Observe the following guidelines for DC-powered shelves. In addition, be sure to review the requirements described in the Bonding and Grounding Guidelines section.

• A DC-powered chassis requires up to a maximum of 9,500 watts of DC input power when the chassis is fully loaded.
• Two separate and independent power sources are required for N+N redundancy, each providing nominal –48/-60 VDC, 60 A service (four inputs per shelf). The system will operate with power to only one shelf but will not have N+N redundancy.
• All power connection wiring must conform to the rules and regulations in the National Electrical Code (NEC) and any local codes. In addition, make sure that the wiring conforms to any internal requirements at the installation site.
• Each DC power source must comply with the safety extra-low voltage (SELV) requirements in UL 60950-1, CSA-C22.2 No. 60950-1, EN60950-1, AS/NZS 60950, and IEC60950-1.
• A DC-powered system should be installed in a restricted access area in accordance with the National Electric Code, ANSI/NFPA 70.
• All components in the area where DC input power is accessible must be properly insulated.
• If it is not possible to rely on the identification of the earthed conductor in the DC mains supply, whereby the equipment is not provided with a two-pole disconnect device, then a two-pole disconnect device is to be provided external to the equipment.

The following table lists the DC input current and voltage specifications.

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:

• Each power shelf requires up to four pairs of distribution cables, DC (–48) and RTN (+).
• Paired battery and RTN cables should have the same cable lengths and should run together for equalization.
• Use the appropriate wire gauge for –48/-60 VDC, 60 A service. We recommend that you use a commensurately rated, high-strand-count copper cable. This cable is not available from Cisco Systems; it is available from any commercial vendor.

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.

• Each DC input power cable is terminated at the power shelf by a cable lug. The power supply terminal block lug opening width is 0.63 inch (1.60 cm). The cable lug must be dual hole and able to fit over M6 terminal studs at 0.63-inch (1.60 cm) centers. We recommend that you use an appropriately sized 180-degree angle (straight) industry standard dual-hole, standard barrel compression lug, as shown in 180 Degree (Straight) DC Input Power Cable Lug, or an appropriately sized 45-degree angle industry standard 2-hole, standard barrel compression lug, as shown in 45 Degree DC Input Power Cable Lug.

Figure 3. 180 Degree (Straight) DC Input Power Cable Lug

Figure 4. 45 Degree DC Input Power Cable Lug

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 DC power shelf terminal studs.

Figure 5. DC Power Shelf Power Cable Connections

Note	In the DC power system, the power wire connectors have a torque value of 20 in-lb (2.26 N-m).

In addition to the requirements in the Bonding and Grounding Guidelines section, AC input power requirements are as follows:

• An AC-powered chassis requires up to a maximum of 9,800 watts of AC input power when the chassis is fully loaded.
• Two separate and independent AC power sources are required for N+N redundancy, one for each power shelf. Each power shelf should be connected to a different power source to provide 2N power redundancy in case a power source fails. The system will operate with power to only one shelf but will not have N+N redundancy.
• Each AC power source must provide single-phase AC power, and have its own circuit breaker.
• The AC power receptacles used to plug in the chassis must be the grounding type. The grounding conductors that connect to the receptacles should connect to protective earth ground at the service equipment.
• AC single-phase input:
  • Single-phase, 200 to 240 VAC nominal, 50 to 60 Hz, 16 A International and 20 A North America.
  • Each AC power shelf contains three IEC-320-C22 receptacles which can accept up to three IEC-320-C21 connector female plugs.
• If you have 3-phase AC Delta or AC Wye at your equipment, a Cisco CRS 3-phase AC PDU will be required to convert 3-phase AC input power to single-phase AC input power for the power shelf. For further information, refer to Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide .

Note	If you have a Cisco CRS 3-phase AC PDU installed, three AC PMs are required to be installed in each AC power shelf to maintain a balanced 3-phase power load.

For detailed AC power specifications, see the Line Card Chassis Specifications section.

The AC power shelf is shipped with AC power cords when the AC PDU is not ordered. Each AC power shelf accepts up to three power cords. Each AC power cord is 4.25 m in length and different plug types (pre-attached) are available, depending on the locale. AC power cords are available for the following locales:

• North America
• Europe
• United Kingdom
• Italy
• Australia

The following table lists the single-phase AC-input cord power options and Cisco product numbers for the Cisco CRS 8-Slot Line Card Chassis Enhanced router with AC power shelves installed. The table also references power cord illustrations.

Figure 6. North America—AC-Input Power Cord

Figure 7. Europe—AC-Input Power Cord

Figure 8. United Kingdom— AC-Input Power Cord

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.

Figure 9. Italy—AC-Input Power Cord

Figure 10. Australia—AC-Input Power Cord

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 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.

There are two versions of the Cisco CRS 3-Phase AC PDU available for the Cisco CRS8-Slot Line Card Chassis Enhanced router:

• CRS-8-PDU-Delta—Redundant 3-phase to single-phase Delta PDU for Cisco CRS 8-Slot Line Card Chassis Enhanced router, 2 input/6 output
• CRS-8-PDU-Wye—Redundant 3-phase to single-phase Wye PDU for Cisco CRS 8-Slot Line Card Chassis Enhanced router, 2 input/6 output

In addition to the requirements in the General Power and Grounding Requirements section, AC input power requirements are as follows:

• Two separate and independent AC power sources are required, one for each PDU. Each PDU should be connected to a different power source to provide 2N power redundancy in case a power source fails.
• Each AC power source must provide 3-phase VAC power, and have its own circuit breaker.
• AC Delta input:
  • 3-phase, 200 to 240 VAC (phase-to-phase), 50 to 60 Hz.
  • Input current: 27.7 A.
  • Each PDU has one Delta input power cord with a 4-pin IEC 60309 plug (3 wire + protective earthing [3W+PE]). The power cord is rated for 250 VAC, 60 A, and plugs into a similarly rated IEC 60309 receptacle.
  • Each PDU has three single phase output cords preattached, each with a 90 degree IEC-320-C21 plug that plugs into a IEC-320-C22 inlet on the rear of the AC power shelf.
• AC Wye input:
  • 3-phase, 200 to 240 VAC (phase-to-neutral), 50 to 60 Hz.
  • Input current: 16 A (International) or 20 A (North America). The PDU is rated for 16-amp service.
  • Each PDU has one Wye power cord with a 5-pin IEC 60309 plug (3 wire + neutral + protective earthing conductor (ground wire) [3W+N+PE]). The cord is rated for 415 VAC, 16 A, and plugs into a similarly rated IEC 60309 receptacle.
• Grounding-type AC power outlet is required. The PDUs are shipped with AC power cords that have a grounding-type plug. As a safety feature, the plugs fit only a grounding-type AC power outlet.

Figure 11. AC Delta Power Cord Plug

Figure 12. AC Wye Power Cord Plug

For detailed Cisco CRS Power Distribution Unit AC power specifications, see the Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide.