Dc Power Circuit Breaker Requirements - Juniper MX204 Hardware Manual

Calculating System Thermal Output
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DC Power Circuit Breaker Requirements for the MX204 Router
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Documentation
Copyright © 2018, Juniper Networks, Inc.
Table 29: MX204 Router DC Router Power Requirements at Maximum Temperature (55°
C)
Chassis Configuration
Fully configured chassis
running at high activity
After you have calculated the power consumption for your configuration, you can use
that information to determine the system thermal output (BTUs per hour). To do so,
multiply the power consumption in watts by 3.41.
For example, in Table 28 on page 50
configured chassis running at high activity at 25° C typical temperature to be 240 W.
Using that information we can calculate the system thermal output for the configuration:
Power consumption in watts * 3.41 = system thermal output in BTU/hr
240 W * 3.41 = 818.4 BTU/hr
MX204 Power System Description on page 21
Replacing an MX204 DC Power Supply on page 99
DC Power Circuit Breaker Requirements for the MX204 Router on page 51
DC Power Source Cabling for MX204 Router on page 52
DC Power Cable Specifications for MX204 Router on page 53
General Safety Guidelines and Warnings on page 133
General Electrical Safety Guidelines and Warnings on page 155
Prevention of Electrostatic Discharge Damage on page 156
Each DC power supply has a single DC input (–48 VDC and return) that requires a
dedicated circuit breaker. We recommend that you use a dedicated customer-site circuit
breaker rated for 25 A (–48 VDC) minimum, or as required by local code. Doing so enables
you to operate the router in any configuration without upgrading the power infrastructure.
If you plan to operate a DC-powered router at less than the maximum configuration and
do not provision a 25 A (–48 VDC) circuit breaker, we recommend that you provision a
dedicated customer-site circuit breaker for each DC power supply rated for at least 125
percent of the continuous current that the system draws at –48 VDC.
MX204 Power System Description on page 21
Replacing an MX204 DC Power Supply on page 99
Power Consumption for a DC-Powered MX204 Router on page 50
Chapter 9: DC Power Requirements, Specifications, and Guidelines
Power Requirement at 55° C
(Watts)
280 W
we calculated the power consumption for a fully
Power Requirement (Watts)
with 90% Efficiency
311 W
51