Router Power Requirements

Table 25 lists the power requirements for various hardware components when the router is operating under typical voltage conditions. For PIC power requirements, see the M20 PIC Guide.

Table 25: Component Power Requirements

You can use the information in Table 25 and the M20 PIC Guide to calculate power consumption for various hardware configurations, input current from a different source voltage, and thermal output, as shown in the following examples. (These examples use a generalized value for PICs of 0.625 A @ 48 V each.)

• Power consumption for minimum configuration:

  Base system  +  1 FPC  +  1 SSB  +  1 Routing Engine  +  4 fans  +  4 PICs =

  4 A  +  0.03 A  +  1.05 A   +  0.2 A  +  4(0.625 A)   +  4(0.625 A) =

  4 A  +  0.03 A  +  1.05 A  +  0.2 A   +  2.5 A  +  2.5 A = 10.3 A @ 48 V = 495 W DC

• Power consumption for maximum configuration:

  Base system  +  4 FPCs  +  2 SSBs  +  2 Routing Engines  +  4 fans  +  16 PICs =

  4 A   +  4(0.03 A)  +  2(1.05 A)  +  2(0.2 A)  +  4(0.625 A)  +  16(0.625 A)    =

  4 A  +  0.12 A  +  2.1 A  +  0.4 A  +  2.5 A  +  10 A = 19.1 A @ 48 V = 917 W DC

• Input current from a DC source other than 48 V (based on maximum configuration; applies to DC power supply only):

  (54 VDC input)  x  (input current X) = (48 VDC input)  x  (input current Y)

  54  x  X = 48  x  19.1 A

  X = 48  x  19.1 A/54 = 17.0 A

• System thermal output for maximally configured AC-powered router:

  Watts DC/85% AC PEM efficiency/0.293 = BTU/hr

  917/0.85/0.293 = 3682 BTU/hr

• System thermal output for maximally configured DC-powered router:

  Watts DC/0.293 = BTU/hr

  917/0.293 = 3130 BTU/hr

  Note: If you plan to operate a maximally configured DC-powered router, we recommend that you provision at least 24 A @ 48 VDC and use a facility circuit breaker rated for 30 A minimum. Doing so enables you to operate the router in any configuration without upgrading the power infrastructure, and allows the router to function at full capacity using one power supply. If you plan to operate a DC-powered router at less than the maximum configuration and do not provision a 30 A circuit breaker, we recommend that you provision a circuit breaker rated for at least 125% of the continuous current that the system draws at 48 V.