STACK OF BUS BARS FOR A POWER DISTRIBUTION SYSTEM

Abstract

A power distribution system comprising a stack of bus bars having through-hole openings arranged in end portions of each of the bars such that the stack of the bars are connectable to bars of an adjacent stack. One or more connectors pass through the holes in one of the end portions of the bars of the stack. The one or more connectors also pass through holes in one of the end portions of the bars of the adjacent stack. One of the end portions of the bars of the stacks are interleaved with one of the end portions of the bars of the adjacent stack.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/308,215, filed on Feb. 25, 2010, to Edward C. Fontana, et al. entitled, “POWER DISTRIBUTION PLATFORM;” Provisional Application Ser. No. 61/287,322, filed on Dec. 17, 2009, to Roy Davis, et al. entitled, “HYBRID ARCHITECTURE FOR DC POWER PLANTS;” and Provisional Application Ser. No. 61/287,057, to filed on Dec. 16, 2009 to Edward C. Fontana, et al. entitled, “A FLOOR MOUNTED DC POWER DISTRIBUTION SYSTEM,” which are all commonly assigned with this application and incorporated herein by reference in their entirety.

TECHNICAL FIELD

This application is directed, in general, to a power distribution system and, more specifically, to a stack of DC power bus bars for a power distribution platform and method of installing the power distribution system having such a stack of bus bars.

BACKGROUND

This section introduces aspects that may be helpful to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light. The statements of this section are not to be understood as admissions about what is in the prior art or what is not in the prior art.

Telecommunication sites are evolving into large data centers, making extensive use of many similar configurations of server equipment. The Green Grid consortium has suggested that 48VDC is the most efficient and cost effective way to power such equipment, and, provide the highest availability and reliability of reserve power in case of utility grid failure. Present DC distribution and installation practices, however, can be time consuming, have high labor costs, and require large amounts of copper cabling with its associated overhead support structures, thereby further increasing the costs of such installations.

There is a long-felt need to more efficiently install and distribute DC power to server equipment at reduced labor and material costs.

SUMMARY

One embodiment provides a power distribution system. The system comprises a stack of bus bars having through-hole openings arranged in end portions of each of the bars such that the stack of the bars are connectable to bars of an adjacent stack. One or more connectors pass through the holes in one of the end portions of the bars of the stack. The one or more connectors also pass through holes in one of the end portions of the bars of the adjacent stack. One of the end portions of the bars of the stacks are interleaved with one of the end portions of the bars of the adjacent stack.

Another embodiment provides a method of assembling the above-described power distribution system. The method comprises positioning a first one of the bars of the stack in a target location of the system and positioning a first one of the bars of the adjacent stack such that a long axis end of the first bar of the stack contacts a long axis end of the first bar of the adjacent stack and the two first bars are coplanar. The method further comprises positioning a second one of the bars of the stack on the first bar of the stack such that at least one of the holes in the one end portion of the second bar of the stack aligns with at least one of the holes in the one end portion of the first bar of the adjacent stack. The method also comprises passing at least a first one of the connectors through the aligned holes in the second bar of the stack and in the first bar of the adjacent stack.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the disclosure are better understood from the following detailed description, when read with the accompanying FIGUREs. Corresponding or like numbers or characters indicate corresponding or like structures. Various features may not be drawn to scale and may be arbitrarily increased or reduced in size for clarity of discussion. Reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a front view of an example embodiment of a power distribution system having a stack of bars of the disclosure;

FIG. 2 shows a plan view of the example power distribution system of FIG. 1 through view line 2-2 in FIG. 1;

FIG. 3 shows a detailed cross-sectional view of the power distribution system depicted corresponding to view 3 in FIG. 1.

FIG. 4 presents a front view of another example embodiment of a power distribution system having a stack of bars of the disclosure;

FIG. 5 presents a front view of still another example embodiment of a power distribution system having a stack of bars of the disclosure;

FIG. 6 presents a front view of still another example embodiment of a power distribution system having a stack of bars of the disclosure;

FIG. 7 presents a plan view of the example power distribution system depicted in FIG. 6 through view line 6-6 in FIG. 6;

FIGS. 8A and 8B present perspective views of example embodiments of the power distribution system having a stack of bars of the disclosure that are oriented edge-on;

FIG. 9A presents an overhead plan view of an example embodiment of the power distribution system having an edge-on oriented stack of bars of the disclosure configured to have a mid-procession power tap structure;

FIG. 9B presents a side view of one example embodiment of the example system depicted in FIG. 9A through view line A-A in FIG. 9A;

FIG. 9C presents a side view of another example embodiment of the example system depicted in FIG. 9A, also through view line A-A in FIG. 9A; and

FIG. 10 presents a flow diagram of an example embodiment of a method of assembling a power distribution system of the disclosure, such as any of the example systems depicted in FIGS. 1-9C.

DETAILED DESCRIPTION

The following merely illustrate principles of the invention. Those skilled in the art will appreciate the ability to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its scope. Furthermore, all examples and conditional language recited herein are principally intended expressly to be only for pedagogical purposes to aid in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to specifically disclosed embodiments and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof. Additionally, the term, “or,” as used herein, refers to a non-exclusive or, unless otherwise indicated. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

One embodiment is a power distribution system. FIG. 1 shows a front view of an example embodiment of the power distribution system featuring a stack of bus bars (e.g., DC power bus bars) of the disclosure. FIG. 2 shows a plan view of the power distribution system 100 through view line 2-2 in FIG. 1. FIG. 3 shows a detailed cross-sectional view of the power distribution system 100 corresponding to view 3 in FIG. 1.

The example power distribution system 100 depicted in FIGS. 1-3 comprises a stack 105 of bus bars 110. The bus bars 110 have through-hole openings 115 arranged in end portions 120, 122 of each of the bars 110 such that the stack 105 of the bars 110 is connectable to bars 130 of an adjacent stack 135. One or more connectors 140 pass through the holes 115 in one of the end portions (e.g., end portions 120) of the bars 110 of the stack 105. The one or more connectors 140 also pass through holes 115 in one of the end portions (e.g., end portions 125) of the bars 130 of the adjacent stack 135. The one end portion (e.g., end portions 120) of the bars 110 of the stacks 105 are interleaved with one end portions (e.g., end portions 125) of the bars 110 of the adjacent stack 135.

The term adjacent stack as used herein refers to planform adjacent stacks. That is, the first stack 110 and second stack 135 are adjacent in a planform view such as depicted in the plan view presented in FIG. 2.

In some embodiments, the connectors 140 include a threaded fastener 145 (e.g., bolt or threaded rod) and in some cases can further include one or more caps 147 attached to the fastener 145 (e.g., a nut that screws onto the bolt). Other types of connectors 140 that could be used would be apparent to one skilled in the art based upon the present disclosure.

The cross-sectional view of the example embodiment shown in FIG. 3 further illustrates aspects of the configuration of the bars 110 of two stacks 105, 135 (e.g., bars 301, 302, 303, 304 of the first stack and bars 305, 306, 307, 308 of the second adjacent stack 135). As illustrated for the embodiment shown, to maximize the lateral extension of the stacks, 105, 135, a long axis (e.g., long axis 310) of at least one of the bars 110 in the stack 105 (e.g., bar 301) can be laterally aligned with a long axis (e.g., long axis 315) of at least one of the bars 110 in (e.g., bar 305) the adjacent stack 135. As further illustrated, the ends 321, 322, 323, 324 of bars 110 (e.g., the end 321 of bar 301) of one stack is adjacent to ends 325, 326, 327, 328 of the bars 110 (e.g., the end 325 of bar 305) of the adjacent stack 135.

As further illustrated in FIG. 3, in some embodiments to facilitate the interleaved interconnection between the stacks 105, 135, the one end (e.g., ends 321, 323) of at least one pair of odd-numbered bars in the stack 105 (e.g., bars 301, 303) are aligned with each other (e.g., vertically aligned). In some embodiments the one end (e.g., ends 322, 324) of the one end of at least one pair of even-numbered bars (e.g., bars 322, 324) in the stack 105 are aligned with each other. In some embodiments, the ends (e.g., ends 321, 323, and, ends 322 and 324, respectively) of the odd and even numbered bars (e.g., bars 301, 303, and, bars 302, 304, respectively) are offset by a distance 330, 337 (e.g., a lateral distance parallel to the long axis 310 of the bar 110) that is greater than a distance 335 from at least one of the nearest-end holes 115 (e.g., holes 341) to the ends of the bars.

As further illustrated in FIG. 2, in some embodiments, to more securely connect the bars 110, 130 of different stacks 105, 135, the end portions 120, 125 of the bars 110 can have a row 210 of the holes 115, the holes 115 in the row 210 being aligned with each other in a direction that is parallel to a short axis 220 of the bar 110.

As also illustrated in FIG. 2, in some embodiments, to facilitate forming the desired interleaved interconnection of bars 110, 130, between the stacks, 105, 135, one end portion 120 of each of the bars 110 can have a different number of the holes 115 than the opposite end portion 125 on an opposite end of the same bar 110. For example, there can be one row 210 of holes 115 in one end portion 120 and two rows 210 of holes 115 in the opposite end portion 125. That is, there can be an asymmetric distribution of holes 115 in the two end portions 120, 125 each of the bars 110 to help guide one on how to interconnect the stacks 105, 135 into an interleaved stack configuration.

In other cases, however, it can be advantageous for the distribution of holes to be symmetric, e.g., to reduce the cost of manufacturer of the bars, and to provide modular bars. In some cases, for instance, it can be advantageous for the all of the bars 110 of the stack 105, or stacks 105, 135 to have a same long axis 310 length 350, short axis 220 width 355, and arrangement of holes 115.

Embodiments of the power distribution system 100 can include a plurality of stacks of bars that are interconnected in configurations analogous to that shown in FIGS. 1-3. FIG. 4 presents a front view of another example embodiment of a power distribution system 100 of the disclosure. The stack 105 of bars 110 and the adjacent stack 135 of bars 130 shown in FIG. 1 can be part of a procession 405 of interconnected stacks 105, 135, 410, 412. In some cases, the long axis 310 of at least one of the bars 110 in the stack 105 is laterally aligned with a long axis 315 of at least one of the bars 130 in the adjacent stack 110. In some cases, the long axis 310, 315, 420, 425 of at least one of the bars 110 in each of interconnected stacks 410 are laterally aligned.

In some embodiments of the system 100, the plurality of stacks can have different numbers of bars in order to distribute DC power to different components for a particular configuration of the system 100. For instance, as shown in FIGS. 1 and 3, the adjacent stack 135 can have a same number of bars 130 as the number of bars 110 in the stack 105. In other cases, however, as shown in FIG. 4, a stack (e.g., stack 410) can have lesser number of bars than the number of bars 110 than in an adjacent stack (e.g., stack 105), or a stack (e.g., stack 130) can have a greater number of bars than the number of bars in an adjacent stack (e.g., stack 412).

In some embodiments of the system 100, for ease of manufacture and installation, all of the bars 110 of the procession 405 of interconnected stacks 105, 130, 410 412 can have modular bars 110 (e.g., FIG. 4). For instance, in some cases all of the bars 110 of the procession 405 can have a same long axis length 150 (e.g., FIG. 1), short axis width 230 (e.g., FIG. 2), and arrangement of holes 115. In other cases, however, the bars can have one or more of different lengths, widths and hole distributions, as needed for a desired system 100 installation.

In some embodiments of the system 100, it is desirable to distribute the weight of the stacks of bars in a particular direction or in an even distribution. An example of such an embodiment is illustrated in FIG. 5 which presents a front view of another example embodiment of a power distribution system 100 of the disclosure.

For instance, in some embodiments, each one of the successive stacks (e.g., stack 505, stack 506, stack 507, and stack 508, respectively) in a procession 510 of interconnected stacks has at least one less bar 110 than in the preceding adjacent stack. E.g., stack 506 has one less bar 110 than stack 505, and stack 507 has one less bar 110 than stack 506. In some embodiments, the procession 510 of interconnected stacks 505, 506, 507, 508 are aligned such that the successive stacks with the at least one less bar 110 than the previous adjacent stack define a stair-step in a first direction 525.

In some embodiments, to facilitate providing an even weight distribution of bars in case where the number of bars in each stack can differ, the system 100 can further include a second procession 530 of interconnected stacks which distributes the bars in a mirror image of the first procession 510. For instance, the stacks can be aligned such that the successive stacks (e.g., stack 535, stack 536, stack 537 and stack 538, respectively) with at least one less bar 110 than the previous adjacent stack define a second stair-step in a second direction 545 that is opposite to the first direction 525 of the first procession 510.

Some embodiments of the power distribution system 100 can include additional components to complete the system 100. FIG. 6 presents a front view of another example embodiment of the system 100 which shows some example components and their configuration relative to the stack 105 of bars 110. FIG. 7 shows a plan view of the example power distribution system of FIG. 6 through view line 6-6 in FIG. 6.

As shown in FIG. 6, some embodiments of the system 100 can further include an electrical cabinet 610 that includes electrical feed connections 615 configured to receive DC power from at least one of the bars 110 of the stack 105. The electrical feed connections 615 are configured to deliver DC power to electrical components 620 (e.g., telecommunications server equipment) held within the cabinet 610. In some cases, one or more of the stacks 105 can be inside of the electrical cabinet 610. In other cases, the stack 110 can be located below the electrical cabinet 610. In still other cases the stack can be located above the electrical cabinet 610.

Some embodiments of the system 100 can further include a platform 630 configured to hold the stack 105 of bars 110. For instance, as illustrated in FIG. 6 electrical cabinet 610 can rest on the platform 630 and the stack 105 can lay on the platform 630 below the cabinet. As further illustrated in FIG. 7, the platform 630 can further include over-current protection devices 710 (e.g., fuses or circuit-beaker devices held in receptacles 715 of the platform 630), power taps 720, and electrical connections 730 each with cabinet connection contacts 735 to facilitate the delivery of DC power to the electrical feed connections 615. For instance, in some cases, a power tap 720 can be connected to at least one of the bars 110 of the stack 105 and the power tap 720 can be configured to deliver DC power to the connected bar 110, e.g., via the over-current protection device 710. In some cases one or more of the bars 110 can further include holes 740 configured to accept a connector 740 (e.g., analogous to the connector 140 desired in the context of FIG. 1) located in interior portions of the bar 110, wherein the connector 740 electrically connects the one or more bars to the one or more of the power taps 720.

Providing such a stair-step arrangement of a procession of stacks can facilitate delivering power to different cabinets 610 located above one or more of the stacks in a procession of stacks where the components 620 in the cabinet draw a high current. For instance, having the stair-step arrangement such as presented in FIG. 5 can reduce the voltage drop across the length of the entire procession 510 while minimizing the number of bars 110 used. For example, consider the case where power is fed from direction 525 and there are electrical feeds 615 to each cabinet 610 from one of the stacks 505, 506, 507 and 508. In such a case, a downward stair-step along direction 525 can help to substantially maintain the same current density in each stack from the power feed, starting at stack 505, to the last power load at stack 508. In such cases, it would be desirable to configure embodiments of a second procession 530 of stacks 538, 537, 536, 535 (e.g., carrying the return current) such that the downward stair-step is also along same direction 525 as the first procession 510.

As also illustrated in FIGS. 6 and 7, in some embodiments it is desirable for the end portions 120, 125 of the bars 110 of the stack to extend outside of the platform 630 (or outside of the cabinet 610 in other embodiments). Extending the end portions 120, 125 outside of the platform or cabinet can facilitate the interconnection of the bars 110 to other bars of adjacent stacks (e.g., stack 130 of FIG. 1), as well as facilitate inspection and maintenance of the interconnections.

Embodiments of the stack 105 of bars 110 can be oriented in a variety of directions in different embodiments of the power distribution system 100. For instance, FIGS. 8A and 8B present perspective views of example embodiments of the system 100 having a stack 105 of bars 110 (and interleaved stack 135 of bars 130 in FIG. 8A) whose long axis have horizontal and vertical orientations, respectively with respect to a floor 820, or similar structure, that supports the system 100. Additionally, the stack 105 is oriented such that one of the edges 830, 835 of the bars 110 opposes a floor that supports the stack. For instance, in some embodiments, as illustrated in FIG. 8A, a long edge 830 of the bars 110 can oppose the floor 820. In still other embodiments, as illustrated in FIG. 8B a short edge 835 of the bar 110 can oppose the floor 820.

In yet other embodiments, a face 840 of the bar 110 can oppose the floor 840. For instance, for the plan view of the embodiment depicted in FIG. 7, if the platform 630 rests on a floor, then face of the bars 110 held in the platform 630 would oppose the floor. In such embodiments, the stack 105 of bars 110 can be configured such that one bar 110 lays substantially on top of another bar 110, such as depicted in FIG. 6.

One advantage of having the stack 105 oriented edge-on such as shown in FIG. 8A or 8B is that the vertical height of the stack is not increased as more bars 110 are added to the stack 105. Another advantage is that, in some embodiments of the system 100, such an orientation can facilitate connection of the bars 110 to a power source located at an end of the stack 105 (or procession 845 of stacks; FIG. 4). For instance, as illustrated in FIG. 8B, if a power feed 850 from a power source is over the stack 105 and above the floor 820, orienting the long axis 810 of the bars 110 perpendicular to the floor 820 can facilitate connection to the power feed 850.

Still another advantage of an edge-on orientation of the stack 105 is that this orientation can facilitate tapping power into a mid-portion of a procession of stacks 105. FIG. 9A presents an overhead plan view of an example embodiment of the power distribution system 100 having a procession 905 of stacks 105, 130 with bars 110, 130 oriented edge-on similar to that depicted in FIG. 8A, and configured to have a mid-procession power tap structure 910. FIG. 9B presents a side view of one example embodiment of the example system 100 depicted in FIG. 9A through view line A-A in FIG. 9A. FIG. 9C presents a side view of another example embodiment of the example system 100 depicted in FIG. 9A, also through view line A-A in FIG. 9A.

As illustrated in FIGS. 9A-9C the power tap structure 910 can be located between two stacks 105, 135 in a procession of stacks 905 and be connected to bars 110, 130 in each of the two stacks 105, 135. In some configurations, the power tap structure 910 can facilitate connecting the stack 105 of bars 110 within a cabinet outline. For instance, in some embodiments such as depicted in FIG. 9B the power tap structure 910 can be configured as a vertical bus bar power feed. The power tap structure 910 configured as a vertical bus bar power feed can be used to connect the stack 105 or procession of stacks 905 to an over head power source. The power tap structure 910 can be introduced any where in the procession 905, e.g., to provide power to the distribution system 100 at any junction point along the procession 905. Alternatively or additionally, the power tap structure 910 can be configured as a vertical bus bar power feed, e.g., to provide a high current feed to electrical components in a cabinet. For instance, in some embodiments such as depicted in FIG. 9C, the power tap structure 910 can be configured as a tapping plate, similar to the power tap 720 such shown in FIG. 7, that connects to over-current protection devices 710 in a cabinet 610 itself or in a platform 620 connected to the cabinet 610.

Based upon the present disclosure one skilled in the art would understand how multiple the power tap structures 910, configured as vertical bus bars, tapping plates, or spacer plates, could be integrated into stacks 105, 135 of system 100. One skilled in the art would also understand, based on the present disclosure, that power tap structure 910 could be configured to have one or more bends (e.g., a 90 degree bend) to facilitate connection to other orientations of the stack 105 of bars 110, e.g., such as depicted in FIG. 7, where the face of the bars 110 opposes the floor.

Other embodiments of the cabinet, platform and other components of the system 100 that the stack 105 of bars 110 can be adapted to be used with are discussed in the above-identified provisional patent applications as well as the following non-provisional patent applications: U.S. patent application Ser. No. ______, to Edward Fontana, Paul Smith and William England entitled, “A platform for a power distribution system”; U.S. patent application Ser. No. ______ to Edward Fontana, Paul Smith and William England entitled, “A cabinet for a power distribution system”; U.S. patent application Ser. No. ______ to Edward Fontana, entitled, “A cabinet for a high current power distribution system”; U.S. patent application Ser. No. ______ to Edward Fontana and Paul Smith entitled, “Thermal extension structures for monitoring bus bar terminations,” all of which are incorporated herein in their entirety.

Another embodiment of the disclosure is a method of assembling the power distribution system. For example, the assembly can be performed at an installation site of the system 100. The method can be used to assemble any of the power distribution systems 100 discussed in the context of FIGS. 1-9C herein.

FIG. 10 presents a flow diagram of an example embodiment of selected steps in the method 1000 of assembling the power distribution system. With continuing reference to FIGS. 1-8, the method 1000 comprises a step 1005 of positioning a first one of the bars 110 of the stack 105 (e.g., bar 301) in a target location (e.g., an installation site) of the system 100. The method 1000 also comprises a step 1010 of positioning a first one of the bars 130 of the adjacent stack 135 (e.g., bar 305) such that a long axis end 321 of the first bar 301 of the stack 105 contacts a long axis end 325 of the first bar 305 of the adjacent stack 135 and the two first bars 301, 305 are coplanar. The method 1000 also comprises a step 1015 of positioning a second one of the bars 110 of the stack 105 (e.g., bar 302) on the first bar 110 of the stack 105 (e.g., bar 301) such that at least one of the holes 115 in the one end portion 120 of the second bar 302 of the stack 105 aligns with at least one of the holes 140 in the one end portion 125 of the first bar 305 of the adjacent stack 135. The method also comprises a step 1020 of passing at least a first one of the connectors 140 through the aligned holes 115 in the second bar 302 of the stack 105 and in the first bar 305 of the adjacent stack 105.

In some embodiments of the method 1000 can further include a step 1025 of positioning a second one of the bars 130 of the adjacent stack 135 (e.g., bar 306) on top of the first bar 305 of the adjacent stack 135. The positioning step 1025 is such that a long axis end 322 of the second bar 302 of the stack 105 contacts a long axis end 326 of the second bar 306 of the stack 110, the second bar 302 of the stack 105 and the second bar 306 of the adjacent stack 135 are coplanar, and, at least one of the holes 115 in the one end portion 125 of the second bar 306 of the adjacent stack 135 aligns with at least one different one of the holes 115 in the one end portion 120 of the first bar 301 of the stack 105.

Embodiments of the method 1000 can also include a step 1030 of passing at least a second one of the connectors 140 through the aligned holes 115 in the second bar 306 of the adjacent stack 135 and in the different one of the holes 115 of the first bar 301 of the stack 105.

Embodiments of the method 100 can further include repeating one or more of the positioning steps 1005, 1010, 1015, 1025 for additional bars 110 of the stack 105 (e.g., bars 303, 304) and bars 130 the adjacent stack 135 (e.g., bars 307, 308) to complete both stacks 110, 135 so as to have the interleaved end portions 120, 125.

In some cases, after the stacks 105, 135 are completed, it is preferable for the step 1020 of passing the at least first one of the connectors 140, and, the step 1030 of passing the at least second one of the connectors 140 through the aligned holes 115 from interleaved bars 110, 130 of the stacks 105, 135 to be performed.

One skilled in the art would understand that additional steps could be performed to complete the system's 100 installation. Examples of such additional steps are provided in the provisional and non-provisional patent applications cited elsewhere herein and incorporated by reference in their entirety.

Although the embodiments have been described in detail, those of ordinary skill in the art should understand that they could make various changes, substitutions and alterations herein without departing from the scope of the disclosure.

Claims

1. A power distribution system, comprising:

a stack of bus bars having through-hole openings arranged in end portions of each of the bars such that the stack of the bars are connectable to bars of an adjacent stack, wherein one or more connectors pass through the holes in one of the end portions of the bars of the stack, the one or more connectors also pass through holes in one of the end portions of the bars of the adjacent stack, and one of the end portions of the bars of the stacks are interleaved with one of the end portions of the bars of the adjacent stack.

2. The power distribution system of claim 1, wherein the connectors include a threaded fastener.

3. The power distribution system of claim 1, wherein:

the one end of at least one pair of odd-numbered bars in the stack are aligned with each other;

the one end of at least one pair of even-numbered bars in the stack are aligned with each other; and

the ends of the odd and even numbered bars are offset by a distance that is greater than a distance from at least one of the nearest-end holes to the ends of the bars.

4. The power distribution system of claim 1, wherein the end portions of the bars have a row of the holes, the holes in the row being aligned with each other in a direction parallel to a short axis of the bar.

5. The power distribution system of claim 1, wherein one of the end portions of each of the bars have a different number of the holes than in the other opposite end portion of the same bar.

6. The power distribution system of claim 1, wherein there is an asymmetric distribution of the holes one of the two end portions of each of the bars.

7. The power distribution system of claim 1, wherein all of the bars of the stack have a same long axis length, short axis width, and arrangement of the holes.

8. The power distribution system of claim 1, wherein the adjacent stack has a different number of bars than the number of bars in the stack.

9. The power distribution system of claim 1, wherein the stack of bars and the adjacent stack of bars are part of a procession of interconnected stacks.

10. The power distribution system of claim 9, wherein all of the bars of the procession of interconnected stacks have a same long axis length, short axis width, and arrangement of the holes.

11. The power distribution system of claim 9, wherein each one of the successive stacks in the procession of interconnected stacks has at least one less bar than the preceding adjacent stack.

12. The power distribution system of claim 11, wherein the procession of interconnected stacks are aligned such that the successive stacks with the at least one less bar than the previous adjacent stack define a stair-step in a first direction.

13. The power distribution system of claim 12, further including a second procession of interconnected stacks that are aligned such that the successive stacks with at least one less bar than the previous adjacent stack define a second stair step in a second direction that is opposite to the first direction.

14. The power distribution system of claim 1, further including an electrical cabinet that includes electrical feed connections configured to receive DC power from at least one of the bars of the stack.

15. The power distribution system of claim 1, further including a platform configured to hold the stack of bars.

16. The power distribution system of claim 1, wherein a power tap is connected to at least one of the bars of the stack and the power tap is configured to deliver DC power to the connected bar.

17. The power distribution system of claim 16, wherein one or more of the bars further include holes located in interior portions of the bar, and is configured to accept a connector that electrically connect the ore or more bars to one or more of the power taps.

18. The power distribution system of claim 1, wherein the stack is oriented such that one edge of the bars opposes a floor that supports the stack.

19. The power distribution system of claim 1, further including a power tap structure located between two stacks in a procession of stacks and connected to bars in each of the two stacks.

20. A method of assembling the power distribution system of claim 1, comprising:

positioning a first one of the bars of the stack in a target location of the system;

positioning a first one of the bars of the adjacent stack such that a long axis end of the first bar of the stack contacts a long axis end of the first bar of the adjacent stack and the two first bars are coplanar;

positioning a second one of the bars of the stack on the first bar of the stack such that at least one of the holes in the one end portion of the second bar of the stack aligns with at least one of the holes in the one end portion of the first bar of the adjacent stack; and

passing at least a first one of the connectors through the aligned holes in the second bar of the stack and in the first bar of the adjacent stack.