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Replacing an M7i DC Power Cable

 

On a DC-powered router, the power cables from the external DC power sources connect to field-wiring terminals on each power supply.

Removing an M7I DC Power Cable

Before removing a DC power cable from an M7i router with only one power supply, you must power off the router. To remove a DC power cable from the router:

  1. Shut off the power flowing from the external power sources, so that the voltage across the leads of the power cables is 0 V. Ensure that there is no chance that the cable leads might become active during the procedure.
  2. Press the power switch on the power supply faceplate to the OFF (O) position.Note

    If you are power cycling the power supply rather than shutting it off for a time, wait at least 60 seconds after turning it off before turning it back on. If you need to power it off again, wait for at least 60 seconds after powering it on.

  3. Using a number 1 Phillips screwdriver, turn the screw on each field-wiring terminal counter-clockwise to loosen the terminal connector from around the cable lug.
  4. Remove the DC cables from the terminal connectors and from the hook located on the faceplate to the right of the field-wiring terminals.
  5. Verify that the removed DC cables are not touching or blocking access to any router components.

Installing an M7i DC Power Cable

For information about the required DC power cables, see M7i DC Power Cable and Cable Lug Specifications.

Caution

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 terminal studs on each power supply. You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity.

To install a DC power cable (see Figure 1):

  1. Verify that there is no power flowing from either external power source, so that the voltage across the leads of the power cables is 0 V. Ensure that there is no chance that the cable leads might become active during the procedure.
  2. Verify that a licensed electrician has attached a listed power cable lug to each power source cable.
  3. Loop the power cables through the hook located on the faceplate to the right of the field-wiring terminals.
  4. Depending on the type of power cable lugs used, loosen or remove the screws on the field-wiring terminals.
  5. Insert the power cable lugs into the appropriate field-wiring terminals. Using a number 1 Phillips screwdriver, turn the screw on each field-wiring terminal clockwise to secure the power cable lug. Apply between 8 lb-in. (.9 Nm) and 9 lb-in. (1.02 Nm) of torque to each screw.
    1. Insert the positive (+) source cable into the return terminal, which is labeled RTN.
    2. Insert the negative (–) source cable into the input terminal, which is labeled –48V.
  6. Verify that the DC source power cabling is correct, that the DC power cables are not touching or blocking access to router components, and that they do not drape where people could trip on them.
Figure 1: Connecting DC Power Cables
Connecting DC
Power Cables