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Connect the JCS 1200 DC Platform to DC Power
The JCS 1200 DC power inputs are
configured for DC isolated return (DC-I). The DC return terminal or
conductor is not connected to the equipment frame or the grounding
means of the equipment.
The JCS 1200 DC platform has four DC power terminal connectors
(see Figure 6).
Each DC terminal has four M6 (0.25-inch) studs, one for –48
V DC, one for RETURN (RTN), and two for connecting the grounding
Figure 6: DC Power
To connect the JCS 1200 DC platform to DC
- Ensure that the voltage across the DC power source
cable leads is 0 V and that there is no chance that the cable leads
might become active during installation.
- Verify that a licensed electrician has attached
the cable lugs to the power cables.
- Switch both circuit breakers on the power supply
faceplate to the off position (O).
- Attach an electrostatic discharge (ESD) grounding strap to your bare
wrist and connect the strap to one of the ESD points on the chassis. For more information about ESD, see the JCS 1200 Platform Hardware Guide.
- Remove the terminal cover for each terminal:
- Remove the two Phillips-head screws that attach the terminal
cover to the DC power box.
- Pull the terminal cover away from the JCS 1200 platform.
- Attach the lugs on the DC source power cables to
the terminal studs, making sure the cables are not touching or in
the way of any JCS 1200 platform components. When connecting a cable
lug to each stud, install a flat washer on the stud, install the cable
lug, install a flat washer, install a split washer, and then install
a nut (see Figure 7).
Torque the wiring terminal nuts to 13.3 lb-in. (1.5 Nm).
Figure 7: Attach the Cable
Lugs to the DC Power Terminal Connectors
- Attach the positive (+) DC source power cable lugs to
the RTN (return) terminals.
- Attach the negative (–) DC source power cable lugs
to the –48V (input) terminals.
- Attach the safety ground wire to the other two terminals
- Verify that the power and ground cabling are correct.
- Replace the terminal cover for each terminal:
- Orient the terminal cover so that the terminal cover fits
over the DC power terminals and the screw holes on the terminal cover
are aligned with the screw holes on the DC power box.
- Install two Phillips-head screws that attach the terminal
cover to the DC power box.
Only trained service personnel other than Juniper Networks
service technicians are authorized to make the connections to and
disconnections from the –48 volt DC power source. Juniper Networks
service technicians are not certified or authorized to install or
remove the –48 volt power cable. The customer is responsible
for ensuring that only trained service personnel install or remove
the –48 volt power cable.
The following guidelines are provided for connecting a 60-A JCS 1200 platform
to a –48 V DC power source:
- The power source must have a minimum of 80 A overcurrent
protection. See article 240, paragraph 3, table 310-16 of the National
Electric Code for more information about electrical wiring requirements.
- The overcurrent protective device or circuit breaker must
be accessible to service personnel to prevent the power from being
turned on by someone other than a technician servicing the JCS 1200 platform.
- The JCS 1200 platform requires a DC wire rating of 4
AWG (circular mil area of 33100-52600) and of 90° C.
The actual wire gauge and ring terminal are determined
by the current draw and the length of wire run or as specified by
the customer premises guidelines.
- Flexible DC wiring is recommended to allow for minimum
- The supply wiring to the power connectors must be terminated
in UL-recognized insulated ring terminals, sized for an M6 stud, 4
AWG wire (circular mil area of 33100-52600), and a wire insulation
diameter of 12.8 to 13.1 mm. An example of this type of ring terminal
is Amp Plasti-Grip type 520431 using Tyco Electronics Hydraulic Crimping
Tool part number 14907491.
- For NEBS compliance, the grounding cable must use copper
conductors with a size minimum of 6 AWG (circular mil area of 2080033100)
and must be terminated in a UL-recognized two-hole lug sized for an
M6 stud. An example of this type of two-hole lug is the Thomas and
Betts part number 54205 using the Thomas and Betts crimping tool model
- Torque the wiring-terminal nuts to 13.3 lb-in. (1.5 Nm).
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