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This chapter describes Cisco CRS 8-Slot LCC Power and Cooling systems. It also provides the power, grounding, and cooling requirements for the installation site to help you plan the site facilities for the system. Cisco CRS 8-Slot LCC System Description provides detailed information about these components.
This chapter contains the following sections:
The 8-slot LCC can be either DC or AC powered. Each type of power system (DC or AC) provides power to chassis components. There are two options for power systems: the fixed configuration power system and the modular configuration power system.
Note | In a fixed configuration AC or DC power system, PDU refers to the power component that connects to the AC rectifier or DC PEM. |
Note | In a modular configuration AC power system, PDU refers to the Cisco CRS 3-phase AC PDU that converts 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, refer to Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide. |
Fixed configuration chassis input power requirements are as follows:
Modular configuration chassis input power requirements are as follows:
Note | If you have a Cisco CRS 3-phase AC PDU installed, three 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 eight PLIMs. A chassis with six or seven 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 8-Slot Line Card Chassis System Description for detailed information about how each power system operates and distributes power to components in the chassis.
This section describes the power and grounding requirements you must consider when planning the site facilities for the routing system. In addition, see DC Power Systems and AC Power Systems for additional information about the power requirements for your chassis type.
Note | A qualified 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 Carrier Routing System before attempting to install the routing system. |
The router chassis has safety earth ground connections in conjunction with the power cabling to the fixed configuration PDUs.
Note | Modular configuration power supports chassis grounding only. |
The chassis allows you to connect the central office ground system or interior equipment ground system to the bonding and grounding receptacles on the router chassis, when either a fixed or modular configuration power system is installed. Six chassis grounding points are provided at the rear (MSC) side of the chassis, as shown in the following figure. Each side of the chassis has one pair of threaded ground studs located on the inside of the chassis and two pairs of grounding receptacles located on the outside of the chassis. These ground points are also called the network equipment building system (NEBS) bonding and grounding points.
Note | These bonding and grounding receptacles satisfy the Telcordia NEBS requirements for bonding and grounding connections. |
1 |
NEBS bonding and grounding points (inside chassis) |
2 |
NEBS bonding and grounding points (outside chassis) |
To connect the chassis to a NEBS-compliant bonding and grounding system at your site, you must have the following:
Note | The chassis ground wire connectors have a torque value of 30 in.-lb (3.39 N-m). |
Caution | The DC Return of the Cisco CRS 8-slot chassis should remain isolated from the system frame and chassis (DC-I: Isolated DC Return). |
For additional information about NEBS, see Cisco CRS Carrier Routing System Regulatory Compliance and Safety Information.
The Cisco CRS 8-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 either two fixed configuration PDUs or two modular configuration power shelves for 2N redundancy. A fixed configuration DC PDU connects to a DC PEM, while a modular configuration DC power shelf connects to up to four DC PMs.
A fixed configuration DC-powered LCC contains two DC-input PDUs and two DC PEMs. Each DC PDU is connected to three DC power inputs and contains a single 7500-watt DC PEM that is field replaceable. Input DC power enters the PDU and is passed to the PEM, which provides power to the components in the chassis. Each PEM has its own circuit breaker.
In addition to the requirements described in the General Power and Grounding Requirements, DC input power requirements are as follows:
Each PDU has three pairs of double-stud terminals (RTN, –48V/–60V) for connecting DC input power. To provide 2N power redundancy, one PDU should be connected to the central office “A” power bus and the other PDU should be connected to the “B” power bus.
The requirements for the DC input power and ground connections are as follows:
Each DC input power cable is terminated at the PDU by a cable lug. The cable lugs must be dual-hole, and have a 45-degree angle tongue. They must be able to fit over 1/4-inch terminal studs at 0.625-inch (15.88-mm) centers. For example, you could terminate a 2-AWG power cable with a cable lug, such as Panduit part number LCC2-14AWH-Q (Cisco part number 32-0677-01) or equivalent, as shown in this figure.
Note | Use local electrical codes for clearance requirements when using power lugs to ensure safe operation. |
Note | DC input power cables must be connected to the PDU terminal studs in the proper positive (+) and negative (–) polarity. In some cases, the DC cable leads are labeled, which is a relatively safe indication of the polarity. However, you must verify the polarity by measuring the voltage between the DC cable leads. When making the measurement, the positive (+) lead and the negative (–) lead must always match the (+) and (–) labels on the PDU. |
The ground wire cable lug should be dual-hole, as shown in the following figure, and able to fit over M6 terminal studs at 0.625-inch (15.88-mm) centers (for example, Panduit part number LCD6-14A-L or equivalent).
This figure shows the DC input power cables connected to the DC PDU terminal studs.
1 |
Each set of cables (RTN and –48V/–60V) is a single VDC input. |
Note | When wiring the fixed configuration DC PDU, be sure to attach the ground wire first (shown above on the far left side of PDU). When removing the wiring, be sure to remove the ground wire last. |
Note | In the fixed configuration DC power system, power wires have a 20 in.-lb (2.26 N-m) torque value and ground wires have a 30 in.-lb (3.39 N-m) torque value. The PDU mounting screws have a 9 in.-lb (1.04 N-m) torque value. |
The color coding of the DC input power cable leads 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 there is no color code standard for the source DC wiring, you must ensure that the power cables are connected to the PDU terminal studs in the proper positive (+) and negative (–) polarity.
Caution | Although reverse polarity should not damage the DC power system, you should correct a reverse polarity condition immediately. |
A modular configuration DC-powered LCC contains two DC power shelves. Each modular configuration DC power shelf is connected to up to four DC power inputs and contains up to four DC PMs that are field replaceable.
In addition to the requirements described in the General Power and Grounding Requirements, DC input power requirements are as follows:
Each power shelf contains four pairs of double-stud terminals (RTN, –48V/–60V) for connecting DC input power. 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 DC input power connections are as follows:
Note | Use local electrical codes for clearance requirements when using power lugs to ensure safe operation. |
The following figure shows the DC input power cables connected to the modular configuration DC power shelf terminal studs.
Note | In the modular configuration DC power system, the power wire connectors have a torque value of 20 in-lb (2.26 N-m). |
Note | An earth ground cable is not required for the modular configuration DC power shelf. |
The Cisco CRS 8-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 fixed configuration AC PDUs or two modular configuration AC power shelves for 2N redundancy. A fixed configuration AC PDU connects to an AC rectifier, while a modular configuration AC power shelf can contain up to three AC PMs.
A fixed configuration AC-powered LCC contains two AC power distribution units (PDUs) and two AC rectifier modules. Each AC PDU is connected to an input AC power source and holds a single 7500-watt AC rectifier. Input AC power enters the PDU and is passed to the rectifier. Here, the input AC power is converted into the 54.5 VDC used to power components in the chassis. Each AC rectifier is field replaceable and has its own circuit breaker.
Two versions of the AC PDU are available to accommodate AC input power in either the Delta or Wye configuration. Each PDU has a different Cisco part number, and ships with an AC power cord that is 14 feet (4.3 m) long.
In addition to the requirements in the General Power and Grounding Requirements, AC input power requirements are as follows:
The following figures show the plugs for the AC Delta and Wye power cords.
For detailed AC power specifications, see Line Card Chassis Specifications. The following section describes the 3-phase wiring for AC Delta and Wye configurations.
This section contains a brief description of the 3-phase wiring for AC Delta and Wye configurations that facilities electricians should understand.
AC Delta and AC Wye are both basically 200 to 240 VAC input power:
The figure shows a PDU wired for AC Delta 3-phase power. As shown, input AC power is routed to three internal 2.5-kW power modules in the rectifier, where it is converted into DC power (nominal 54.5 VDC, 46 ADC) and routed to the three load zones of the chassis.
The AC Delta PDU is shipped with a 14-foot (4.3-m) AC power cord with a 4-pin L15-30P plug.
This figure shows a PDU wired for AC Wye 3-phase power. As shown, input AC power is routed to three internal 2.5-kW power modules in the rectifier, where it is converted into DC power (nominal 54.5 VDC, 46 ADC) and routed to the three load zones of the chassis.
The AC Wye PDU is shipped with a 14-foot (4.3-m) AC power cord. The power cord has a 5-pin IEC 60309 plug that is rated for 16 A (International) and 20 A (North America). It plugs into an IEC 60309 receptacle (16 or 20 A).
A modular configuration AC-powered LCC contains two AC power shelves and up to three AC PMs per power shelf.
In addition to the requirements in the General Power and Grounding Requirements section, AC input power requirements are as follows:
Note | If you have a Cisco CRS 3-phase AC PDU installed, three 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 three power cords. Each AC power cord has a different plug type, depending on locale. AC power cords are available for the following locales:
The table lists the single-phase AC-input cord power options and Cisco product numbers for the Cisco CRS 8-slot LCC with a modular configuration AC power shelf installed. Every locale listed in the table have power cord illustrations as show below.
Locale |
Cisco Product Number |
Plug Rating |
---|---|---|
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 8-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 8-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 following figures show the plugs for the power cords on the AC Delta and Wye PDUs.
For detailed Cisco CRS Power Distribution Unit AC power specifications, see the Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide. .
The Cisco CRS 8-slot line card chassis has two fan trays, with four fans each, that cool the chassis card cages. Cool air flows in at the bottom front of the chassis and flows through the chassis card cages and through the fans in the fan trays before being exhausted through the bottom rear of the chassis, as shown in the figure below.
In addition, each fixed configuration AC or DC power module at the bottom of the chassis has self-contained fans that pull in cool air from the front of the chassis and exhaust warm air out the rear.
A replaceable air filter is located on the front of the chassis below the PLIM card cage. Each fixed configuration power module also has a replaceable air filter that attaches to the module at the front side of the chassis. How often you should replace the air filters 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 filters to see if they need to be replaced.
Note | We recommend that you check the air filters once a month. Replace a filter when you notice a significant amount of dust. |
The 8-slot LCC airflow volumes are as follows:
The 8-slot line card chassis dissipates considerable power that generates much heat. In large configurations, additional air cooling is required to maintain correct operating temperatures. The room air must be cooled by external cooling units that are installed as part of the routing system.
>Heat dissipation and external cooling requirements for the 8-slot line card chassis are as follows:
To ensure that the site provides the proper air circulation for the system: