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This chapter describes the power and cooling requirements for the Cisco CRS Carrier Routing System 16-Slot Line Card Chassis. It contains the following sections:
The chassis power system provides power to chassis components and is made up of two power shelves that contain power modules. Each power shelf is connected to a separate and independent power source. Input power enters the power shelves and is processed by the power modules before being distributed to the components in the chassis.
The line card chassis can be either DC or AC powered. There are two options for power systems: the fixed configuration power system and the modular configuration power system.
Fixed configuration power system consists of two power shelves, AC rectifiers or DC power entry modules (PEMs), and alarm modules. It is available in versions for DC and AC power supplies. The AC version requires either 3-phase AC-Delta or 3-phase AC-Wye input power to the power shelves. In redundant configuration, the fixed configuration power system provides power sharing per load zone. The fixed configuration power system includes SNMP MIBS and XML support.
Modular configuration power system consists of two power shelves, AC or DC power modules (PMs), and alarm modules. It is available in versions for DC and AC power supplies. However, unlike the fixed configuration power system, the AC version of the modular configuration power system requires single-phase AC input power to the power shelves; there is no 3-phase AC-Wye or AC-Delta. If you have 3-phase AC Delta or AC Wye at your equipment, a Cisco CRS 3-phase AC power distribution unit (PDU) will be required to convert 3-phase AC input power to single-phase AC input power for the power shelf. At the shelf level, the power system provides 2N redundancy; the PMs themselves provide load-share redundancy. The modular configuration power system also includes SNMP MIBS and XML support.
Note | In a modular configuration AC power system, PDU refers to the Cisco CRS 3-phase AC PDU which is required to convert 3-phase AC-Wye or AC-Delta input power to single-phase AC input power for the modular configuration AC power shelf. For further information, see Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide . |
Maximum input power requirements for line card chassis with a fixed configuration power system installed are as follows:
Maximum input power requirements for line card chassis with a modular configuration power system installed are as follows:
Note | If you have a Cisco CRS 3-phase AC PDU installed, six AC PMs are required to be installed in each modular configuration AC power shelf to maintain a balanced 3-phase power load. |
Note | These power requirements are for a fully loaded chassis with sixteen PLIMs. A chassis with fewer PLIMs uses slightly less power. However, it is a good idea to allocate this much power for each chassis to ensure that enough power is available for future system expansion. |
See Cisco CRS Carrier Routing System 16-Slot Line Card Chassis System Description for detailed information about how each power system operates and distributes power to the components in the chassis.
This section describes the power and grounding requirements you must consider when planning the site facilities for the line card chassis. In addition, see the DC Power System or the AC Power System for additional power requirements.
Note | A certified electrician should review the information in these sections to ensure that the installation site meets these requirements. For larger system configurations, consult a facilities electrical expert to understand the load that the routing system may put on the facility power plant. |
General power and grounding requirements are:
Note | Be sure to review the safety warnings in Regulatory Compliance and Safety Information for the Cisco CRS-1 Carrier Routing System before attempting to install the routing system. |
The router chassis has a safety earth ground connection in conjunction with power cabling to the fixed configuration power shelves. The chassis allows you to connect the central office ground system or interior equipment grounding system to the bonding and grounding receptacles on the router chassis, when either a fixed or modular configuration power system is installed. Two threaded ground inserts are located on top of the chassis rear (MSC) side panel to the left of the lower power shelf. The figure below shows the NEBS and grounding points on the rear (MSC) side of the chassis with a modular configuration DC power shelf installed. This grounding point is also referred to as the network equipment building system (NEBS) bonding and grounding stud. The location of the grounding points on the Cisco CRS 16-slot line card chassis is the same for both fixed and modular configuration power systems.
Note | These bonding and grounding receptacles are provided to satisfy the Telcordia NEBS requirements for bonding and grounding connections. |
1 |
Chassis ground cable |
2 |
NEBS bonding and grounding points |
Note | A 45-degree grounding lug is shown in the figure above. A 180-degree (straight) grounding lug can also be used. |
The grounding points are hidden by a cover plate. When the cover plate is removed, you can easily see the labels indicating the location of the grounding points. Two grounding points are provided; use the top grounding point for NEBS grounding purposes.
To connect the chassis to a ground connection, you must have the following:
Note | The DC return of this system should remain isolated from the system frame and chassis (DC-I: Isolated DC Return). |
The Cisco CRS 16-slot line card chassis can be configured with either a fixed or modular configuration DC-input power subsystem. The chassis power system provides the necessary power for chassis components. Site power requirements differ, depending on the source voltage used.
Each DC powered chassis contains two fixed or modular configuration DC power shelves for 2N redundancy. The power shelves contain the input power connectors.
A fixed configuration DC-powered LCC contains two DC power shelves and six DC PEMs. Each power shelf contains three DC PEMs. Input power connections from the DC power source are made to terminals at the rear of each power shelf. The power shelves and power modules are field replaceable. Each power shelf and power module has its own circuit breaker.
Observe the following guidelines for DC-powered chassis. In addition, be sure to review the requirements in the General Power and Grounding Requirements.
The below table lists the fixed configuration DC input current and voltage specifications.
Nominal input voltage |
–48 VDC North America–60 VDC European Community(range: –42 VDC to –75 VDC) |
Input line current |
50 A maximum at –48 VDC40 A maximum at –60 VDC |
Each wiring block on the DC power shelf contains two pairs of terminals, one positive and one negative, and is covered by a plastic block cover that snaps onto the power shelf and is secured by a screw.
The requirements for the DC input power and ground connections are as follows:
Caution | A certified electrician must select the appropriate DC input power cable based on standard electrical practices, such as derating factors, wiring type, operating temperatures, and so on. The electrician must verify that the cable complies with the National Electrical Code (NEC) and local codes and any guidelines in effect at the installation site. At minimum, DC input power cables must be 6-AWG or heavier and rated for 90°C (194°F) temperature or higher. |
The ground cable lug should be dual hole and able to fit over M6 terminal studs at 0.63-inch (1.60 cm) centers (for example, Panduit part number LCD2-14A-Q or equivalent). The cable lug is similar to the cable lug for the input power cable. (See the figure below.)
Note | When wiring the fixed configuration DC power shelf, be sure to attach the ground cable first. When removing the wiring, be sure to remove the ground cable last. |
The color-coding of the DC input power cables depends on the color-coding of the site DC power source. Typically, green or green and yellow indicates that the cable is a ground cable. Because no color-coding standard for the source DC wiring exists, you must ensure that the power cables are connected to the DC-input power shelf terminal studs in the proper positive (+) and negative (–) polarity.
Note | If reverse polarity occurs, the DC power module circuit breaker trips. No damage should occur because of reverse polarity protection, but you should correct the situation immediately. |
The figire below shows the DC input power connections at the rear of the power shelf. The ground cable is located on the far left on the shelf. When wiring the fixed configuration DC power shelf, be sure to attach the ground cable first. When removing the wiring, be sure to remove the ground cable last.
Note | The maximum DC current allowed is 60 A. Cisco provides 65 A circuit breaker. Size the circuit breaker appropriately based on local laws and standards. |
A modular configuration DC-powered LCC contains two DC power shelves. Each modular configuration DC power shelf is connected to up to eight DC power inputs and contains up to eight DC PMs that are field replaceable.
Observe the following guidelines for DC-powered chassis. In addition, be sure to review the requirements in the General Power and Grounding Requirements.
The figure below lists the modular configuration DC input current and voltage specifications.
Nominal input voltage |
–48 VDC North America–60 VDC European Community(range: –40 VDC to –72 VDC) |
Input line current |
40 A maximum at –48 VDC30 A maximum at –60 VDC50 A maximum at -40 VDC |
Each modular configuration DC power shelf contains eight pairs of double-stud terminals, covered by a plastic terminal block cover. To provide 2N power redundancy, one power shelf should be connected to the central office “A” power bus and the other power shelf should be connected to the “B” power bus.
The requirements for the modular configuration DC input power connections are as follows:
Caution | A certified electrician must select the appropriate DC input power cable based on standard electrical practices, such as derating factors, wiring type, operating temperatures, and so on. The electrician must verify that the cable complies with the National Electrical Code (NEC) and local codes and any guidelines in effect at the installation site. At minimum, DC input power cables must be 6-AWG or heavier and rated for 90°C (194°F) temperature or higher. |
The figure below shows the DC input power cables connected to the modular configuration DC power shelf terminal studs.
The Cisco CRS 16-slot line card chassis can be configured with either a fixed or modular configuration AC-input power subsystem. The chassis power system provides the necessary power for chassis components. Site power requirements differ, depending on the source voltage used.
Each AC powered chassis contains two AC power shelves for 2N redundancy. The power shelves contain the input power connectors.
Each fixed configuration AC-powered line card chassis requires up to 14,600 watts (14.6 kW) of AC input power when the chassis is fully loaded. Although the AC power system provides slightly less power (13.2 kW) to chassis components, the additional input power is required to accommodate the 90% efficiency of the power system.
In addition to the requirements in the General Power and Grounding Requirements, AC input power requirements are as follows:
Two versions of the AC power shelf are available for AC input power in either the Delta or Wye configuration. Each power shelf has a different Cisco part number to distinguish it from the other. All chassis have two power shelves of the same type; that is, two AC Delta or two AC Wye power shelves.
Cable accessory packages for the AC power shelves contain AC power cables for the power shelves. The power cables, which are 13 feet (4 meters) long, are not shipped preattached to the power shelves.
For additional power system details, see Cisco CSR Carrier Routing System 16-Slot Line Card Chassis System Description.
The Cisco CRS line card chassis can be ordered with AC power shelves in either the Delta or Wye configuration. Each type of power shelf has a different Cisco part number to distinguish it from the other. Both types of power shelves require 3-phase, 220-to-240 VAC input power.
The figure below shows an example of how AC Delta power is wired to the power shelf. As shown, AC Delta has four wires (three phases and a safety ground) wired into a terminal board (TB1) on the power shelf. The input-AC power is routed through a circuit breaker (CB1) to the three 4.4-kW AC rectifiers (PS0, PS1, and PS2), where it is converted into DC power (nominal 54.5 VDC, 37 ADC) and routed to the six load zones of the chassis. The load zones distribute power to the various components in the chassis through the backplane. Power supply status signals are also routed to an alarm and service processor for system communication.
The figure below shows an example of how AC Wye power is wired to the power shelf. As shown, the AC Wye configuration has five wires (three phases, neutral, and a safety ground) wired into a terminal board (TB1) on the power shelf. The input-AC power is routed through a circuit breaker (CB1) to the three 4.4-kW AC rectifiers (PS1, PS2, and PS3), where it is converted into DC power (nominal 54.5 VDC, 37 ADC) and routed to the six load zones of the chassis. The load zones distribute power to the various components in the chassis through the backplane. Power supply status signals are also routed to an alarm and service processor for system communication.
A modular configuration AC-powered LCC contains two AC power shelves and up to six AC PMs per power shelf.
In addition to the requirements in the General Power and Grounding Requirements, AC input power requirements are as follows:
Note | If you have a Cisco CRS 3-phase AC PDU installed, six AC PMs are required to be installed in each modular configuration AC power shelf to maintain a balanced 3-phase power load. |
For detailed modular configuration AC power specifications, see the Line Card Chassis Specifications.
The modular configuration AC power shelf is shipped with AC power cords. Each modular configuration AC power shelf accepts up to six power cords. Each power cord is 4.25 m in length and different plug types (pre-attached) are available, depending on the locale. AC cords are available for the following locales:
The table below lists the single-phase AC-input cord power options and Cisco product numbers for the Cisco CRS 16-slot LCC with a modular configuration AC power shelf installed. The table below also references power cord illustrations.
Locale |
Cisco Product Number |
Plug Rating |
Reference Illustration |
---|---|---|---|
North America |
CRS-AC-CAB-NA(=) |
20 A/250 VAC |
|
Europe |
CRS-AC-CAB-EU(=) |
16 A/250 VAC |
|
United Kingdom |
CRS-AC-CAB-UK(=) |
13 A/250 VAC |
|
Italy |
CRS-AC-CAB-IT(=) |
16 A/250 VAC |
|
Australia |
CRS-AC-CAB-AU(=) |
15 A/250 VAC |
Note | The BS-1363 standard rates cord sets up to a maximum of 13 A, 250 VAC for the C-21 plug. Therefore, the building circuit breaker must be 13 A maximum. Installation of the Cisco CRS 16-slot line card chassis must follow national and local electrical codes. |
Note | The AS 3112 standard rates cord sets up to a maximum of 15 A, 250 VAC for the C-21 plug. Therefore the building circuit breaker must be 15 A maximum. Installation of the Cisco CRS 16-slot line card chassis must follow national and local electrical codes. |
If you have 3-phase AC Delta or AC Wye input power at your equipment, a Cisco CRS 3-phase AC PDU will be required to convert 3-phase AC Delta or AC Wye input power to single-phase AC input power that connects directly to the rear of the modular configuration AC power shelf. The Cisco CRS PDU includes either an AC Delta or AC Wye power interface, and has power input and power output cords entering and exiting the box.
In addition to the requirements in the General Power and Grounding Requirements, AC input power requirements are as follows:
The figures below show the plugs for the power cords on the AC Delta and AC Wye PDUs respectively .
For detailed Cisco CRS Power Distribution Unit AC power specifications, see the Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide.
The airflow through the line card chassis is controlled by a push-pull configuration. As shown in the following figure, ambient air flows in at the bottom front of the line card chassis and up through the card cages until it exhausts at the top rear. The bottom fan tray pulls ambient air in from the bottom front of the chassis; the top fan tray pushes warm air out the back of the chassis. The power modules in the power shelves have their own self-contained cooling fans.
A replaceable air filter is positioned above the lower fan tray. How often the air filter should be replaced depends on the facility environment. In a dirty environment, or when you start getting frequent temperature alarms, you should always check the intake grills for debris, and then check the air filter to see if it needs replacement.
Before removing the air filter for replacement, you should have a spare filter on hand; then, when you remove the dirty filter, install the spare filter in the chassis.
1 |
Front (PLIM) side of chassis |
6 |
Power shelves (two installed) |
2 |
Air intake |
7 |
Air exhaust |
3 |
Lower fan tray |
8 |
Upper card cage |
4 |
Air filter |
9 |
Lower card cage |
5 |
Upper fan tray |
10 |
Rear (MSC) side of chassis |
The line card chassis has a maximum airflow of 2050 cubic feet per minute.