Juniper ACX6160 Hardware Manual page 66

• Phillips (+) screwdriver, number 2 (not provided)
• Multimeter (not provided)
NOTE: Each power supply must be connected to a dedicated power source outlet.
To connect DC power to an ACX6160:
1. Wrap and fasten one end of the ESD grounding strap around your bare wrist, and connect the
other end of the strap to an approved site ESD point on the chassis.
2. Verify that the DC power cables are correctly labeled before making connections to the power
supply. In a typical power distribution scheme where the return is connected to chassis ground at
the battery plant, you can use a multimeter to verify the resistance of the –48V and RTN DC cables
to chassis ground:
• The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+)
and is installed on the V+ (return) DC power input terminal.
• The cable with very high resistance (indicating an open circuit) to chassis ground is negative (–)
and is installed on the V– (input) DC power input terminal.
CAUTION: You must ensure that power connections maintain the proper polarity.
The power source cables might be labeled (+) and (–) to indicate their polarity.
There is no standard color coding for DC power cables. The color coding used by
the external DC power source at your site determines the color coding for the leads
on the power cables that attach to the DC power input terminals on each power
supply.
3. Install heat-shrink tubing insulation around the power cables.
To install heat-shrink tubing:
a. Slide the tubing over the portion of the cable where it is attached to the lug barrel. Ensure that
tubing covers the end of the wire and the barrel of the lug attached to it.
b. Shrink the tubing with a heat gun. Ensure that you heat all sides of the tubing evenly so that it
shrinks around the cable tightly.
Figure 21 on page 59 shows the steps to install heat-shrink tubing.
58