. 1 . Structural connections between the electrical panel modules  102   a - c  in the exemplary embodiment are strengthened by use of stackable metallic joining rods  202   a   1 - c   1  and  202   a   2 - c   2  as shown in  FIG. 2 , wherein the stackable metallic joining rods  202   a   2 - c   2  on the underside are obscured in  FIG. 2 . Stackable metallic joining rods  202   a   2 - c   2  are illustrated in  FIG. 4 . These stackable metallic joining rods  202   a   1 - c   1  and  202   a   2 - c   2  interconnect and strengthen the bond between the electrical panel modules  102   a - c  by fixing and aligning the electrical panel modules  102   a - c  to each other. The electrical panel modules  102   a - c  each hold a section of the connector rod  202   a   1 - c   1  and  202   a   2 - c   2 . The connector rod  202   a   1  comprises a female threaded portion that is adjacent to a male threaded portion of connector rod  202   b   1 . The connector rods  202   a   1  and  202   b   1  are coupled together to form a single rod holding the modules  102   a  and  102   b  together. This process is continued with connector rod  202   b   1  and  202   c   1  and also for connector rods  202   a   2 - c   2 . An additional feature that aids in integrating the electrical panel modules  102   a - c  are the tongue and groove seals  204   a - c  that aid in the integrity of the electrical panel modules  102   a - c . Electrical terminals  206   a - c  project from the rear of the modules  102   a - c  to allow the electrical panel modules  102   a - c  to be electrically coupled to a power source (not shown). 
       FIG. 3A  is an front elevation view of an individual electrical panel module  102  with a cover  306  opened to reveal a receptacle  302  according to an exemplary embodiment.  FIG. 3B  is a perspective view of the exemplary electrical panel module  102  illustrated in  FIG. 3A .  FIGS. 3A-3B  illustrate how the cover  306  conceals the receptacle  302 , which comprises an aperture  304  for a connector (not shown) to be installed. The cover  306  in  FIG. 3A  is in an open position allowing access to the receptacle  302 . As will be described below, the connector couples to the receptacle  302 , thereby creating a secure connection. 
     In an exemplary embodiment, the connectors are dimensioned to fit within the apertures  304  of the electrical panel modules  100  and comprise receiving electrical contacts that are sized to interface with transmitting electrical contacts in the electrical panel modules  102   a - c  when installed by rotating the connectors into second position. With a connector installed in a receptacle  302 , the individual elements of the electrical panel module  102  are manipulated, as described hereinafter. Although referred to herein as receiving electrical contacts of the connector and transmitting electrical contacts of the module  102 , the transmitting and receiving functions of those items can be reversed without departing from the scope and spirit of the present invention. 
       FIG. 4  is a rear internal view of the electrical panel assembly  100  of  FIG. 1 , illustrating the interconnectivity of one ground electrical panel module  402   a  and two non-ground electrical panel modules  422   b - c  according to an exemplary embodiment.  FIG. 5  is a perspective view of the assembly  100  from  FIG. 4 . Elements will be referred to from right to left due to the view being from the rear perspective. Referring to  FIGS. 1 and 4 , the rear view of ground module  402   a  corresponds to module  102   a , the rear view of non-ground module  422   b  corresponds to module  102   b , and the rear view of non-ground module  422   c  corresponds to module  102   c . The ground electrical panel module  402   a , and its components referenced in  FIGS. 4-5 , will be described hereinafter with reference to  FIGS. 6 ,  8 , and  9 . The non-ground electrical panel modules  422   b - c , and their components referenced in  FIGS. 4-5 , will be described hereinafter with reference to  FIG. 7-9 . 
       FIG. 6  is a rear elevation view of an electrical panel module  102  configured for use as a ground electrical panel module according to an exemplary embodiment. The ground electrical panel module  402  comprises an aperture  304 . Surrounding the aperture  304  is a rotation ring  412  having a rotation ring tab  410  and being disposed in a rotation channel  416 , where the rotation ring tab  410  interfaces with a tab interlock  414 . A plug rotate lock  408   a  fixes the rotation ring  412  in a first position until an electrical connector (not shown) is installed in the aperture  304 . A plug rotate lock spring  406  biases the plug rotate lock  408  in the first position when a connector is not inserted. The tab interlock  414  stays in the first position (as illustrated) when a connector is not installed due to the bias force of an attached interlock spring  432  until acted upon by the rotation ring tab  410 . 
     As illustrated in  FIGS. 3A and 3B , the ground electrical panel module  402  includes a cover  306  that obstructs entry into the aperture  304  as shown in  FIG. 3   a . In an exemplary embodiment, the ground electrical panel module  402  allows the cover  306  to open without restrictions. Alternatives will be explained below. 
     The insertion of the connector into the aperture  304  acts on the plug rotate lock  408  by applying a lateral force on the plug rotate lock  408  that overcomes the force of the plug rotate lock spring  406 . The insertion of the connector into the aperture  304  moves the plug rotate lock  408  out of the first position to the second position. When the plug rotate lock  408  moves into the second position, the rotation ring  412  surrounding the aperture  304  is free to rotate about the aperture  304 . In an exemplary embodiment, a spring can hold the rotation ring  412  in a first position until the connector placed in the aperture  304  is rotated to force the rotation ring  412  to rotate. The user turns the inserted connector in the freed rotation ring  412  until the rotation ring  412  reaches a second position corresponding to an opposite end of the rotation channel  416 . 
     In an exemplary embodiment, the rotation ring  412  can operate in parallel with a cam lock (not shown) that secures the connector to the receptacle  302  and holds the transmitting electrical contact of the elemental panel module  402  to interact with the receiving electrical contact of the connectors. The receptacle  302  comprises a rivet (not shown) that interacts with the connector by way of a cam cut into the connector. As the connector is inserted into the receptacle  302  and rotated, the rivet interacts with the cam in the connector and couples the connector to the receptacle  302 . This rotation will continue until the connector is fixed in a position allowing electrical coupling. Additionally, the action of the cam locking causes the receiving electrical contacts of the connector to expand inside the receptacle  302 . The coupling of the transmitting and receiving electrical connectors allows power to flow from the electrical panel modules  402  to a device coupled to the connector. In an exemplary embodiment, the cam locks are designed to engage when the rotation ring  412  completes rotating, which is approximately 180 degrees. In an exemplary embodiment, the connectors are designed to have the receiving contacts of the connectors electrically couple with the transmitting contacts of the electrical panel module at or before rotation completes. 
     Before the rotation ring tab  410  encounters the tab interlock  414 , the tab interlock  414  is held in position by the tab interlock spring  432 . The tab interlock  414  reaches the second position when the rotation ring tab  410  moves through the rotation channel  416  and fully engages the tab interlock  414  by the rotation tab  410  entering the tab interlock groove  442  as the rotation ring  412  rotates. A tab interlock opening  428  as shown in  FIG. 8  is provided adjacent to the tab interlock  414  where the tab interlock  414  can link through the tab interlock opening  428  to another electrical panel module  102 , as will be described below. 
       FIG. 7  is a rear elevation view of an electrical panel module  102  configured for use as a non-ground electrical panel module  422  according to an exemplary embodiment.  FIG. 7  includes several additional elements from the ground electrical panel module  402 . The non-ground electrical panel module  422  further comprises a cover interlock  424  held in a first position (as illustrated) by a cover interlock spring  434 . The cover interlock  424  interfaces in a manner to be described below with the tab interlock  414  of the preceding ground electrical panel module  402  in a manner that allows the cover interlock  424  to be manipulated by either the tab interlock  414  of the preceding ground electrical panel module  402 , a tab interlock  414  of a preceding non-ground electrical panel module  422 , or the plug rotate lock  408 . In the first position, the cover interlock  424  prevents the cover  306  for the non-ground electrical panel module  422  from opening by restricting a cover jam  426 , preventing the cover jam  426  from withdrawing from the cover  306 . In the exemplary embodiment, the cover jam  426  is a solid member that projects from the interior of the non-ground electrical panel module  422  into the cover  306  and prevents the cover  306  from rotating about the hinge when the cover interlock  424  acts on the cover jam  426 . In this embodiment, the cover  306  of the receptacle  302  of the non-ground electrical panel module  422  may not be opened until the cover jam  426  is released by a slide  810  coupled to the cover interlock  424 . As long as the cover jam  426  is unable to release, the cover  306  attached to the non-ground electrical panel module  422  may not be opened, thereby preventing connector entry to the receptacle  302  of the module  422 . Adjacent to the cover interlock  424  is a cover interlock opening  430  shown in  FIG. 8 . As shown in  FIG. 8 , a tooth  804  of the cover interlock  424  projects through the cover interlock opening  430  to interface with a tab interlock  414  of a separate electrical panel module  102 . The remaining elements herein operate as they did in the ground electrical panel module  402  and are numbered accordingly. 
       FIGS. 8A-C  and  9  illustrate how various elements aid in interconnectivity between modules.  FIG. 8A  is a rear perspective view of an electrical panel module  102  showing the cover interlock aperture  430  according to an exemplary embodiment. The cover interlock aperture  430  allows the tooth  804  to extend outside the electrical panel module  442 .  FIG. 8B  is a rear perspective view an electrical panel module  102  showing the tab interlock aperture  428  according to an exemplary embodiment. The tab interlock aperture  428  allows a cavity  802  of the tab interlock  414  to interface with a cover interlock  424  of an adjacent module. 
       FIG. 8   c  is a perspective view of a series of elements of an electrical panel module  102  according to an exemplary embodiment. Tab interlocks  414  comprise a cavity  802  on a side opposite to the side having the groove  442 . The cavity  802  corresponds to a tooth  804  on the cover interlock  424 . The tooth  804  and cavity  802  interconnect the cover interlock  424  and tab interlock  414  of their respective modules. When a tab interlock  414  of a module moves to the second position, it forces the cover interlock  424  that it is connected to by means of the tooth  804  and cavity  402  into a second position. The tab interlock  414  further comprises a sleeve  832  that allows the translation from the first position to second position. 
     Cover interlock  424  comprise an indentation, a slide  810 , and a tooth  804 . The tooth  804  allows connectivity with an associated tab interlock  414 . The indentation allows the plug rotate lock  408  to restrict the movements to the tab interlock  414 . The slide allows the door jam  426  to be restricted. The cover interlock  424  further comprises a sleeve  834  that allows the translation from the first position to second position. 
     Another element is the plug rotate lock  408 , which comprises a tab  806  that interconnects to an indentation  808  in the cover interlock  424  when a connector is inserted in an aperture  304 . 
     Another element is the cover jam  426  that prevents the cover  306  over the aperture  304  from opening. Cover jam  426  interacts with the slide  810  in the cover interlock  424 . When the cover interlock  424  is in the first position, the slide  810  restricts the cover jam  426  movement. When the cover interlock  424  is in second position, the cover jam  426  is free to release the cover  306 . 
       FIG. 9  is a rear perspective view of an electrical panel assembly  800  comprising two non-ground electrical panel modules  422   d - e  and having one side panel, or end cap,  902  removed to illustrate how the first electrical panel module  422   d  is fixed as a modified ground state module while also illustrating how the side panels  902  maintain assembly integrity according to an exemplary embodiment. This exemplary embodiment utilizes two non-ground electrical panel modules  422   d - e . Once the non-ground electrical panel modules  422   d - e  are linked in series, the leading edge of the non-ground electrical panel module  422   d  and the trailing edge of the non-ground electrical panel module  422   e  are not connected to other modules. In this embodiment, the side panel, or end cap,  902   e  covering the non-ground electrical panel module  422   e  covers the opening that allows the tab interlock  414   e  to move freely. At the same time, the side panel, or end cap,  902   d  covering non-ground electrical panel module  422   d  comprises a ground notch  906  that locks the cover interlock  424   d  in the second position. The ground notch  906  acts on the cover interlock  424   d  to release the cover jam  426   d  and the plug rotate lock  408   d , mimicking the function of a ground electrical panel module  402 . If a ground electrical panel module  402  is used, the side panel  902  could cover the empty cover interlock opening  430  of a module  402  where the absent cover interlock  424   d  would reside to maintain integrity. 
     The side panel  902  in exemplary embodiments also creates the appearance of a single unit from the perspective of the user when the electrical panel modules  422   d - e  are assembled. In exemplary embodiments, the side panel  902  also can have portions that are oriented such that they are level with the front panels of electrical modules. This configuration gives the appearance of a single unit with a flange bordering the entire assembly, such as shown in  FIG. 1 . 
     The electrical panel module interconnectivity between the cover interlock  424  and the tab interlock  414  of different modules allows for the safety feature between connections, which necessitates having the ground connected first and disconnected last. 
     Although these embodiments show a particular set of mechanisms, alternatives to these mechanisms also may be used without departing from the scope and spirit of the exemplary embodiments. The interconnectivity to form an electrical panel assembly  100  may be accomplished by alternative communication means between the modules, including electronic communication between the modules controlling the restrictions described in the exemplary embodiment. 
     The interaction of the exemplary mechanisms will be explained by way of reference to  FIG. 4 . All of the elements described in  FIGS. 6-9  will be referenced, where elements ending with an ‘a’ will refer to ground module  402   a , elements ending with a ‘b’ will refer to non-ground module  422   b , and elements ending with a ‘c’ will refer to non-ground module  422   c.    
     As previously discussed with reference to  FIG. 4 , insertion of a connector though the aperture  304   a  of ground module  402   a  will overcome the force on the plug rotate lock spring  406   a  to release the plug rotate lock  408   a , thereby allowing the rotation ring  412   a  to rotate with rotation of the connector. The rotation ring tab  410   a  will travel through the rotation channel  416   a  where it will engage with the tab interlock groove  442   a  and press the tab interlock  414   a  against the bias force of the tab interlock spring  432  into the second position. With the rotation ring  412   a  in the second position, the cam lock engages and fixes the connector to the receptacle  302   a , as previously described. 
     Based on the design of the modules in the exemplary embodiment, the tab interlock  414   a  of ground module  402   a  interfaces with the cover interlock  424   b  of non-ground module  422   b . The interface is accomplished via the connection of the tooth  804   b  of the cover interlock  424   b  to the cavity  802   a  of the tab interlock  414   a . The connection between the tooth  804   b  and the cavity  802   a  occurs by the tooth  804   b  passing though the cover interlock aperture  430   b  of the non-ground module  422   b  and connecting to the cavity  802   a  visible through the tab interlock aperture  428   a  of the ground module  402   a . With the tab interlock  414   a  of ground module  402   a  in the second position, the cover interlock  424   b  in the non-ground module  422   b  also enters the second position. 
     When the cover interlock  424   b  of non-ground module  422   b  enters the second position, the slide  810   b  is no longer adjacent to the cover jam  426   b , thereby releasing the cover jam  426   b . With the cover jam  426   b  released, the cover  306   b  obstructing the entrance to the receptacle  302   b  can now open, allowing a second connector to be inserted through the aperture  304   b . The rotation ring  412   b  is held in the first position by a spring that cannot be counteracted until the second connector is installed. With the second connector installed, the rotation ring tab  410   b  will travel through the rotation channel  416   b  with rotation of the second connector, where it will engage with the tab interlock grove  442   b  and press the tab interlock  414   b  into the second position. With the rotation ring  412   b  and the tab interlock  414   b  in the second position, the cam lock engages and fixes the second connector to the receptacle  302   b.    
     When the second connector is inserted into the aperture  304   b  of non-ground module  422   b , the plug rotate lock  408   b  will be placed into the second position. The plug rotate lock  408   b  then interacts with a tab interlock  414   b  by connecting with indentation  808   b  in the tab interlock  414   b , which allows the plug rotate lock  408   b  to keep the cover interlock  424   b  from returning to the first position. Until the plug rotate lock  408   b  returns to the first position, cover interlock  424   b  will be unable to return to the first position. The plug rotate lock  408   b  will not return to the first position until the connector has been removed from the aperture  304   b . Due to the previously discussed connection between the tooth  804   b  of the cover interlock  424   b  and the cavity  802   a  of the tab interlock  414   a  of the ground module  402   a , the tab interlock  414   a  in the ground module  402   a  cannot return to the first position, forcing the rotation ring  412   a  to stay in the second position, since the rotation ring tab  410   a  is held in place by the tab interlock groove  442   a  to force the connector to stay connected to the receptacle  302   a  in the ground electrical panel module  402 . Thus, the ground connector in the ground module  402   a  cannot be removed until the second connector is removed from the non-ground module  422   b.    
     The process from the non-ground module  422   b  continues in the non-ground module  422   c  based on the design of the exemplary embodiment. With the attachment of the second connector to the non-ground module  422   b , the tab interlock  414   b  of the non-ground module  422   b  interfaces with the cover interlock  424   c  of the non-ground module  422   c . The interface is accomplished via the connection of the tooth  804   c  of the cover interlock  424   c  to the cavity  802   b  of the tab interlock  414   b . The connection between the tooth  804   c  and the cavity  802   b  occurs by the tooth  804   c  passing though the cover interlock aperture  430   c  of the non-ground module  422   c  and connecting to the cavity  802   b  visible through the tab interlock aperture  428   b  of the non ground module  422   b . With the tab interlock  414   b  of non-ground module  422   b  in the second position, the cover interlock  424   c  in non-ground module  422   c  also enters the second position. 
     When the cover interlock  424   c  of non-ground module  422   c  enters the second position, the slide  810   c  is moved away from the cover jam  426   c , thereby releasing the cover jam  426   c . With the cover jam  426   c  released, the cover  306   c  obstructing the entrance to the aperture  304   c  can now open, allowing a third connector to be inserted through the aperture  304   c . The rotation ring  412   c  is held in the first position by a spring that cannot be counteracted until the third connector is installed. The rotation ring tab  410   c  will travel through the rotation channel  416   c  with rotation of the third connector where it will engage with the tab interlock groove  442   c  and press the tab interlock  414   c  into the second position. 
     When the third connector is inserted into the aperture  304   c  of non-ground module  422   c , the plug rotate lock  408   c  will be placed into the second position. The plug rotate lock  408   c  then interacts with the cover interlock  424   c  by connecting with the indentation  808   c  in the tab interlock  414   c , which allows the plug rotate lock  408   c  to keep the cover interlock  424   c  from returning to the first position. Until the plug rotate lock  408   c  returns to the first position, cover interlock  424   c  will be unable to release. The plug rotate lock  408   c  will not return to the first position until the third connector has been removed from the aperture  304   c . Due to the previously discussed connection between the tooth  804   c  of the cover interlock  424   c  and the cavity  802   b  of the tab interlock  414   b  of the non-ground module  422   b , the tab interlock  414   b  in the non-ground module  422   b  cannot return to the first position, forcing the rotation ring  412   b  to stay in the second position since the rotation ring tab  410   b  is held in place by the tab interlock groove  442   b  to force the connector to stay connected to the receptacle  302   b  in the non-ground electrical panel module  422   b . Thus, the second connector in the non-ground module  422   b  cannot be removed until the third connector is removed from the non-ground module  422   c.    
     To disconnect the connectors from their respective receptacles  302 , the connectors must be decoupled from the receptacles  302  in reverse order. In the exemplary embodiment, the tab interlock  414   c  of non-ground module  422   c  is not fixed in position, allowing the rotation ring  412   c  to return to the first position with rotation of the third connector to remove the third connector. When the third connector is removed from non-ground module  422   c , the force acting on the plug rotate lock  408   c  is removed and the plug rotate lock  408   c  returns to the first position. With the plug rotate lock  408   c  in the first position, the plug rotate lock  408   c  is disengaged from the cover interlock  424   c  of non-ground module  422   c.    
     With the release of the cover interlock  424   c  of non-ground module  422   c , the tab interlock  414   b  of non-ground module  422   b  now may return to the first position. As a result of the tab interlock  414   b  of non-ground module  422   b  being able to return to the first position, the associated rotation ring  412   b  is now freely rotatable since the tab interlock groove  442   b  can release the rotating ring tab  410   b . The rotation ring  412   b  is now rotated to the first position with rotation of the second connector to remove the second connector from non-ground module  422   b . When the rotation ring  412   b  returns to the first position, the tab interlock spring  432   b  acting on the tab interlock  414   b  of non-ground module  422   b  and the cover interlock spring  434   c  acting on the cover interlock  424   c  of non-ground module  422   c  force both components back to the first position. With the cover interlock  424   c  of non-ground module  422   c  in the first position, the cover jam  426   c  of non-ground module  422   c  is engaged by the slide  810   c , preventing the cover  306   c  of non-ground module  422   c  from opening and preventing a connector from being installed in the aperture  304   c.    
     When the second connector is removed from non-ground module  422   b , the force acting on the plug rotate lock  408   b  is removed and the plug rotate lock  408   b  returns to the first position. With the plug rotate lock  408   b  in the first position, the plug rotate lock  408   b  is disengaged from the cover interlock  424   b  of non-ground module  422   b.    
     With the release of the cover interlock  424   b  of non-ground module  422   b , the tab interlock  414   a  of ground module  402   a  now may return to the first position. As a result of the tab interlock  414   a  of ground module  402   a  being able to return to the first position, the associated rotation ring  412   a  is now freely rotatable since the tab interlock groove  442   a  can release the rotating ring tab  410   a . The rotation ring  412   a  is now rotated to the first position with rotation of the first connector to remove the first connector from ground module  402   a . When the rotation ring  412   b  returns to the first position, the tab interlock spring  432   a  acting on the tab interlock  414   c  of ground module  402   a  and the cover interlock spring  434   b  acting on the cover interlock  424   b  of non-ground module  422   b  force both components back to the first position. With the cover interlock  424   b  of non-ground module  422   b  in the first position, the cover jam  426   b  of non-ground module  422   b  is engaged by the slide  810   b , thereby preventing the cover  306   b  of non-ground module  422   b  from opening and preventing a connector to be installed in the aperture  304   b.    
     When the first connector is removed from ground module  402   a , the force on the plug rotate lock  408   a  is removed. Since this is a ground module  402   a , there is no other module on which to act. The cover  306   a  may still be opened for a new ground connector to be installed. 
     According to an exemplary embodiment, the ground module  402   a  and the non-ground modules  422   b - c  may include an additional safety feature that restricts the decoupling of connectors from their respective modules  402 ,  422 . The cover jam  426  may be designed such that the cover jam  426  may not allow the cover interlock  424  to return to first position until the cover  306  is closed. As a result, a ground module  402  or a non-ground module  422  would not be able to release the associated connector unless the cover  306  of the subsequent module  422  is closed according to an exemplary embodiment. Such an exemplary embodiment is described hereinafter with reference to  FIGS. 29-31 . 
     According to an exemplary embodiment, a lock ring  104   a  ( FIG. 1 ) may be attached to the cover  306   a . When the cover  306   a  is closed, a locking mechanism may be attached to the lock ring  104   a  to prevent the cover  306   a  from opening. Based on an exemplary embodiment, when cover  306   a  cannot open, then none of the subsequent covers  306   b - c  can open. Additionally, lock rings  104  may be attached to any other cover  306  or module  102 , which prevents the locked cover  306  and any subsequent cover  306  from being opened when externally locked. 
     Alternative embodiments may include an electrical panel assembly  100  wherein the first electrical panel module  102   a  may be a module other than a ground module  402 . For example, a non-ground module  422  may be used as the first electrical panel module  102   a  in an electrical panel assembly  100 , if desired. 
       FIGS. 10 and 11  provide a perspective view of a two electrical panel module assembly  800 .  FIG. 10  is a perspective view of the rear of two electrical panel modules  422   d - e  forming the electrical panel assembly  800 , where the electrical panel module  422   d  is configured as a ground module and the electrical panel module  422   e  is a non-ground module according to an exemplary embodiment. Module  422   d  is set to a ground configuration by use of a side panel  902   d . Module  422   d  is connected to a second non-ground electrical panel module  422   e .  FIG. 10  shows module  422   d  with cover interlock  424   d  in the second position, releasing the cover jam  426   d , but with the plug rotate lock  408   d , rotation ring  412   d , and tab interlock  414   d  in the first position. Non-ground electrical panel module  422   e  shows tab interlock  414   e  in the first position, with the plug rotate lock  408   e , rotation ring  412   e , and cover interlock  424   e  also in the first position. Module  422   d  is configured to accept a connector, while non-ground electrical panel module  422   e  currently may not accept a connector due to the cover jam  426   e  causing the cover to remain closed. 
       FIG. 11  is a rear perspective view of the electrical panel assembly  800  of  FIG. 10  where the elements in second position as if the connectors have been installed. Module  422   d  and non-ground electrical panel module  422   e  have cover interlocks  424   d - e , the cover jams  426   d - e , and the cover rotate plug locks  408   d - e  all in the second position. The connector for non-ground electrical panel module  422   e  can be removed since nothing is restricting the tab interlock  414   e  in non-ground electrical panel  422   e . However, as long as a connector is inserted in non-ground electrical panel module  422   e , the cover interlock  424   e  of non-ground electrical panel  422   e  will remain fixed, preventing tab interlock  414   d  in module  422   d  from allowing the rotation ring  412   d  to release the connector in module  422   d.    
     The electrical panel modules  102  are constructed from materials suited to use in the electrical industry. In an exemplary embodiment, materials will be used to make the electrical panel modules  102  lighter and more water resistant. The front panel may be made of stainless steel. Lip seals (not shown) on the covers and gaskets (not shown) protect the internal connections of the receptacles from exposure to water. Rotation rings  412  may also be watertight. O-rings provide seals for various components. Tongue and groove seals  204  provide protection between the side panels and the associated electrical panel modules. The side and rear casings can be constructed from synthetic material. An example would be fiberglass type plastics. Areas that need less strength could utilize micro-blend materials. 
       FIG. 12  is a perspective view of an assembly  1200  comprising a limit switch  1202  according to an exemplary embodiment. A limit switch  1202  is an electrical device that can detect motion with respect to the respective electrical panel modules  102 . In the exemplary embodiment, the limit switch  1202  has an arm  1204  that freely rotates. Such a limit switch  1202  would be used in the assembly where the unit is opened with a hinge  1306 , as shown in  FIG. 13  in a stackable panel assembly  1300  which will be discussed below. This limit switch  1202  can be set to interrupt power to the electrical panel modules  102  in the event the modules  102  are opened by detecting a rotation of, for example, forty five degrees or more about the hinges. One advantage in the use of a limit switch  1202  is that in the event a electrical panel assembly  1300  has to be opened to inspect the electrical panel modules  102 , the limit switch  1202  detects those non-nominal positions to prevent shock to personnel. 
     The electrical panel modules  102  now connected in series can be installed in any location where an electrical panel assembly  100  would be used. This location can include being made a component of a preexisting electrical panel. Other examples include the completed unit being placed in a cavity in a wall or other configuration where the electrical panel modules  102  are visible. 
       FIG. 13  is a perspective view of an assembly  1300  having individual electrical panel modules  102   a - c  integrated with stackable electrical panels  1302   a - c  to form a stackable electrical panel assembly  1300  according to an exemplary embodiment. Each stackable electrical panel  1302  comprises an individual electrical panel module  102  and housing  1304  to hold the electrical panel module  102  independently of any previously existing support structure. These stackable electrical panels  1302  can be connected together to form a stackable panel assembly  1300  comprising the individual electrical panel modules  102 . The stackable panel assembly  1300  comprises all the connections necessary to connect the individual electrical panel modules  102  and housings  1304  to their respective cables as shown in  FIG. 13 . 
       FIG. 14A  is a perspective view of a housing  1304  of the stackable electrical panels illustrated in  FIG. 13  according to an exemplary embodiment.  FIG. 14B  is a rear elevation view of the housing  1304  of the stackable electrical panel illustrated in  FIG. 13  according to an exemplary embodiment. In the exemplary embodiment, the individual electrical modules  102  are mounted on housing  1304  illustrated in  FIG. 14A  that may be opened to reveal the back portion of the electrical panel modules  102  for inspection or repair.  FIG. 15  is front a perspective view of a stackable electrical panel  1300  assembly opened to allow a user to inspect the electrical panel modules  102  according to an exemplary embodiment.  FIG. 16  is a rear perspective view of the stackable electrical panel assembly  1300  from  FIG. 15  opened to allow a user to inspect the electrical connection  1602  between the electrical panel modules  102  and the power supply according to an exemplary embodiment.  FIG. 17  is a perspective view of the stackable electrical panel assembly  1300  from  FIG. 16  when closed according to an exemplary embodiment. 
     Stackable panel assemblies  1300  are assembled in the same manner as the individual electrical panel modules  1302 . Each stackable electrical panel  1302  connects to another stackable electrical panel  1302  in such a manner that the electrical power modules can interconnect as previously described. The stackable electrical panel assemblies also can connect in other suitable methods to maintain the disclosed safety features. 
     Alternatives to the previously disclosed apparatus include the use of different mechanisms to practice the apparatus.  FIG. 18  is a rear perspective view of an electrical panel assembly  1800  comprising three cam electrical panel modules  1822   x - z  according to an alternative exemplary embodiment. 
     Elements will be referred to from right to left due to the view being from the rear perspective. Referring to  FIG. 1 , the rear view of cam electrical panel module  1822   x  corresponds to  102   a , the rear view of cam electrical panel module  1822   y  corresponds to  102   b , and the rear view of cam electrical panel module  1822   z  corresponds to  102   c . A single cam electrical panel module  1822  with elements in first position will be discussed with reference to  FIG. 19 . The single cam electrical panel module  1822  with elements in second position will be discussed with reference to  FIG. 20 . 
       FIG. 19  is an elevation view of a cam electrical module  1822  where both a cover cam interlock  1824  and a tab cam interlock  1814  are in the first position according to an exemplary embodiment. In the exemplary embodiment, the cover cam interlock  1824  in the first position corresponds to the preceding cam electrical panel module  1822  without a connector installed. A tab cam interlock  1814  in the first position corresponds to a configuration without a connector in the receptacle  302  of the module  1822 . 
     The cover  306  for the cam electrical panel module  1822  is controlled by a cover lock pin  1836 . The cover lock pin  1836  in a first position extends toward the cover  306 , preventing the cover  306  from opening. A biasing device (not shown) exerts a force to move the cover lock pin  1836  to a second position, where the cover lock pin  1836  is removed from the cover  306  and allows the cover  306  to open. 
     The cover cam interlock  1824  is freely rotatable around the aperture  304 . Referring to  FIG. 23 , the cover cam interlock  1824  comprises a ring  2306  that operably couples the cover cam interlock  1824  to the module  1822 , and a molded cover cam interlock quarter circular component  1840 . The cover cam interlock quarter circular component  1840  comprises three physical features. The rear of the cover cam interlock quarter circular component  1840  comprises a tapered surface  2302 . As a result of the tapered surface  2302  rotating as part of the cover cam interlock  1824 , the distance between the rear of the cover cam interlock  1824  and a fixed point on the surface of the cam electrical module  1822  changes based on the rotation of the cover cam interlock  1824 . The tapered surface  2302  allows the cover cam interlock  1824  to apply a force to the cover lock pin  1836  depending on the orientation of the cover cam interlock  1824  with respect to the cover lock pin  1836 . 
     Another feature of the cover cam interlock quarter circular component  1840  includes a concave portion  2304  capable of receiving at least a portion of the tab cam interlock  1814 . The concave portion  2304  allows the tab cam interlock  1814  to partially reside behind the cover cam interlock  1824  depending on the position of the rotation ring  1812  and cover cam interlock  1824 . Another feature of the cover cam interlock quarter circular component  1840  is a projection  1842 . The projection  1842  is designed to extend into the area that may be occupied by the tab cam interlock  1814  of a preceding cam electrical panel module in a cam electrical panel assembly  1800 . The projection  1842  may extend outside the cam interlock module  1822  through a cover cam lock aperture  1830  that is substantially similar to the cover lock aperture  430  previously described. The projection  1842  may enter a cam interlock module  1822  though a tab cam interlock aperture  1828  that is substantially similar to the tab interlock aperture  428  previously described. 
     The cover cam interlock  1824  is normally held in the first position by a biasing element. In the exemplary embodiment, the biasing element is a spring  1834 . In an exemplary embodiment, the spring  1834  may be coupled to the cam electrical panel module  1822  by a return spring support, such as a cotter pin. The projection  1842  is designed such that when the tab cam interlock  1814  of a preceding cam electrical panel module  1822  rotates through the area occupied by the projection  1842  when the cover cam interlock  1824  is in the first position, the projection  1842  is acted on and the cover cam interlock  1824  rotates clockwise to the second position in response. Alternatively, the cover cam interlock  1824  may be moved to the second position by a specially constructed side plate with a ground notch designed to place the tab cam interlock  1814  in the second position. 
     With the cover  306  opened, the connector interacts with the rotation ring  1812  when rotated, which facilitates connections between the transmitting contacts of the module and the receiving contacts of the connector. The rotation ring  1812  comprises a receptacle  302  and a rotation ring tab  1810  that extends in a direction opposite from the direction of the receptacle  302  and is located substantially on the outer diameter of the rotation ring  1812 . 
     Referring to  FIG. 27 , on substantially the opposite side of the rotation ring tab  1810  is a cavity  2704  for holding the internal rotation ring lock  2702 . The internal rotation ring lock  2702  is dimensioned to fit in a cavity  2704  of the rotation ring  1812 . This cavity  2704  comprises a mechanism to displace the internal rotation ring lock  2702 . When the connector is not attached to the receptacle  302 , the internal rotation ring lock  2702  is in the first position and extends away from the rotation ring  1812 . When in the first position, the internal plug rotate lock  2702  will be partially disposed within the internal plug rotate lock cavity  2704  and prevents the rotation of the rotation ring  1812 . When the connector is installed, the internal plug rotate lock  2702  enters the second position and is substantially disposed within the internal plug rotate lock cavity  2704 , thereby allowing the rotation ring  1812  to rotate. 
     The cam electrical panel module  1822  further comprises a tab cam interlock  1814 . The tab cam interlock  1814  comprises a ring  1846  and a tab cam interlock quarter circular component  1844  capable of interfacing with the rotation ring  1812 . The rotation of the tab cam interlock  1814  is controlled by the rotation of the rotation ring  1812 . The tab cam interlock quarter circular component  1844  comprises a rotation ring tab aperture  1848 . The rotation ring tab aperture  1848  corresponds to the location or the rotation ring tab  1810 , making the tab cam interlock  1814  move in response to the rotation ring  1812 . Referring to  FIG. 22 , the tab cam interlock quarter circular component  1844  further includes a tooth edge  1850  that comprises teeth  2202  at the outer surface of the tooth edge  1850 . 
       FIG. 20  is a perspective view of the cam electrical module  1822  of  FIG. 19  where both the cover cam interlock  1824  and the tab cam interlock  1814  are in the second position according to an exemplary embodiment. The cam electrical module  1822  is shown as it would be when a connector has been installed, with the cover cam interlock  1824  in the second position and the tab cam interlock  1814  in the second position. Due to the movement of the projection  1842 , an external plug rotation ring lock  1860  is visible. The external plug rotation ring lock  1860  comprises external plug rotate lock teeth  1862  that correspond to the teeth  2202  in the tab cam interlock  1814 . Referring to  FIG. 25 , the external plug rotation ring lock  1860  also comprises a surface  2502  that may be acted on by the internal rotation ring lock  2702 . The external plug rotating ring lock  1860  alternates between a first position and a second position. When the external plug rotation lock  1860  is in first position, it lies in a plane that is different from the plane occupied by the teeth  2202  of a tab cam interlock  1814 . When the rotation ring  1812  acts on the internal rotation ring lock  2702 , the internal rotation ring lock  2702  exerts a force on the external plug rotation ring lock  1860 , moving the external plug rotation ring lock  1860  into the second position that corresponds to the plane occupied by the teeth  2202  of the tab cam interlock  1814 . The external plug rotate lock teeth  1862  from the external plug rotation ring lock  1860  and the tab cam interlock  1814  mesh together when the plug rotation ring lock  1860  is engaged. The interface between the external plug rotate lock  1860  and the tab cam interlock  1814  allows the rotation ring  1812  to be locked in the second position when the external plug rotate lock  1860  is engaged. 
       FIG. 21  is a top view of the external plug rotation ring lock  1860  attached to a hold down spring  1806  when in the first position according to an exemplary embodiment. The external plug rotation ring lock  1860  as shown in  FIG. 21  is held in the first position by a hold down spring  1806 . The biasing force of the hold down spring  1806  pushes the external plug rotation ring lock  1860  towards the cover  306 . When a connector is inserted into the receptacle  302 , the biasing force of the hold down spring  1806  is overcome and the external plug rotation ring lock  1860  is moved into the second position away from the cover  306 . 
       FIGS. 22-28  illustrate various individual elements of the cam electrical panel modules  1822  components discussed in the previous paragraphs.  FIG. 22  is an angular perspective view of the tab cam interlock  1814  of  FIG. 19  according to an exemplary embodiment.  FIG. 23  is an angular perspective view of the cover cam interlock  1824  of  FIG. 19  according to an exemplary embodiment.  FIG. 24  is an angular perspective view of a spacer  2402  of  FIG. 19  according to an exemplary embodiment. The spacer  2402  is used to fill the space between the cover cam interlock  1824  and other sections of the cam electrical panel module  1822 .  FIG. 25  is an angular perspective view of the external plug rotation ring lock  1860 .  FIG. 26  is an angular perspective view of the external rotation ring lock spring  1806  of  FIG. 19  according to an exemplary embodiment.  FIG. 27  is an angular perspective view of the rotation ring  1812  in the exemplary embodiment of  FIG. 19  according to an exemplary embodiment.  FIG. 28  is a side elevation view of the cover lock pin  1836 . In the exemplary embodiment, the first end is designed to interface with the cover  306  and the second end is designed to interface with the tapered surface  2302  of the tab cam interlock  1814 . 
     Based on the previous descriptions of the various elements of the cam electrical panel modules  1822 , the following exemplary embodiment illustrates how the multiple cam electrical panel modules  1822  form a cam electrical panel assembly  1800  as previously shown in  FIG. 18 . Three cam electrical panel modules  1822   x - z  are assembled to form a cam electrical panel assembly  1800 . Side plates  1870   x ,  1870   z  are attached to the leading edge of cam electrical panel module  1822   x  and the trailing edge of cam electrical panel module  1822   z , respectively. The side plate  1870   x  attached to cam electrical panel module  1822   x  comprises a cam ground notch that is substantially similar to the previously described ground notch  906  and mimics a tab cam interlock  1824  of a preceding module in the second position, thereby holding cover cam interlock  1824   x  in the second position and allowing the cover lock pin  1836  to withdraw from the cover  306   x.    
     Cam electrical panel module  1822   x  has the cover cam interlock  1824   x  in the second position. Rotation of the cover cam interlock  1824   x  causes the tapered surface  2302   x  of the cover cam interlock  1824   x  to allow the biasing device acting on the cover lock pin  1836   x  to withdraw the cover lock pin  1836   x  from the cover  306   x . The cover  306   x  may be opened, and a connector may be inserted into the receptacle  302   x , applying a lateral force on the rotation ring  1812   x . The lateral force moves rotation ring  1812   x  in a direction of the internal rotation ring lock  2702   x . The rotation ring  1812   x , internal rotation ring lock  2702   x , and external plug rotation ring lock  1860   x  are adjacent to each other in such a manner that when the rotation ring  1812   x  moves in a lateral direction, the space between the rotation ring  1812   x , internal rotation ring lock  2702   x , and external plug rotation ring lock  1860   x  contact each other. As a result of this relationship, when the connector is completely inserted, the connector forces the internal rotation ring lock  2702   x  to press against the external plug rotation ring lock  1860   x . The result is that external plug rotation ring lock  1860   x  is moved to the second position. Additionally, the internal rotation ring lock  2702   x  is in the second position, which corresponds to becoming substantially housed in the internal plug rotate lock into the cavity  2702   x  of the rotation ring  1812   x.    
     With the internal rotation ring lock  2702   x  in the second position, the rotation ring  1812   x  is now freely rotatable. When rotated, the connector applies a rotational force to move the rotation ring  1812   x  into a second position. The second position is reached when the transmitting contacts of the module are in contact with the receiving contacts of the connector. Alternatively, the contacts be contact each other prior to fully reaching the second position. The tab cam interlock  1814   x  rotates with the rotation ring  1812   x  due to the action of the rotation ring tab  1810   x  through the rotation ring channel  1826   x  that is operably coupled to the tab cam interlock  1814   x  via the rotation ring tab aperture  1848   x . In an exemplary embodiment, the configuration of the tab cam interlock teeth  2202  are designed to correspond with the location where the transmitting and receiving contacts are operably coupled. 
     The installation of the connector in cam electrical panel module  1822   x  affects cam electrical panel module  1822   y . The projection  1842   y  from the cover cam interlock  1824   y  of cam electrical panel module  1822   y  extends into cam electrical panel module  1822   x  via the cover cam interlock aperture  1830   y  of cam electrical panel module  1822   y  and the tab cam interlock aperture  1828   x  of cam electrical panel module  1822   x . When the tab cam interlock  1814   x  of cam electrical panel module  1822   x  reaches the second position, the tab cam interlock  1814   x  of cam electrical panel module  1822   x  displaces the cover cam interlock  1824   y  of cam electrical panel module  1822   y , thereby rotating the cover cam interlock  1824   y  of cam electrical panel module  1822   y  into the second position. 
     With the cover cam interlock  1824   y  of cam electrical panel module  1822   y  in the second position, the tapered surface  2302   y  of the tab cam interlock  1814   y  allows the biasing device acting on the cover lock pin  1836   y  to withdraw the cover lock pin  1836   y  from the cover  306   y . The cover  306   y  may be opened and a connector may be inserted into the receptacle  302   y . The connector applies a lateral force on rotation ring  1812   y . The lateral force moves rotation ring  1812   y  in a direction of internal rotation ring lock  2702   y . The rotation ring  1812   y , internal rotation ring lock  2702   y , and external plug rotation ring lock  1860   y  are adjacent to each other in such a manner that when the rotation ring  1812   y  moves in a lateral direction, the space between the rotation ring  1812   y , internal rotation ring lock  2702   y , and external plug rotation ring lock  1860   y  contact each other. As a result of this relationship, when the connector is completely inserted, the connector forces the internal rotation ring lock  2702   y  to press against the external plug rotation ring lock  1860   y . The result is that external plug rotation ring lock  1860   y  is moved to the second position. Additionally, the internal rotation ring lock  2702   y  is in the second position, which corresponds to becoming substantially housed in 
     With the external plug rotation ring lock  1860   y  in the second position, the external plug rotate lock teeth  1862   y  of the external plug rotation ring lock  1860   y  now interact with the tab cam interlock teeth  2202   x  of the cover cam interlock  1824   x  of cam electrical panel module  1822   x . With the external plug rotate lock teeth  1862   y  of the external plug rotation ring lock  1860   y  unable to rotate, the tab cam interlock  1814   x  of cam electrical panel module  1822   x  is fixed in position, preventing the rotation ring  1812   x  of cam electrical panel module  1822   x  from rotating to release the connector. This feature allows cam electrical panel module  1822   y  to fix the connectors of cam electrical panel module  1822   x  in position, regardless of the actual position of the connector in the cam electrical panel module  1822   x.    
     With the internal rotation ring lock  2702   y  of cam electrical panel module  1822   y  in the second position, the rotation ring  1812   y  is freely rotatable. When rotated, the connector applies a rotational force to move the rotation ring  1812   y  into a second position. The second position is reached when the transmitting contacts of the cam electrical panel module  1822   y  are in contact with the receiving contacts of the connector. Alternatively, the contacts be contact each other prior to fully reaching the second position. The tab cam interlock  1814   y  rotates with the rotation ring  1812   y  due to the action of the rotation ring tab  1810   y  through the rotation ring channel  1826   y  that is operably coupled to the tab cam interlock  1814   y  via the rotation ring tab aperture  1848   y.    
     The installation of the connector in cam electrical panel module  1822   y  affects cam electrical panel module  1822   z . The cover cam interlock projection  1842   z  extends into cam electrical panel module  1822   y  via the tab cam interlock aperture  1828   z  of cam electrical panel module  1822   z  and the cover cam interlock aperture  1830   y  of cam electrical panel module  1822   y . When the tab cam interlock  1814   y  of cam electrical panel module  1822   y  reaches the second position, the tab cam interlock  1814   y  of cam electrical panel module  1822   y  displaces the cover cam interlock  1824   z  of cam electrical panel module  1822   z , rotating the cover cam interlock  1824   z  of cam electrical panel module  1822   z  into the second position. 
     With the cover cam interlock  1824   z  of cam electrical panel module  1822   z  in the second position, the tapered surface  2302   z  of the cover cam interlock  1824   z  allows the biasing device acting on the cover lock pin  1836   z  to withdraw the cover lock pin  1836   z  from the cover  306   z . The cover  306   z  may be opened and a connector may be inserted into the receptacle  302   z . The connector applies a lateral force on rotation ring  1812   z . The lateral force moves the rotation ring  1812   z  in a direction of internal rotation ring lock  2702   z . When completely inserted, the connector forces the internal rotation ring lock  2702   z  to press against external plug rotation ring lock  1860   z . The result is that the internal rotation ring lock  2702   z  is in the second position, which corresponds to becoming substantially housed in the internal plug rotate lock cavity  2704   z  of the rotation ring  1812   z . Additionally, the external plug rotation ring lock  1860   z  is now in a second position. 
     With the external rotation ring lock  1860   z  in the second position, the external plug rotate lock teeth  1862   z  of the external plug rotation ring lock  1860   z  now interact with the tab cam interlock teeth  2202   y  of the tab cam interlock  1814   y  of cam electrical panel module  1822   y . With the external plug rotate lock teeth  1862   z  of the external plug rotation ring lock  1860   z  unable to rotate, the tab cam interlock  1814   y  of cam electrical panel module  1822   y  is fixed in position, preventing the rotation ring  1812   y  of cam electrical panel module  1822   y  from rotating to release the connector. This feature allows the cam electrical panel module  1822   z  to fix the connectors of the cam electrical panel module  1822   y  in position, regardless of the actual position of the connector in cam electrical panel module  1822   y.    
     To disconnect connectors from the modules, the connectors are decoupled from receptacles  302  in reverse order. In the exemplary embodiment, the tab cam interlock  1814   z  of cam electrical panel module  1822   z  is not fixed in position, allowing the rotation ring  1812   z  to freely rotate. The connector is rotated, causing the rotation ring  1812   z  to return to the first position where the connector is removed. When the connector is removed from cam electrical panel module  1822   z , the lateral force acting on the rotation ring  1812   z  is removed, causing the external plug rotation ring lock  1860   z  and internal rotation ring lock  2702   z  to return to the first position. With internal rotation ring lock  2702   z  in the first position, the rotation ring  1812   z  is locked in the first position. With the external plug rotation ring lock  1860   z  in the first position, the external plug rotate lock teeth  1862   z  of external plug rotation ring lock  1860   z  are disengaged from the tab cam interlock  1814   y  of cam electrical panel module  1822   y.    
     With the release of the external rotation ring lock teeth  1862   z  from the tab cam interlock  1814   y  from cam electrical panel module  1822   y , the rotation ring  1812   y  is freely rotatable. The connector is rotated, causing the rotation ring  1812   y  to return to the first position where the connector is removed. Additionally, the return of the rotation ring  1812   y  to the first position causes the tab cam interlock  1814   y  to move to the first position. With the tab cam interlock  1814   y  of cam electrical panel module  1822   y  in the first position, the tab cam interlock  1814   y  no longer acts on the cover cam interlock  1824   z  of cam electrical panel module  1822   z . The cover cam interlock  1824   z  of cam electrical panel module  1822   z  returns to the first position where the tapered surface  2302   z  of the cover cam interlock  1824   z  acts on the cover lock pin  1836   z  to overcome the biasing device. With the biasing force overcome, the cover lock pin  1836   z  enters the cover  306   z , preventing the cover  306   z  from being opened. 
     When the connector is removed from cam electrical panel module  1822   y , the lateral force acting on the rotation ring  1812   y  is removed, causing the external plug rotation ring lock  1860   y  and internal rotation ring lock  2702   y  to return to the first position. With internal rotation ring lock  2702   y  in the first position, the rotation ring  1812   y  is locked in the first position. With the external plug rotation ring lock  1860   y  in the first position, the external plug rotate lock teeth  1862   y  of external plug rotation ring lock  1860   y  are disengaged from the tab cam interlock  1814   x  of cam electrical panel module  1822   x.    
     With the release of the external rotation ring lock teeth  1862   y  from the tab cam interlock  1814   x  from cam electrical panel module  1822   x , the rotation ring  1812   x  is freely rotatable. The connector is rotated, causing the rotation ring  1812   x  to return to the first position where the connector is removed. Additionally, the return of the rotation ring  1812   x  to the first position causes the tab cam interlock  1814   x  to move to the first position. With the tab cam interlock  1814   x  of cam electrical panel module  1822   x  in the first position, the tab cam interlock  1814   x  no longer acts on the cover cam interlock  1824   y  of cam electrical panel module  1822   y . The cover cam interlock  1824   y  of cam electrical panel module  1822   y  returns to the first position where the tapered surface  2302   y  of the cover cam interlock  1824   y  acts on the cover lock pin  1836   y  to overcome the biasing device. With the biasing force overcome, the cover lock pin  1836   y  enters the cover  306   y , preventing the cover  306   y  from being opened. 
     When the connector is removed from cam electrical panel module  1822   x , the lateral force acting on the rotation ring  1812   x  is removed, causing the external plug rotation ring lock  1860   x  and internal rotation ring lock  2702   x  to return to the first position. With internal rotation ring lock  2702   x  in the first position, the rotation ring  1812   x  is locked in the first position. 
     Due to the use of the side plate, the cover cam interlock  1824   x  remains in the second position. As a result, the cover lock pin  1836   x  does not enter the cover  306   x , allowing the cover  306   x  to be opened and a connector to be inserted. 
       FIG. 29  is an angular perspective view of a modified cover lock pin  2900  according to an exemplary embodiment. The modified cover lock pin  2900  accomplishes substantially the same function as the previously-described cover lock pin  1836  except as follows: An alternative embodiment of the cam electrical panel module  1822  uses the modified cover lock pin  2900  to interact with the external plug rotation ring lock  1860  to fix a connector in a previous cam electrical panel module  1822 . The modified cover lock pin  2900  comprises a pin  2902  and a lift plate  2904  coupled to one end of the pin  2902 . A spring  2906  is disposed around the pin  2902 . A plate washer  2908  holds the spring  2906  in position, and the ring member  2910  is disposed in a groove  2902   a  of the pin  2902  to hold the spring  2906  and the plate washer  2908  in position on the pin  2902 . 
       FIG. 30  is a side perspective view of a cam electrical panel module  1822  utilizing the lock pin  2900  and having a modified cover  3002  in a closed position according to an exemplary embodiment. The lock pin  2900  is disposed within a bore  3006  of the module  1822 . In first position, the lock pin  2900  is biased to rest as shown in  FIG. 30 , with the pin  2902  engaged with the modified cover  3002 . When the cover cam interlock  1824  is in first position, the lock pin  2900  is in first position, the concave portion  2304  of the cover cam interlock  1824  prevents movement of the pin  2902  into the module  1822 , and the cover  3002  is closed. Additionally, the lift plate  2904  is disposed adjacent to the external plug rotation ring lock  1860 . 
     The lock pin  2900  is biased to project into the modified cover  3002 . The modified cover  3002  compromises a tapered surface  3004  that is dimensioned to accept the lock pin  2900  while still allowing the modified cover  3002  to open. When the modified cover  3002  is closed, the modified cover lock pin  2900  projects into the modified cover  3002  via the biasing force of the spring  2906 , thereby keeping the modified cover lock pin in first position. 
       FIG. 31  is a side perspective view of a cam electrical panel module  1822  with the modified cover  3002  in an open position according to an exemplary embodiment. As shown in  FIG. 31  the cover cam interlock  1824  has been moved to second position by insertion of a connector (not shown) into a preceding module (not shown). Moving the cover cam interlock  1824  to second position causes the concave portion  2304  of the cover cam interlock  1824  to be disposed adjacent to the pin  2902 , thereby allowing movement of the pin  2902  into the module  1822 . As the cover  3002  is opened, the tapered portion  3004  of the cover  3002  (and then an external, circular portion of the cover) acts on the pin  2902  to push the pin  2902  against the bias force of the spring  2906  and into the module  1822 . Accordingly, the lock pin  2900  is illustrated in second position in  FIG. 31 . As the lock pin  2900  moves to second position, the lift plate  2904  now acts on the external plug rotation ring lock  1860 , moving the external plug rotation ring lock  1860  into second position. As previously discussed, with the external plug rotation ring lock  1860  of a module  1822  in second position, the external plug rotation ring lock teeth  1862  act on the tab cam interlock teeth  2202  of the preceding module, thereby fixing the tab cam interlock  1814  of the preceding module in position. The lift plate  2904  will continue to act on the external plug rotation ring lock  1860  until the modified cover lock pin  2900  returns to first position, which can only occur when the cover  3002  is closed. As a result, a connector cannot be removed from a proceeding module if the subsequent module  1822  in series still has the cover  3002  open. 
     An additional feature involves the use of alternative tongue and seal grooves using a tongue with a tapered lead in a groove with a square bottom. A filling tube similar to an O ring fits between the tongue and groove and conforms to that square when the modules are assembled. 
     Therefore, the present disclosed apparatus is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the presently disclosed apparatus may be modified and practiced in different but equivalent manners apparent to those having ordinary skill in the art and having the benefit of the teachings herein. Having described some exemplary embodiments of the presently disclosed apparatus, it is believed that various modifications are within the purview of those in the art without departing from the scope and spirit of the invention. While numerous changes may be made by those having ordinary skill in the art, such changes are encompassed within the spirit of the disclosed apparatus as defined by the appended claims. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular exemplary embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosed apparatus. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.