Replacing an MX80 DC Power Supply Cable
Disconnecting an MX80 DC Power Supply Cable
 | Warning: Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position. |
To disconnect a power cable for a DC power supply:
- Switch off the dedicated customer site circuit breaker for the power supply being removed. Follow your site's procedures for ESD.
- Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cables might become active during the removal process.
- Verify that the status LED on the power supply is not lit.
- Remove the power cable from the external DC power source.
- Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
- Move the DC circuit breaker on the DC power supply faceplate to the off (O) position.
- Remove the clear plastic cover protecting the terminal studs on the faceplate.
- Remove the screw from each of the terminals. (Use a number 2 Phillips screwdriver.)
- Remove the cable lugs from the terminals.
- Carefully move the power cables out of the way.
Connecting an MX80 DC Power Supply Cable
| Warning: Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position. |
To connect a power cable for a DC power supply:
- Locate a replacement power cable that meets the specifications.
- Verify that a licensed electrician has attached a cable lug to the replacement power cable.
- Verify that the status LED is off.
- Secure each power cable lug to the terminal with
the screw (see Figure 1). Apply between 5 lb-in. (0.6 Nm) and 6 lb-in. (0.7 Nm) of
torque to screw. Do not overtighten the nut. (Use a number 2 Phillips
screwdriver.)
Caution: Ensure that each power cable lug seats flush against the surface of the terminal block as you are tightening the screws. Ensure that each screw is properly threaded into the terminal. Applying installation torque to the screw when improperly threaded may result in damage to the terminal.
Caution: The maximum torque rating of the terminal screws on the DC power supply is 6 lb-in. (0.7 Nm). The terminal screws may be damaged if excessive torque is applied. Use only a torque-controlled driver to tighten screws on the DC power supply terminals. Use an appropriately-sized driver, with a maximum torque capacity of 6 lb-in. or less. Ensure that the driver is undamaged and properly calibrated and that you have been trained in its use. You may wish to use a driver that is designed to prevent overtorque when the preset torque level is achieved.
Figure 1: Connecting Power Cables to the DC Power Supply
- Verify that the DC power cable is connected correctly, that it does not touch or block access to router components, and that it does not drape where people could trip on it.
- Replace the clear plastic cover over the terminals on the faceplate.
- Attach the power cable to the DC power source.
- Turn on the dedicated customer site circuit breaker to the power supply.
- Verify that the status LED on the power supply is lit green steadily.
- On each of the DC power supplies, switch the DC
circuit breaker to the center position before moving it to the on
( | ) position.
Note: The circuit breaker may bounce back to the off (O) position if you move the breaker too quickly.
Observe the status LED on the power supply faceplate. If the power supply is correctly installed and functioning normally, the status LED lights green steadily.
