Juniper EX4300 Series Hardware Manual page 213

NOTE: The DC power supply has five terminals, two positive terminals labeled V+ and two
negative terminals labeled V–, for connecting the power supply to a dedicated DC power
source by using the DC power source cables labeled positive (+) and negative (–), and one
terminal for connecting the power supply to earth ground (see
V+ terminals are shunted internally together, as are the V– terminals to provide parallel
current path.
8. Connect one end of the grounding cable to a proper earth ground, such as the rack in which the
switch is mounted.
9. Place the grounding lug attached to the grounding cable over the earth ground terminal. The
protective earth ground terminal on an EX4300 switch, mounted on four posts of a rack, is
accessible through the slot on the mounting bracket on the left side only. If you are unable to
access protective earthing terminal, you can connect the grounding cable to the earth ground
terminal on the DC power supply.
10. Secure the grounding lug to the protective earthing terminal with the washers and screws.
11. Dress the grounding cable and ensure that it does not touch or block access to other switch
components.
WARNING: Ensure that the cable does not drape where people could trip over it.
12. Connect each power supply to the power source. Secure power source cables to the power
supplies by screwing the ring lugs attached to the cables to the appropriate terminals by using the
screw from the terminals (see
• To connect a power supply to a power source:
a. Secure the ring lug of the positive (+) DC power source cable to one of the + terminals on the
DC power supply.
b. Secure the ring lug of the negative (–) DC power source cable to the – terminal adjacent to
the + terminal that you connected to on the DC power supply.
c. Connect the ground wire to earth ground if the switch is not in a grounded rack. The
protective earth ground terminal on an EX4300 switch, mounted on four posts of a rack, is
accessible through the slot on the mounting bracket on the left side only. If you are unable to
access protective earthing terminal, you can connect the grounding cable to the earth ground
terminal on the DC power supply.
d. Tighten the screws on the power supply terminals until they are snug by using the
screwdriver. Do not overtighten—apply between 5 lb-in (0.56 Nm) and 6 lb-in (0.68 Nm) of
torque to the screws.
Figure 69 on page 204).
Figure 69 on page 204). The
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