A power line rail assembly for an electrical distribution system, comprising: a line bus bar assembly for supplying electrical energy, the line bus bar assembly having conductors including a first line bus and a separate second line bus , the first line bus including two branching first bus bars , the second line bus including two branching second bus bars , and an enclosure for housing conductors of the line bus bar assembly, characterized in that the enclosure includes first and second sets of windows on opposite sides of the enclosure through which to connect to the first and second pairs of bus bars respectively in the enclosure , the first and second bus bars are separated from each other in an X-formation along a length of the line bus bar assembly to provide first and second pairs of separated bus bars, the first pair of separated bus bars having one of the first bus bars positioned above one of the second bus bars , the second pair of separated bus bars having the other of the first bus bars positioned below the other of the second bus bars , each of the first and second sets of windows has a top row of windows and a bottom row of windows, the top and bottom rows arranged along a length of the enclosure , the top row of windows of the first set for connecting to one of the first and second bus bars of the first pair of separated bus bars, the bottom row of windows of the first set for connecting to the other of the first and second bus bars of the first pair of separated bus bars, the top row of windows of the second set for connecting to one of the first and second bus bars of the second pair of separated bus bars, and the bottom row of windows of the second set for connecting to the other of the first and second bus bars of the second pair of separated bus bars. a line bus bar assembly for supplying electrical energy, the line bus bar assembly having conductors including a first line bus and a separate second line bus , the first line bus including two branching first bus bars , the second line bus including two branching second bus bars , and an enclosure for housing conductors of the line bus bar assembly, characterized in that the enclosure includes first and second sets of windows on opposite sides of the enclosure through which to connect to the first and second pairs of bus bars respectively in the enclosure , the first and second bus bars are separated from each other in an X-formation along a length of the line bus bar assembly to provide first and second pairs of separated bus bars, the first pair of separated bus bars having one of the first bus bars positioned above one of the second bus bars , the second pair of separated bus bars having the other of the first bus bars positioned below the other of the second bus bars , each of the first and second sets of windows has a top row of windows and a bottom row of windows, the top and bottom rows arranged along a length of the enclosure , the top row of windows of the first set for connecting to one of the first and second bus bars of the first pair of separated bus bars, the bottom row of windows of the first set for connecting to the other of the first and second bus bars of the first pair of separated bus bars, the top row of windows of the second set for connecting to one of the first and second bus bars of the second pair of separated bus bars, and the bottom row of windows of the second set for connecting to the other of the first and second bus bars of the second pair of separated bus bars. <EOS>