Juniper MX10016, Hardware Manual

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Figure 86: Removing the Plastic Cable Cover
6. Remove the nuts from each DC power supply input terminal, using the 13/32 in. (10 mm) nut driver
or socket wrench to loosen the nuts.
7. Ensure that the power source circuit breaker is open so that the voltage across the DC power source
cable leads is 0 V, and that the cable leads do not become active while you are connecting DC power
supply.
8. Verify that the DC power cables are correctly labeled before connecting them 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 high resistance (indicating an open circuit) to chassis ground is negative (–) and
must be connected to the –48V (input) DC power input terminal.
•
The cable with very low resistance (indicating a closed circuit) to chassis ground is positive (+) and
must be connected to the RTN (return) DC power input terminal.
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