# Cabling the Router for Power

After you have correctly cabled the SRP IOA, you must attach grounding and electrical wires before you attempt system power-up. See Figure 27.

Three main tasks are involved:

1. Switch all router power switches to OFF.

   | Caution: Switches may have inadvertently flipped to ON during shipping and installation.

2. Connect the grounding wires to the chassis.

   | Warning: Always connect the grounding wires first (before connecting the power cables) and disconnect them last when installing or servicing the router.

3. Connect the power cables to the PDUs.

See System Specifications for the power requirements for the router. Table 8 identifies the cabling requirements.

Table 8: E320 Router PDU Cables and Wires Needed

Cable/Wire | From | To
--- | --- | ---
One 6-AWG ground wire | PDU ground terminal | Termination ground
Two 4-AWG wire leads | PDU Power A –48 VDC and RTN leads | Appropriate leads on power source No.1
Two 4-AWG wire leads | PDU Power B –48 VDC and RTN leads | Appropriate leads on power source No.2

Figure 27 shows the main components of a PDU.

Figure 27: PDU

## Task 1: Turn Off All Router Power

Before starting to cable the router, push all router power switches to OFF to turn off the router.

## Task 2: Connect the Grounding Cables

The router has two grounding studs located in the rear of the chassis, near the power inputs. Each stud provides grounding for a single power unit.

To ground each power unit:

1. Locate the grounding studs on the router (Figure 27).
2. Remove the nuts and locking washers from the grounding studs.

   | Note: We recommend a minimum of 6-AWG ground wire with a ring-style terminal.

3. Place the grounding cable lead on one of the grounding studs and tighten the nuts to secure the connection.
4. Connect the other end of the ground cable to the appropriate ground termination lead.
5. Repeat Steps 3–4 for the remaining grounding stud.

   | Note: When grounding the router, leave a service loop in the grounding cable to ensure that the grounding cable is the last cable to disconnect from the shelf if strain is placed on the electrical cables.

## Task 3: Connect the Power Cables

To connect power cables to the router, follow these steps. See Figure 27 as needed.

| Note: Juniper Networks has qualified an AC power supply unit for use with the router. Contact your account representative for more information.

| Warning: Before you begin this procedure, be sure the power source is turned off, the router is turned off, and proper grounding wires are attached.

1. Be sure you have completed Task 1: Turn Off All Router Power and Task 2: Connect the Grounding Cables.
2. If applicable, loosen the screws from the clear power input module cover and remove it.

   | Warning: The wiring color code of the power cables depends on the color coding of the DC power source installed at your site. Color code standards for DC wiring do not exist. To ensure that the correct polarity is connected to the router power units, confirm the connection of the power cables to the + (positive) and – (negative) leads at the power source.

   | Note: Loosen the top and bottom thumbscrews (using a No. 2 Phillips screwdriver, if necessary)

3. Remove the nuts and locking washers from the posts for the power input (A or B) using a small insulated adjustable wrench.
4. Place one negative (neutral) cable lead on the post labeled –48 VDC.
5. Replace the locking washers and nuts, and tighten the nuts to secure the connection.
6. Place the other cable lead on the post labeled RTN.
7. Replace the locking washer and nut, and firmly tighten the nut to secure the connection.
8. Attach the opposite end of Power A's wire leads to the appropriate leads on your power source.

   | Note: To provide redundancy, do not use the same power source for Power A and Power B leads.

9. Place the clear plastic guard over the terminal posts, and secure it in place by tightening the four screws.
10. Repeat Steps 1–9 for each power input module in your configuration.