# Rack-Mounted Installation

We recommend that you use a standard EIA distribution rack. See Equipment Rack Requirements for detailed rack information.

## Installation Guidelines

Before installing the systems in a rack, consider the following guidelines and refer to Figure 15:

- You can install up to 3 ERX14xx models, 6 ERX7xx models, or 14 ERX310 routers in a single 7-ft. (2.1 m) rack.

  Installing multiple systems in a single rack enables you to maximize your available space.

- You can install an ERX14xx model, an ERX7xx model, and an ERX310 router together in the same rack. (See Figure 15.)

  | Caution: If you install an ERX7xx model or ERX310 router directly above an ERX14xx model in the same rack, you must install a plenum between the ERX7xx model or ERX310 router and the ERX14xx model so that the air can circulate between the systems. (See Figure 53.) This plenum is available from Juniper Networks.

  If you install an ERX14xx model above an ERX7xx model or ERX310 router, there is no need to install a plenum between the units because the ERX7xx models and ERX310 routers vent air out the side of the chassis.

- Install heavier systems, such as an ERX14xx model, on the bottom of the rack. Mount lighter systems, such as the ERX310 router, higher in the rack.

  Figure 15: ERX Routers Installed in Recommended Order

## Safety Guidelines

Observe the following safety guidelines when mounting the router in a rack.

| Warning: Install equipment in the rack from the bottom upward. This helps to maintain the stability of the rack and reduces the chance of the rack tipping over.

| Warning: Three people are required to install the router in a rack: two to lift the system into position and one to screw it to the rack.

| Caution: Evaluate the overall loading of the branch circuit before you install any equipment into a rack.

| Warning: Connect the router or rack to ground (earth), and ensure that a reliable grounding path is maintained in the rack.

| Warning: Do not work on the system or connect or disconnect cables during lightning activity.

| Warning: Be sure circuit breakers for the power source are in the OFF position before attaching power cables.

| Warning: Before servicing the router, turn off the power.

| Warning: Remove jewelry (including rings, necklaces, and watches) before working on equipment that is connected to power lines. Metal objects heat up when connected to power and ground and can cause serious burns or become welded to the terminals.

| Warning: Do not insert any metal object, such as a screwdriver, into an open slot or the backplane. Doing so can cause electric shock and serious burns.

| Warning: The ERX310 router AC model has more than one power-supply cord. Disconnect two power cords before servicing to avoid electric shock.

## Preparing the Equipment Racks

Following your installation plan, use a tape measure and marking pen to measure and mark space on each equipment rack for each router component. For horizontal spacing, follow Network Equipment Building System (NEBS) requirements. If you choose not to install a plenum, be sure to include 2 U of space between each chassis for proper exhaust. A plenum, however, is highly recommended.

## Installing the Router

To complete the installation of the router in a rack, you need:

- A No. 2 Phillips screwdriver
- Depending on the router, up to eight 10-32 x 3/8 Phillips screws (provided with the router) for each router to be installed

  | Warning: Three people are required to install the router in a rack: two to lift the system into position and one to screw it to the rack.

  | Caution: Make sure all persons handling a router wear an antistatic device.

To install the router in the rack:

1. With one person standing on the left side of the router and another standing on the right side, lift the router into the rack.
2. Position the router in its designated location in the equipment rack. Make sure the holes of the mounting brackets align evenly with the holes of the equipment rack on both sides.
3. Starting at the bottom, have the third person secure the router in the equipment rack by using the 10-32 x 3/8 Phillips screws.
4. Connect the necessary cables. (See Cabling ERX Routers for instructions on installing the cables.)

Figure 15 illustrates a distribution rack with one ERX310 router, one ERX7xx model, and one ERX14xx model installed.