Installing a -48 Vdc Power Distribution System 165
Practice 450-1011-201
Installing Upgrade Kit NT4G13AZ (From Seven to Eight Cabinets)
This procedure describes how to expand a -48 Vdc system from seven to eight
cabinets. The kit consists of one cable (NT4G09CH A0331640), one distribution
box (NT4G13AH A0333762) and a label.
This procedure consists of removing the existing power cable #2 from the old
distribution box (to be placed in cabinet 5), and connecting the existing distribution
box (in cabinet 5) to the new distribution box with the new jumper cable. Install the
removed power cable #2 in the new distribution box. Proceed as follows. See Fig.
17-2 for the locations of the input and distribution boxes, Fig.17-5 for the wiring for
the bus bar, and proceed as follows:
(1) Power down the -48 Vdc system by moving the circuit breaker located in the
input box to the OFF position.
(2) Remove the eight screws securing the front cover plate to the distribution box in
cabinet 5.
(3) Remove the cover plate.
(4) Loosen the two screws on the strain relief on the distribution box in cabinet 5
that secure power cable #2 (NT4G09BH A0331639). This cable connects the
box in cabinet 5 to one of the power converters in cabinet 6.
(5) Loosen, but do not remove, the screw in each of the three bus bars which secure
the red, black, and white wires of the power cable #2 connecting the box in
cabinet 5 with the power converter in cabinet 6.
(6) Loosen and remove the nut and washer holding the green wire from power
cable #2 to the stud in the lower portion of the box.
(7) Remove the cable from the distribution box in cabinet 5.
(8) Insert the new power jumper cable end through the now empty strain relief in
the distribution box located in cabinet 5. Ensure that approximately 1/4-inch of
cable jacket protrudes through the strain relief and into the box.
(9) Place the ring terminal from the green wire over the stud in the lower part of
the distribution box.
(10) Place the flat washer over the ring terminal, and secure with the nut removed
previously.
