Juniper MX204 - Connect Power to DC Router

Figure 18: Connecng an AC Power Cord to an MX204 AC Power Supply
Connect Power to a DC Router
Table 8: MX204 DC Power System Input Voltage
Item Specicaon
DC input voltage Operang range: –44 through –72 VDC
1. Switch o the dedicated customer-site circuit breakers. Ensure that the voltage across the DC
power source cable leads is 0 V and that there is no chance that the cable leads might become
acve during installaon.
2. Remove the clear plasc cover protecng the terminal on the faceplate.
3. Verify that the DC power cables are correctly labeled 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 –48V and RTN DC cables
to chassis ground:
• The cable with very large resistance (indicang an open circuit) to chassis ground is –48V.
• The cable with very low resistance (indicang a closed circuit) to chassis ground is RTN.
4. Remove the screws from the terminals.
5. Secure each power cable lug to the terminal with the screw (see Figure 19 on page 22). Apply
between 5 lb-in. (0.6 Nm) and 6 lb-in. (0.7 Nm) of torque to the screw. Do not overghten the nut.
(Use a number Phillips 2 screwdriver.)
a. Secure the posive (+) DC source power cable lug to the RTN (return) terminal.
b. Secure the negave (–) DC source power cable lug to the –48V (input) terminal.
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