Juniper EX4200 Hardware Manual page 138

CAUTION:
attach a cable lug to the grounding and power cables that you supply. A cable with
an incorrectly attached lug can damage the switch (for example, by causing a short
circuit).
To meet safety and electromagnetic interference (EMI) requirements and to ensure
proper operation, you must connect EX4200 switches to earth ground before you
connect them to power. For installations that require a separate grounding conductor
to the chassis, use the protective earthing terminal on the switch chassis to connect
to the earth ground. For instructions on connecting earth ground, see
Ground to an EX Series Switch" on page
Install the power supply in the chassis. For instructions on installing a power supply in an EX4200 switch,
see "Installing a Power Supply in an EX4200 Switch" on page
Ensure that you have the following parts and tools available:
DC power source cables (12–14 AWG) with ring lug (Molex 190700067 or equivalent) (not provided)
Phillips (+) screwdriver, number 2
To connect DC power to the switch:
1. Ensure that the power supplies are fully inserted in the chassis and the screws on their faceplates are
tightened.
2. Ensure that the input circuit breaker is open so that the voltage across the DC power source cable
leads is 0 V and that the cable leads will not become active while you are connecting DC power.
NOTE: The DC power supply in the switch has four terminals labeled A+, B+, A–, and B–
(see Figure 43 on page
negative (–). The DC power supplies are shipped with jumpers from A+ input to B+ input tied
together and jumpers from A– input to B– input tied together.
NOTE: The A+ and B+ terminals are referred to as +RTN and A– and B– terminals are referred
to as –48 V in "DC Power Wiring Sequence Warning" on page 307
Safety Guidelines" on page
Before you connect power to the switch, a licensed electrician must
137) for connecting DC power source cables labeled positive (+) and
302.
127.
197.
and "DC Power Electrical
"Connect Earth
138