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Table Of Contents
Electrical Power for AC-Powered Nodes
Electrical Power for DC-Powered Switches
Seismic Anchoring for a Cisco Rack
Making the Frame Bonding Ground Connection for a Cisco-Supplied Rack
Using the Electrostatic Wrist Strap
Installing Multiple Cisco Units in the Same Rack
Site Preparation
This chapter describes the procedures and considerations for installing the MGX 8950 modules in an open rack or in a Cisco closed rack. For specifications on the enclosure and power system, see Appendix A, "System Specifications."
Note
If the switch arrives in a Cisco closed rack, your initial concerns should be the cabinet grounding, power connections, and optional seismic stability plate.
Parts Checklist
Before proceeding with the installation, verify that all the ordered parts are present and in good condition. Store a record of the parts and serial numbers. If any parts are missing or damaged, contact your sales representative.
Card Slot Locations
Slots 7 and 8 are reserved for the primary and redundant Processor Modules (PXM45/Bs) and slots 9, 10, 25, and 26 are reserved for the switch modules (XM-60s). These slot reservations reflect a redundant configuration for these cards. The maximum number of slots that remain for service modules is 12.
Environment
In addition to the grounding and power requirements that are detailed in the subsequent sections of this chapter, the following environmental considerations must be observed when installing an MGX 8950 node.
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The location of the switch should accommodate the routing of cables and the termination of telephone or carrier circuits. Cisco recommends raised flooring with sufficient space under the flooring to accommodate cables and wiring.
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An MGX 8950 switch requires access space around the cabinet. The suggested clearance at the front and the back of the cabinet is 30 inches. The suggested clearance on each side of the cabinet is 12 inches (30.48 cm).
DC-powered switches occupy 29.75 inches (75.69 cm) of vertical space.
AC-powered switches occupy 35.00 inches (88.90 cm) of vertical space.
AC-powered switches, with a redundant AC power supply, occupy 40.25 inches (102.23 cm) of vertical space.
Note
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For AC-powered systems, Cisco provides a 10 ft. (3 meter) power cord.
For DC-powered systems, the customer or installer must supply the power source wiring. The wire size should be 6 AWG (10 square millimeters).•
In service areas outside the United States, telecommunication rules for private networks that are connected to public networks may require that the screws, bolts, and nuts that are used to secure cabling be tightened to the degree that it requires a tool to remove them.
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The environmental temperature must be between 32 to 104°F (0 to 40°C) for normal operation. The recommended temperature is 20 to 30°C. The switch can run at up to 50°C for up to 72 hours.
The humidity must not exceed 85% relative humidity, noncondensing.
An AC-powered MGX 8950 node dissipates up to 14,300 BTUs (4200W).
A DC-powered MGX 8950 node dissipates up to 12,300 BTUs (3600W).•
The switch cannot withstand shocks greater than 10 G for 10 milliseconds at 1/2 sine wave or vibrations greater than 1/4 G at 20 to 500 Hz.
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You may purchase a stability plate to bolt a Cisco-supplied cabinet to the floor. Instructions for installing the stability plate are in the " Seismic Anchoring for a Cisco Rack" section in this chapter.
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An AC-powered switch can weigh up to 300 lb (136 kg).
A DC-powered switch can weigh up to 200 lb (90 kg).
Caution
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The building should provide enough grounding to prevent damage from electrostatic discharge. For details, see Appendix D, "Earthing/Bonding Recommendations".
Note
Power and Grounding
This section describes the requirements for electrical power and grounding at the switch and the site. These requirements apply to Central Office (CO) and Private Enterprise (PE) sites.
Electrical Power for AC-Powered Nodes
The MGX 8950 AC power requirement is 220 VAC (180 to 254 VAC). See also Appendix A, "System Specifications." The AC power source must be within 6 ft (1.8 m) of the system and easily accessible.
Both AC-powered and DC-powered MGX 8950 switches must be installed in a restricted access location. In the United States, restricted access is defined in Articles 10-116, 10-117, and 10-118 of the National Electrical Code ANSI/NFPA 70.
Before turning on the power, verify that the power supplied to the node comes from a dedicated branch circuit.
Caution
Caution
The power receptacles to which the node connects must be of the grounding type. The grounding conductors that connect to the receptacles should connect to protective earth at the service equipment. For reference, Figure 3-1 shows the hookup schematic in the three-wire wall plug.
Cisco can provide AC power cords with the following plugs:
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Figure 3-1 Schematic of AC Plug Wiring
AC Power Circuit Breakers
AC power sources must be a dedicated AC branch circuit. Each branch circuit must be protected by a dedicated two-pole circuit breaker. The circuit breakers at the source must have a rated trip delay time greater than those of the MGX 8950 circuit breaker with a medium trip delay. The MGX 8950 switch uses a 30A, 2-pole circuit breaker for each AC input. Cisco recommends that the site have a 30A, 2-pole AC circuit breaker with a long trip delay at each branch circuit.
Electrical Power for DC-Powered Switches
The DC-powered version of the MGX 8950 uses one or two Power Entry Modules (PEMs) for connection to DC power source. Each DC PEM has two 50A service connections that must be connected to the same battery source. Each branch circuit should have a 50A circuit breaker at the source. Wires connecting the PEMs to the sources should be capable of carrying 50A. A 6 AWG (10 square millimeters) copper wire is recommended. Consult the local or national codes for conductor sizing for DC supply connections if necessary.
Be sure to connect the grounding wire conduit to a solid earth ground. Cisco recommends a ring terminal lug to terminate the ground conductor at the ground stud. For details, see Appendix D, "Earthing/Bonding Recommendations".
Warning
Additional requirements are as follows:
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DC Power Circuit Breakers
DC-power sources must be a dedicated DC branch circuit. Each branch circuit must be protected by a dedicated circuit breaker. The circuit breaker must have a rated trip delay time greater than those of the MGX 8950 circuit breaker. DC-powered nodes use a 50A, 2-pole circuit breaker with a short trip delay on each -48V input. Cisco Systems recommends that the site have a dedicated 50A, 2-pole circuit breaker with a medium trip delay at each branch circuit.
Seismic Anchoring for a Cisco Rack
This section describes how to install the Cisco cabinet with the optional stability plate for seismic anchoring. If you have no stability plate, go to Chapter 4, "Enclosure and Card Installation."
Perform the following steps to set up the Cisco cabinet with the stability plate:
Step 1
Step 2
Step 3
Step 4
Figure 3-2 Stability Plate Dimensions
Figure 3-3 Installing a Cisco-Supplied Rack over the Stability Plate
Making the Frame Bonding Ground Connection for a Cisco-Supplied Rack
This section describes the steps for making ground connections that comply with Cisco grounding policies. The descriptions cover optional ground connections from each node to the ground connector of the rack, as well as the equalization connections between racks that are part of the earth grounding network.
The Cisco-supplied cabinet has two pairs of grounding studs and the hardware for securing a ground conductor to the studs at the top and bottom of the cabinet. The studs measure 1/4 inch by 20 threads per inch. The studs can accept a two-holed grounding connector designed to prevent rotation and possible loosening of the connector. Figure 3-4 shows the Cisco cabinet with the ground attachment studs in the upper and lower parts of the cabinet. A ground symbol on the Cisco rack indicates the points of attachment.
Caution
Making Cisco Cabinet Ground Connections
Perform the following steps to attach a ground conductor to the frame of a Cisco rack:
Step 1
Step 2
Step 3
Step 4
Figure 3-4 Frame Bonding Connection in Cisco-Supplied Rack
Using the Electrostatic Wrist Strap
The MGX 8950 switch ships with a wrist strap for grounding the user and protecting the electronic components from electrostatic shock. The wrist strap kit consists of a strap, a coiled cord, and a clip for holding the strap. Cisco recommends that you install the base of the wrist strap cable on the left front flange of one of the units at a convenient height.
Perform the following steps to attach the electrostatic wrist strap:
Step 1
Step 2
Step 3
Installing Multiple Cisco Units in the Same Rack
Different Cisco products may reside in the same rack. If a multisystem rack includes an MGX 8600 series switch, install the MGX 8600 series switch as the bottom unit.
