Dc Power Electrical Safety Guidelines - Juniper MX240 Hardware Manual

WARNING: The router is pluggable type A equipment installed in a restricted-access
location. It has a separate protective earthing terminal (sized for UNC 1/4-20 ground
lugs) provided on the chassis in addition to the grounding pin of the power supply
cord. This separate protective earthing terminal must be permanently connected to
earth.
The cores in the mains lead are colored in accordance with the following code:
Green and yellow-Earth
Blue-Neutral
Brown-Live
DC Power Electrical Safety Guidelines and Warnings
When working with DC-powered equipment, observe the following guidelines and
warnings:
DC Power Electrical Safety Guidelines on page 149
Copper Conductors Warning on page 150
DC Power Disconnection Warning on page 151
DC Power Grounding Requirements and Warning on page 152
DC Power Wiring Sequence Warning on page 153
DC Power Wiring Terminations Warning on page 154

DC Power Electrical Safety Guidelines

The following electrical safety guidelines apply to a DC-powered router:
A DC-powered router is equipped with a DC terminal block that is rated for the
power requirements of a maximally configured router. To supply sufficient power,
terminate the DC input wiring on a facility DC source capable of supplying at
least 31 A @ -48 VDC per input for each power supply.
Incorporate an easily accessible disconnect device into the facility wiring. We
recommend that the 48 VDC facility DC source should be equipped with a circuit
breaker rated at 40 A (-48 VDC) minimum, or as required by local code. In the
United States and Canada, the 48 VDC facility should be equipped with a circuit
breaker rated a minimum of 125% of the power provisioned for the input in
Appendix A: Safety and Regulatory Compliance Information
Safety Guidelines and Warnings
149