Patent Publication Number: US-7591653-B2

Title: Modular power distribution center

Description:
This application claims the benefit of Provisional Application Ser. No. 60/825,020, filed Sep. 8, 2006. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to an electrical power distribution center and more particularly to method and apparatus for distributing electrical power in a vehicle. 
     BACKGROUND OF THE INVENTION 
     The first motorized vehicles had little in the way of an electrical system. All that was required was some way to generate and distribute an ignition potential to each of the cylinders of the small, internal combustion engine that powered these early vehicles. The need to see the road ahead during nighttime operation gave rise to the first electrical accessory: headlights. Interior illumination was added for the operator&#39;s convenience, and a single tail light was considered adequate. Turn signal lights followed, but the simple vehicle radio receiver did not make its appearance until a number of years later. The modern automobile is an impressive collection of electrical hardware: from stereo sound equipment to air conditioning; from power windows, mirrors and seats to keyless entry systems; from vehicle alarms to seat position memory to electrically heated seats. The complexity of vehicle electrical systems has grown almost exponentially since the automobile&#39;s introduction. 
     An automotive electrical system is a formidable combination of high-current and low-current circuitry. In many cases, relays are required for control purposes, and all circuits must be adequately fused to protect expensive components and to guard against the danger of fire. In order to facilitate the replacement of fuses and relays, and to simplify interconnection of electrical hardware, many different electric power distribution systems have been tried. 
     One approach that has been tried with fair consistency is to centralize the mounting of fuses and relays and then route input and output connections from this central location. The first systems built using this approach included a great deal of point-to-point wiring. Hand wiring is very costly, and manual wiring operations are a source of wiring errors that negatively impact product quality. Another approach has been the construction of customized distribution networks stamped from thin metal sheets. These stampings are then shaped so that contact tabs protrude through openings in custom designed plastic shells. Although this approach typically yields a higher quality product, tooling costs can be high for both the plastic shells and the stampings since virtually every automobile model requires a unique distribution system. At least some of this uniqueness aspect is driven by the proliferation of fuse and relay packages. A distribution product must be able to accommodate the fuse and relay components selected by the manufacturer. 
     Another approach centered around the use of flexible circuit board technology, or “flex circuits.” Flex circuits are constructed by depositing conductive material between two flexible insulating layers. Although the unique distribution requirements of each vehicle model would require unique flex circuits for each application, tooling costs are much lower than the metal stamping/custom plastic housing approach described previously. The principal disadvantage of the flex circuit approach is that the conductive layers are very thin, and the high current densities required in vehicle power distribution can lead to overheating and possible eventual failure. 
     In summary, existing modular power distribution centers are hard wired and do not allow for modular integration of electronics. Consequently, a need arises for a vehicle electric power distribution system that can be customized for a particular vehicle with relative ease, that avoids high tooling costs for custom designed components, that is reliable in a high current environment, that will accommodate a wide range of fuse and relay packages, and that is relatively inexpensive to manufacture. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a modular power distribution center that utilizes connectors for interconnectivity, as opposed to hard wiring and allows for the integration of electronics modules onto printed circuit board architecture. Broadly, the power distribution center can include: 
     a modular housing having at least one receptacle for engaging a device and at least one socket for I/O connections; 
     at least one printed circuit board within the modular housing which can comprise at least one I/O connection which corresponds to at least one socket for I/O connections of the modular housing, the printed circuit board being electrically connected to at least one primary buss or the at least one primary buss being integrated into the printed circuit board; and 
     the at least one primary buss having a primary conductive strip, a terminal connected to the primary conductive strip and at least one device interface buss connected to the primary conductive strip, wherein connections to the at least one device interface buss correspond with the at least one receptacle of the modular housing. 
     The modular housing of the power distribution center can include any material that will provide structural integrity for the assembly such as, for example, side walls of plastic, extruded aluminum, etc.; an upper face and a lower face wherein either face can include at least one plate having a grid of receptacle portions defined through the face of the at least one plate, wherein the receptacle portions correspond to connections of the device interface buss; and the other face can include at least one connector module, or is adapted to connect to a remote module, and having at least one socket that corresponds to the I/O connections of the printed circuit board. All connection can be made through either one or both faces. The receptacle portions can be configured to receive in engaging fashion electrical devices including, but not limited to: fuses, relays, resistors, diodes, and switches. The at least one printed circuit board of the modular power distribution center can include a single printed circuit board or two boards. When two printed circuit boards are present, the printed circuit board are electrically coupled to each other, either board can include or provide power distribution from the at least one primary buss, and either can provide electrical connections to the at least one I/O connection. 
     A method for distributing electrical power in a vehicle is disclosed which includes at least one device interface buss having device connections, at least one printed circuit board, and a modular housing which provides a degree of adjustability that is unavailable in prior power distribution centers. The method for distributing electrical power in a vehicle comprises the steps of: 
     providing a power buss having a positive battery terminal and at least one device interface buss having device connections; 
     connecting the power buss to at least one printed circuit board, wherein the at least one printed circuit board has at least one I/O connection; and 
     enclosing the printed circuit board within a housing comprising at least one modular plate having a grid of receptacle portions corresponding to the device connections of the at least one device interface buss and at least one socket corresponding to the at least one I/O connection of the printed circuit board. 
     In one embodiment, the power buss includes a primary buss strip having a length along a first direction selected to provide electrical connections to at least the portion of the housing corresponding to the connections of the electrical devices; connecting the battery positive terminal to the primary buss strip or to the printed circuit board; and connecting at least one device interface buss to a portion of the primary buss strip, wherein the at least one device interface buss has a length along a second direction and is connected to a portion of the primary buss strip to provide connections to the electrical devices. 
     Enclosing the circuit board within the housing may further include providing a modular upper plate and a modular lower plate as a repeatable unit. The number of the modular upper plates corresponds to the electrical device connections to the device interface buss and the device connections to the power distribution center. The number of the modular lower plates corresponds to the I/O connections of the printed circuit board and the I/O connections to the power distribution center. 
     The foregoing has outlined, rather broadly, the features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. While the present invention is embodied in hardware, alternate equivalent embodiments may be employed. Those skilled in the art should realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claim, and the accompanying drawings wherein like reference numerals denote like elements and parts, in which: 
         FIGS. 1 and 3D  are perspective views of one embodiment of a modular power buss (also referred to as primary buss); 
         FIGS. 2A-2C  show perspective views of one embodiment of the assembly of a primary strip to a positive battery terminal in providing one embodiment of a primary bus sub-assembly; 
         FIGS. 3A-3C  show perspective views of the interface buss to the primary strip; 
         FIG. 4A  is a perspective view of an integral rivet; 
         FIG. 4B  is a perspective view of a tool and die tool set for forming an integral rivet between the primary strip and the device interface buss or positive battery terminal; 
         FIGS. 4C-4E  show side cross sectional views of the mechanical connection of the device interface buss and/or positive battery terminal to the primary strip in the power distribution center; 
         FIG. 4F  shows a perspective sectional view of the modular power distribution center with pass through terminals  60  coupled to the printed circuit board. 
         FIG. 4G  is a perspective view of the top of the single printed circuit board of  FIG. 4F ; 
         FIG. 4H  is a perspective view of the bottom of the single printed circuit board of  FIG. 4F ; 
         FIG. 5A  shows a side cross sectional view of the printed circuit boards of the power distribution center; 
         FIG. 5B  shows an upper planar view of the printed circuit board of the power distribution center; 
         FIG. 5C  shows a lower planar view of the printed circuit board of the power distribution center; 
         FIG. 5D  is a perspective view of an assembly of the printed circuit boards and modular bussing; 
         FIG. 5E  is a perspective view of another embodiment of the power distribution center where only one printed circuit board is used and power is routed through the printed circuit board; 
         FIG. 5F  is a perspective view of another embodiment of the power distribution center showing a supplemental printed circuit board coupled to the embodiments of  FIGS. 5A and 5E ; 
         FIG. 5G  is an enlarged perspective view of the supplemental printed circuit board; 
         FIG. 5H  is a expanded perspective view of the power distribution center with a plug in module; 
         FIGS. 6A-6B  are perspective views of a modular upper plate having a grid of receptacle portions corresponding to the electrical device connection of the at least one device interface buss of the modular power distribution center; 
         FIGS. 7A-7D  are perspective views of a modular lower plate having at least one socket corresponding to the I/O connections of the printed circuit board of the modular power distribution center; 
         FIGS. 8A and 8B  are perspective views of the modular upper plate, the modular lower plate, modular power buss and printed circuit boards of the modular power distribution center being assembled; 
         FIG. 9A  is a side cross section view of one embodiment of the housing sidewall of the modular power distribution center; 
         FIG. 9B  is a perspective view of one embodiment of the housing corner connectors of the modular power distribution center; 
         FIG. 9C  is a perspective view of the corner connector for the sidewalls; 
         FIG. 9D  is a perspective view of the outside surface of an end cap for the sidewalls, 
         FIG. 9E  is a perspective view of the inside surface of the end cap of  FIG. 9E ; and 
         FIGS. 10A-10C  are perspective views of one embodiment of an assembled modular distribution center. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention includes a modular power distribution center that provides electrical connections of the device interface buss through mechanical connectors and also provides for integration of the electronic modules onto printed circuit board architectures. 
       FIG. 1  depicts one embodiment of modular power buss  10  (also referred to as primary bus) which may include a positive battery terminal  11  (also referred to as B+ terminal), a primary strip  12 , and at least one device interface buss  13 . The primary buss  10  may be formed of conductive material such as copper. In one embodiment, the components of the primary buss  10  are formed from a sheet material by a stamping operation. 
     Referring to  FIG. 2A , primary strip  12  may be cut to a preselected length along a first direction to provide for attachment of the device interface buss  13 . The length and orientation of the primary bus strip  12  may be selected to contribute to the final electrical device layout to the modular power distribution center.  FIG. 2B  shows one embodiment of a positive battery terminal  11  being connected to a portion of the primary strip  12 . The positive battery terminal  11  is connected to the positive terminal of the power supply and distributes power to the modular power distribution center which is a network of conductive paths having at least first and second In/Out (I/O) connection such as at least one or more printed circuit boards adapted to be coupled to an electrical device having at least two terminals. The connection between the primary strip  12  and the positive battery terminal  11  is by a mechanical connection.  FIG. 2C  shows a primary bus sub-assembly including the positive battery terminal  11  mechanically connected to the primary buss strip  12 . In another embodiment,  FIG. 5D , the power buss is not a separate part of the printed circuit board but is integral with and designed to be incorporated into the conductive routing of the Printed Circuit Board. 
       FIGS. 3A-3B  show embodiments of device interface buss  13 . The device interface buss  13  provides sites for electrical engagement to electrical devices. For the purposes of this disclose the term electrical devices includes, but is not limited to: fuses, relays, resistors, diodes, and switches.  FIG. 3A  depicts one embodiment of a device interface bus  13  configured to provide connections to 280 series devices. In one embodiment, the device interface buss  13  may be configured for engagement to 280 series devices that have a length sufficient to provide for the number of devices which are to be received. The 280 series devices are devices which are manufactured by various companies, one of which is Omron Automotive Electronics, Inc. They have male terminals of a conductive material which are approximately 2.8 mm in width, 0.8 mm thickness and a length which is suitable for making an electrical connection. The standard array, or pattern of the terminals on the devices generally conform to 7.8 mm by 8.1 mm. where the long axis of the terminal is aligned in the 7.8 mm dimension and the short axis in the 8.1 mm dimension. In one embodiment, ten positions for device engagement are provided, it being understood, however, that the number of positions can be increased or decreased to satisfy a predetermined device layout by using variable strip width tooling. The device interface buss  13  is disposed along a direction substantially perpendicular to the direction of the primary buss strip  12 . 
     The device interface buss  13  is configured for mechanical connection to the primary strip  12 .  FIG. 3B  shows a device interface buss  13  having a flag end  14 , where the flag end  14  is overlapped against the primary strip  12  to provide a mechanical connection between the device interface buss  13  and the primary strip  12 . Although, device interface buss  13  having flag end portions  14  is shown, a flagless interface buss can be used and is within the scope of the present invention. Referring to  FIG. 3C , flagless interface buss  13 B may have from two to fifteen or more positions  13 C for electrical device connections. 
       FIG. 3D  shows a primary buss  10  assemblage including battery positive terminal  11 , primary strip  12 , and device interface buss  13 . The number, geometry and length of the interface buss  13 , in combination with the length and geometry of the primary buss strip  12 , provides the layout for electrical device connections to the power distribution center. The primary buss assembly  10  can include four device interface busses  13 C,  13 D,  13 E,  13 F connected to the primary buss strip  12 , where the device interface buss includes, for example, ten (more or less) positions for electrical device connections  13 C, four (more or less) positions for electrical device connections  13 D and one (more or less) position for electrical device connections. It is noted that the primary buss assembly  10  shown in  FIG. 3D  is provided for illustrative purposes only as other configurations have been contemplated and are within the scope of the present invention. 
     The mechanical connection of the device interface buss  13  and the positive battery terminal  11  to the primary strip  12  can be provided by a deformation joint, such as an integral rivet formed between the primary strip  12  and the device interface buss  13  or the positive battery terminal  11 . The connection of the device interface buss  13  and the positive battery terminal  11  to the primary strip  12  can be accomplished by a system know in the art as TOG-L-LOC (a trademark of BTM Corp. of Marysville, Mich.) 
     One example of an integral rivet  15  is shown in  FIG. 4A . The integral rivet  15  is provided by a punch  16  and die tool  17 , as shown in  FIG. 4B . The punch  16  and die  17  work surfaces are preferably configured to form a cup-shaped rivet between the metal surfaces of the primary strip  12  and the device interface buss  13  or the positive battery terminal  11 . A more detailed description of a punch and die tool set that is suitable for providing the integral rivet  15  can be found in U.S. Pat. No. 4,757,608, titled “Apparatus for joining sheet material” and U.S. Pat. No. 4,459,735, titled “Joining sheet metal”. 
     The formation of the integral rivet  15  between the primary strip  12  and the device interface buss  13  or positive battery terminal  11  by a punch and die tool, as shown in  FIG. 4B , is described with reference to  FIGS. 4C-4D . Referring to  FIG. 4C , the primary strip  12  and the device interface buss  13  or positive battery terminal  11  are first positioned in overlapping fashion between the punch  16  and the die  17 . The die  17  is positioning against one outside face of the overlapping metal including a cavity  18  defined by an anvil  19  forming the bottom surface of the cavity  18  (see  FIG. 4B ) and by opposed laterally expansible side wall members  20 . Referring to  FIG. 4B , in a next step the punch  16  draws the metals  11 ,  12 , into the cavity  18  of the die  17 . Referring to  FIG. 4C , the punch  16  then squeezes the bottom of the drawn section laterally extruding the material to be joined into an enlarged shape that mechanically interlock the pieces. The die  17  is configured to provide laterally expandable side wall members  20  that are resiliently biased toward one another and pivot or slide laterally in response to lateral extrusion of the joining material. If desired, other known joining operations can be used such as welding, riveting, terminal type connections, etc. 
     In one embodiment the network of conductive paths comprises two printed circuit boards  23 ,  24  which are electrically connected together (see  FIGS. 5A-5D ). In another embodiment, (see  FIGS. 4F ,  4 G, and  4 H) in place of two printed circuit boards  23 ,  24 , a single printed circuit board  21 A having at least one primary buss integrated into the printed circuit board  21 A is disclosed. With the embodiment of a single printed circuit board  21 A, copper stampings are not required, mechanical fastening of buss bars are not required, pass through terminals can now be used, interconnect pins ( 52  in  FIG. 5A ) are not required, and a reduction of up to forty percent of the terminals needed is obtained.  FIG. 4F  shows a perspective sectional view of the modular power distribution center with pass through terminals  60  coupled to the printed circuit board  21 A.  FIG. 4G  is a perspective view of the top of the printed circuit board assembly  21 B; and  FIG. 4H  is a perspective view of the bottom of the printed circuit board  21 B assembly. 
       FIGS. 5A-5D  show two printed circuit boards  23 ,  24  for use with the modular power distribution center here disclosed. The printed circuit boards  23 ,  24  include conductive circuit paths which distribute power to electrical systems. For the purposes of this disclosure the term electrical systems includes, but is not limited to: head lights, signal lights, vehicle cabin lights, anti-lock brake components, radio&#39;s and stereo systems, power windows, power mirrors, power seats and any other electrical system typically used in motor vehicles. 
     Referring to  FIG. 5A , the printed circuit board  24  includes male blade terminals  50  that provide input and output connections (also referred to as I/O connections) from the modular power distribution center to the electrical systems. The blade terminals can be formed of any conductive material such as, for example, copper or aluminum. The modular power buss is connected to the two printed circuit boards  24 ,  23  and may also be connected to at least one fork terminal  22 . Fork terminals  22  are provided to interface with components which are designed into a circuit in the Power Distribution Center. 
     When two printed circuit boards  23 ,  24  are used, the primary buss distributes power to the upper printed circuit board  23  and electrical connections between the electrical devices and electrical systems, i.e. connections between fuses and I/O connections, are provided by a lower printed circuit board  24 , where the lower printed circuit board  24  and the upper circuit board  23  are connected together electrically. The upper printed circuit board  23  and the lower printed circuit board  24  may be mechanically connected and separated by a spacer  25 .  FIG. 5B  shows an upper planar view of the printed circuit board  23  of the power distribution center;  FIG. 5C  shows a lower planar view of the printed circuit board  24  of the power distribution center; and  FIG. 5D  is a perspective view of an assemblage of the upper and lower printed circuit boards  23 ,  24  and the modular power buss  10 .  FIG. 5E  is a perspective view of the embodiment of the power distribution center where only one printed circuit board  21 A is used and power is routed through the printed circuit board. 
     With either of the two embodiments disclosed, the first being the use of two printed circuit boards  23 ,  24  and the second being the use of a single printed circuit board  21 A, bussing of power can be provided primarily through a series of stamped copper buss bars or power can be routed only through the printed circuit boards. There is no limitation for each embodiment as to how the power is routed. 
     However, the two embodiments have advantages which differ. For example, with the first embodiment, the buss bars and fork terminals are connected with a mechanical joint, such as Tog-L-Loc, using dedicated tooling; and, battery power buss bars are connected to the main buss bars with a resistance weld. With the second embodiment, mechanical fastening of buss bars is not required. 
     During assembly, with the first embodiment, mechanical joints (e.g. Tog-L-Loc), resistance welds, and soldering to the printed circuit board and interconnect pins  52  can be time consuming and difficult. With the second embodiment, the printed circuit board assembly  21 B does not require interconnect pins and associated soldering, or any manufacturing processes associated with buss bars. 
     With the first embodiment, pass through terminals are not used. Typical routing includes input of battery power from a stud or connector, distributed through a buss bar, through the plug-in device (fuse or relay), through a fork terminal to the upper printed circuit board  23 , upper printed circuit board trace to an interconnect pin, down through the interconnect pin  52 , through a trace on the lower printed circuit board  24  to the output connector blade. With the second embodiment, pass through terminals are used. Typical routing includes input of battery power through a printed circuit board mounted stud, through a printed circuit board trace to a fork terminal, through the plug-in device (fuse of relay), and down through the pass through terminal to the output connector. In some applications the pass through terminal may be mechanically and/or electrically connected to the PCB in order to send current to another device or pin. An electrical connection to the PCB can be by, but not limited to, soldering, mechanical contact with another terminal or mechanical contact with the PCB conductive material. In another application where the pass through terminal may be used to assist in assembly or function as a terminal, the pass through terminal may be physically mounted to and only contact the non-conductive material of the PCB. 
     With the first embodiment which utilizes two printed circuit boards  23 ,  24 , Tyco 40-way connectors or any other connectors which satisfy the requirements for the outputs in the entire Power Distribution Center design can be used. The second embodiment can use any connector which satisfies the requirements for the outputs in the entire Power Distribution Center design. However, because the second embodiment has only one printed circuit board  21 A, pass through terminals can be used. To obtain the benefit obtained with the use of pass through terminals, the connector used should have the same pitch as the top plate. 
     With the first embodiment, interconnect pins  52  are required between the printed circuit boards  23 ,  24  and, therefore, assembly and soldering can be difficult. With the second embodiment interconnect pins  52  are not required and assembly and manufacture is simplified. 
     With the first embodiment, the printed circuit board assembly uses fork terminals, interconnect terminals, and connector blade terminals. With the second embodiment, the printed circuit board assembly uses fork terminals and connector blade terminals. When a pass through terminal is used, the corresponding fork terminal and connector blades terminals are not used. 
     If the height of the assemblage is important, the second embodiment should be considered because it has only one printed circuit board  21 A and does not use interconnecting pins  52 , the absence of which contributes to a reduction of height. 
     In some applications the PCB can be connected to electronic devices which may or may not be surface mounted to the PCB. These devices can provide many functions that can include, but not limited to the switching of power, protection of devices, diagnostic capability and/or network transmissions over a bus to another module or switch where the network utilized can be, but is not limited to CAN, LIN, BSS, etc. Any of these components can be mounted on either PCB of the first embodiment and/or on either side of the PCB of the first embodiment, or they can be mounted on either side of both sides of the PCB of the second embodiment. In another embodiment, see  FIGS. 5F and 5G , the components can be mounted on a supplemental circuit board assembly  100  which can be positioned adjacent to the PCB of the first or second embodiment. 
     In another embodiment, see  FIG. 5H , the Power Distribution Center can have plug-in modules  200  which may be provided to add to the electronic capability of the entire assemblage without being soldered to the PCB of the first or second embodiment. 
     A modular housing assemblage encases the power buss  10  and the printed circuit boards  23 ,  24 ; or the single printed circuit board  21 A shown in  FIG. 5E , and the housing provides receptacle portions for engaging electrical devices and I/O connectors for electrical systems. Referring to  FIGS. 6A-6B , the modular housing includes an insulating upper face  27  including at least one plate  26  having a grid of receptacle portions  28  defined through the face of the plate  26  that provide sites for electrical connection to the device interface buss  13 . 
     The plates  26  have dimensions which allow them to be used as repeatable units, where the width and the length of the upper face  27  can be adjusted by adding or removing the plates  26  in reversible interlocking fashion to correspond to the required electrical devices and electrical system connector layout, as depicted in  FIG. 6A . The plates are composed of an insulating material such as an insulating plastic.  FIG. 6B  shows the cavity portions  28  that are formed through the plates  26  of the upper face  27  and which are configured in a grid for receiving the contacts of electrical devices for connection through contacts located in the cavities to the underlying device interface bus. The electrical devices can be selected from the group consisting of fuses, relays, resistors, diodes, and switches. The grid of cavity portions  28  can be configured to receive various electrical devices which can include but is not limited to 280 devices. Thus the cavity portions  28  in the plates  26  can be configured to receive fuses, relays, etc., either separately or in combination with 280 series components where the cavities are spaced to allow a device to bridge a seam between two adjacent plates  26 . Thus, with this structure, a component such as a fuse which has two blades, can be positioned to span a seam between two adjacent plates  26  where one blade of the fuse is located in a cavity portion  28  on one plate  26  and the other blade of the fuse is located in a cavity portion  28  on an adjacent plate  26 . 
     The edges of each plate  26  further include interlocking tabs  29 , having a triangular geometry, for engaging interlocking tabs  29  on an adjacent plate  26  in reversible interlocking engagement. The interlocking tabs  29  may also be referred to as interlocking dovetails. It is noted that although the interlocking tabs  29  are shown as having a triangular geometry, other geometries are within the scope of the present invention.  FIGS. 8A and 8B  shows one embodiment of an upper face  27  that is an assemblage of four reversibly interlocking plates  26 . 
       FIGS. 7A and 7B  show perspective views of a plurality of modules of the modular housing, which includes at least one connector module  30 A having at least one socket  31 A, and at least one module  30 B having at least one socket  31 B. The sockets  31 A,  31 B are configured to correspond to the I/O connections of the printed circuit board. Referring to  FIG. 7A , the connector modules  30 A of the lower modules may have a length L 2  and width W 2  equal to the length L 1  and width W 1  of the repeatable plate  26  of the upper face  27 . In another embodiment, the connector module  30 A of the lower modules  55  may have a width equal to half the width W 1  of the repeatable plate  26  of the upper face  27 ; yet have a length equal to the length L 1  of the repeatable plate  26  of the upper face  27 . It is noted that other dimensions for the connector modules  30 A, have been contemplated, where the dimensions of the connector modules  30 A are selected to provide a repeatable unit that is compatible in a housing assembly with the repeatable plate  26  of the upper face  27 . Similar to the upper plate  26  of the upper face  27 , the connector modules  30 A, include interlocking tabs for engaging adjacent connector modules in reversible interlocking engagement, as shown in  FIG. 7B . 
     Referring to  FIG. 7A , the connector modules  30 A and modules  30 B may include at least one socket  31 A and/or  31 B, respectively. The socket  31 A of the connector module  30 A can have a geometry that accepts a 14.5 mm power blade connector, as shown in  FIG. 7C . In another embodiment the socket  31 B of the connector module  30 B can have a geometry that provides up to four different polarities and may be referred to as a 40-way connector module, as shown in  FIG. 7D .  FIGS. 8A and 8B  show the assemblage of the upper face  27  and lower connector modules  55  of the modular housing with the modular power buss  10  and printed circuit boards  23 ,  24 . In another embodiment, and as noted above, a single printed circuit board can be substituted for the two printed circuit boards. There is no limitation to the size of the connector or the number of connectors that can be connected to any one individual connector plate provided the component or components fit within the designated area. 
       FIG. 9A  shows a side cross sectional view of the modular housing sidewalls  33 . The sidewalls  33  of the modular housing can include interior guide rails  34  (which may also be referred to as slots) that provide support for the edges of the modular housing&#39;s upper face  27 , lower modules  55 , and the printed circuit boards  23 ,  24 , or a single printed circuit board  21 A as shown in  FIG. 5E . The sidewalls  33  may also include an exterior guide rail  35  to facilitate assembly of the modular housing. The sidewalls  33  can be composed of an extruded plastic, stamped or extruded metal or any other material, where the profile of the sidewall is selected to provide interior and exterior guide rails  34 ,  35 . Referring to  FIG. 9B , the sidewalls  33  of the housing may be cut at the point of assembling the modular power distribution center, where the length of the rails are selected to correspond substantially to the upper  27  and lower modules  55  of the housing, as well as the electrical device and electrical system connector layout. 
     Referring to  FIGS. 9B and 9C , the sidewalls  33  of the housing include sidewalls  33 A each having a relatively long length and sidewalls  33 B each having a relatively short length. The sidewalls  33 A,  33 B may be connected by a corner connector  36  (shown in more detail in  FIG. 9C ) having a geometry for engaging the sidewalls&#39;  33 A,  33 B profiles, where the corner connector  36  engages the exterior guide rails  35  of the sidewalls  33 . The corner connector  36  can be composed of a molded material, such as plastic, a cast structure, etc. Alternatively, as opposed to a corner connector  36  which is positioned at each corner of the housing, as shown in  FIGS. 9B and 9C , two end caps  63  as shown in  FIGS. 9D and 9E  can be positioned at opposing ends of the housing. Provisions such as mounting brackets  64  for mounting the entire device can be integrated into the end caps or guide rails.  FIG. 9D  is a perspective view of the outside surface of the end cap, and  FIG. 9E  is a perspective view of the inside surface of the end cap. 
       FIGS. 10A-10C , show an assembled modular distribution center  200 .  FIG. 10A  shows the sliding engagement of the upper face and lower face  27 ,  29  of the modular housing and two printed circuit boards  23 ,  24  in modular housing sidewalls  33 A,  33 B.  FIG. 10B  shows a side cross section view of a power distribution center  200 .  FIG. 10C  shows an assembled modular distribution center  200  having electrical devices  40 , including but not limited to relays, fuses and circuit breakers, electrically connected to the device interface buss of the modular power distribution center  200  through the receptacle portions of the modular power distribution center&#39;s upper face. In another embodiment, the side extrusions can be snapped onto the top and bottom plates. In addition, the device interface buss can be replace with other types of device interfaces as for example, fork terminals, blade terminals, receptacle terminals, etc. 
     The modular power distribution center  200  and method for distributing electrical power advantageously allows for the use of mechanical connectors which eliminates the need for heavy gauge wire routing. The present invention further provides an easily adjustable system of modular device bussing (also referred to as primary bussing), which eliminates the need for customized buss bars. Additionally, the modular plates  26  and connectors  30 A,  30 B that provide the upper and lower faces  27 ,  29  of the housing in combination with the adjustability of the primary buss  10  provides a flexible platform that improves efficiency in electrical system connector and device placement. The plastic or metal, such as aluminum sidewalls advantageously provide continuous mounting surfaces for the upper and lower faces of the modular housing as well as the printed circuit board or boards encased within the housing. Further, the integration of printed circuit boards allows for adjustments in the routing of electrical devices and connecting structures without requiring substantial changes in tooling. 
     While there has been described herein the principles of the invention, it is to be clearly understood to those skilled in the art that this description is made only by way of example and not as a limitation to the scope of the invention. Accordingly, it is intended, by the appended claims, to cover all modifications of the invention which fall within the true spirit and scope of the invention.