Juniper MX10004 - Page 166

5. Remove the plasc cable cover from the power input terminals by using the Phillips (+) screwdriver,
number 2, to loosen the screws (see Figure 60 on page 156).
Figure 60: Remove the Plasc Cable Cover on a JNP10K-PWR-DC2 Power Supply
6. Remove the nuts from each DC power input terminal, using the 13/32 in. (10 mm) nut driver or
socket wrench.
7. Ensure that the power source circuit breaker is open so that the voltage across the DC power
source cable leads is 0 V. Also ensure that the cable leads don’t become acve while you connect
DC power.
8. Verify that the DC power cables are labeled correctly before making connecons to the power
supply. In a typical power distribuon scheme where the return is connected to chassis ground at
the baery plant, you can use a mulmeter to verify the resistance of the –48 V and RTN DC
cables to chassis ground:
• The cable with very high resistance (indicang an open circuit) to chassis ground is negave (–)
and will be installed on the –48 V (input) DC power input terminal.
• The cable with very low resistance (indicang a closed circuit) to chassis ground is posive (+)
and will be installed on the RTN (return) DC power input terminal.
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