Connecting the EX3200 to Power
Connect Earth Ground to an EX Series Switch
To ensure proper operation and to meet safety and electromagnetic interference (EMI) requirements, you must connect an EX Series switch to earth ground before you connect power to the switch. You must use the protective earthing terminal on the switch chassis to connect the switch to earth ground (see Figure 2).
You must install the EX Series switch in a restricted–access location and ensure that the chassis is always properly grounded. EX Series switches have a two–hole protective grounding terminal provided on the chassis. See Table 1 for the location of the earthing terminals on various EX Series switches. We recommend that you use the protective grounding terminal as the preferred method for grounding the chassis regardless of the power supply configuration. However, if additional grounding methods are available, you can also use those methods. For example, you can use the grounding wire in the power cord of an AC power supply or use the grounding terminal or lug on a DC power supply. This system was tested to meet or exceed all applicable EMC regulatory requirements with the two-hole protective grounding terminal connected correctly.
Ensure that a licensed electrician has attached an appropriate grounding lug to the grounding cable you supply. Using a grounding cable with an incorrectly attached lug can damage the switch.
Parts and Tools Required for Connecting an EX Series Switch to Earth Ground
Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch
Parts and Tools Required for Connecting an EX Series Switch to Earth Ground
Before you begin connecting an EX Series switch to earth ground, ensure you have the parts and tools required for your switch.
Table 1 lists the earthing terminal location, grounding cable and lug specifications, and parts needed for connecting an EX Series switch to earth ground.
Table 1: Parts Required for Connecting an EX Series Switch to Earth Ground
Switch | Earthing Terminal Location | Grounding Cable Requirements | Grounding Lug Specifications | Screws and Washers | Additional Information |
---|---|---|---|---|---|
EX2200 | Rear panel of the chassis | 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCC10-14BWL or equivalent— |
| |
EX2300-C | Rear panel of the chassis | 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCC10-14AW-L or equivalent— |
| |
EX2300 | Rear panel of the chassis |
|
|
| |
EX3200, EX3300, and EX3400 | Rear panel of the chassis | 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCC10-14BWL or equivalent— |
| For EX3200 Switches See Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch. |
EX4200, EX4500, and EX4550 | Left side of the chassis | 14 AWG (2 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCC10-14BWL or equivalent— |
| See Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch. |
EX6210 | Rear panel of the chassis (on lower left side) | The grounding cable must be the same gauge as the power feed cables and as permitted by the local code. | Panduit LCD2-14A-Q or equivalent |
| |
EX8208 | Left side of the chassis | 6 AWG (13.3 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCD2-14A-Q or equivalent |
| |
EX8216 | Two earthing terminals:
Note: You must use only one of the two protective earthing terminals. | 2 AWG (33.6 mm²), minimum 90° C wire, or as permitted by the local code | Panduit LCD2-14A-Q or equivalent |
| |
EX9204, EX9208, and EX9214 | Rear panel of the chassis | One 6 AWG (13.3 mm²), minimum 90° C wire, or one that complies with the local code | Thomas& Betts LCN6-14 or equivalent— |
| See Grounding Cable and Lug Specifications for EX9200 Switches. |
EX9251 | Rear panel of the chassis | 12 AWG (2.5 mm²), minimum 90° C wire,
or one that complies with the local code— | Panduit LCD10-10A-L or equivalent— | Two 10-32 screws— | See Grounding Cable and Lug Specifications for EX9200 Switches. |
EX9253 | Right side of the chassis | 14-10 AWG (2-5.3 mm²), minimum 90° C wire,
or one that complies with the local code— | Panduit LCD10-14B-L or equivalent— | Two M5 Pan Head screws— |
Tools required for connecting an EX Series switch to earth ground:
An electrostatic discharge grounding strap (provided)
A Phillips (+) number 2 screwdriver to tighten the screws.
An AC–powered EX Series switch gains additional grounding when you plug the power supply in the switch into a grounded AC power outlet by using an AC power cord appropriate for your geographical location.
Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch
Table 2 lists the special instructions that you might need to follow before connecting earth ground to a switch.
Table 2: Special Instructions to Follow Before Connecting Earth Ground to an EX Series Switch
Switch | Special Instructions | ||||
---|---|---|---|---|---|
EX3200 and EX4200 | Some early variants of EX3200 and EX4200 switches for which the Juniper Networks model number on the label next to the protective earthing terminal is from 750-021xxx through 750-030xxx require 10-24x.25 in. screws. | ||||
EX4200, EX4500, and EX4550 | If you plan to mount your switch on four posts of a rack or cabinet, mount your switch in the rack or cabinet before attaching the grounding lug to the switch. Note: The protective earthing terminal on switches mounted on four posts of a rack is accessible through the slot on the left rear bracket only if the rack is 27.5 in. (69.85 cm) through 30.5 in. (77.47 cm) deep for a switch mounted flush with the rack front and 29.5 in. (74.93 cm) through 32.5 in. (82.55 cm) deep for a switch mounted 2 in. (5.08 cm) recessed from the rack front. See Figure 1. ![]()
Note: The brackets must be attached to the chassis before the grounding lug is attached. (The brackets are shown pulled away from the chassis so that the protective earthing terminal is seen.) |
Connecting Earth Ground to an EX Series Switch
To connect earth ground to an EX Series switch:
- Verify that a licensed electrician has attached the cable lug to the grounding cable.
- Connect one end of the grounding cable to a proper earth ground, such as the rack in which the switch is mounted.
- Attach an ESD grounding strap to your bare wrist, and connect the strap to the ESD grounding point on the switch.
- Place the grounding lug attached to the grounding cable
over the protective earthing terminal. See Figure 2.
Figure 2: Connecting a Grounding Cable to an EX Series Switch - Secure the grounding lug to the protective earthing terminal with the washers and screws.
- Dress the grounding cable and ensure that it does not touch or block access to other switch components and that it does not drape where people could trip over it.
Connecting AC Power to an EX3200 Switch
The power supply in an EX3200 switch is a field-replaceable unit (FRU).
Before you begin connecting AC power to an EX3200 switch:
Ensure that you have connected the device chassis to earth ground, if required by your site guidelines or installation. A ground connection to the protective earthing terminal is not required for an AC-powered switch. The AC power cords provide adequate grounding when you connect the power supply in the switch to a grounded AC power outlet by using the AC power cord appropriate for your geographical location (see AC Power Cord Specifications for EX3200 Switches).
Caution For installations that require a separate grounding conductor to the chassis, have a licensed electrician complete this connection before you connect the switch to power. For instructions on connecting earth ground, see Connect Earth Ground to an EX Series Switch.
Install the power supply in the chassis. For instructions on installing a power supply in an EX3200 switch, see Installing a Power Supply in an EX3200 Switch.
The power supply must be connected to a dedicated power source outlet.
Ensure that you have the following parts and tools available:
A power cord appropriate for your geographical location
To connect AC power to the switch:
- Ensure that the power supplies are fully inserted in the chassis and the screws on their faceplates are tightened.
- Squeeze the two sides of the power cord retainer clip and insert the L-shaped ends of the wire clip into the holes in the bracket on each side of the AC power cord inlet on the AC power supply faceplate (see Figure 3).
- Locate the power cord or cords shipped with the switch;
the cords have plugs appropriate for your geographical location.
Warning Ensure that the power cord does not block access to switch components or drape where people can trip on it.
- Insert the coupler end of the power cord into the AC power cord inlet on the AC power supply faceplate.
- Push the cord into the slot in the adjustment nut of the power cord retainer. Turn the nut until it is tight against the base of the coupler and the slot in the nut is turned 90° from the top of the switch (see Figure 4).
- If the AC power source outlet has a power switch, set it to the OFF (0) position.
- Insert the power cord plug into an AC power source outlet.
- If the AC power source outlet has a power switch, set it to the ON (|) position.
- Verify that the AC OK LED on the power supply
is lit and is on steadily.
Note When you connect power to the switch, the Alarm (ALM) LED lights red. This behavior is normal. Plugging an active Ethernet cable into the management (MGMT) port on the switch completes the network link and turns off the ALM LED. (See Connect a Device to a Network for Out-of-Band Management.)
Connecting the switch to a dedicated management console instead of a network does not affect the ALM LED. The LED remains red until the switch is connected to a network.


See also
Connecting DC Power to an EX3200 Switch
The power supply in an EX3200 switch is a field-replaceable unit (FRU).

DC-powered EX3200 switches are intended for installation only in a restricted access location.
Before you begin connecting DC power to an EX3200 switch:
Ensure that you have connected the switch chassis to earth ground.
Caution Before you connect power to the switch, a licensed electrician must 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 EX3200 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 Connect Earth Ground to an EX Series Switch.
Install the power supply in the chassis. For instructions on installing a power supply in an EX3200 switch, see Installing a Power Supply in an EX3200 Switch.
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:
- Ensure that the power supplies are fully inserted in the chassis and the screws on their faceplates are tightened.
- 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 5) for connecting DC power source cables labeled positive (+) and 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 and DC Power Electrical Safety Guidelines.
- Remove the screw securing the terminal block cover using
the screwdriver and remove the terminal block cover (see Figure 6).
Save the screw.
Figure 6: Removing the Terminal Block Cover from a DC Power Supply - Remove the screws on the terminals using the screwdriver.
Save the screws.
Warning Ensure that the power cables do not block access to switch components or drape where people can trip on them.
Note To supply sufficient power, terminate the DC input wiring on a facility DC source that is capable of supplying a minimum of 8 A at –48 VDC.
- Connect the power supplies to the power sources. Secure
power source cables to the power supplies by screwing the ring lugs
attached to the cables to the appropriate terminals by using the screw
from the terminals (see Figure 7).
To connect a power supply to a power source:
- Leave the jumpers on the power supply terminals in place.
- Secure the ring lug of the positive (+) DC power source cable to the A+ or B+ terminal on the DC power supply.
- Secure the ring lug of the negative (–) DC power source cable to the A– or B– terminal on the DC power supply.
- Tighten the screws on the power supply terminals until snug using the screwdriver. Do not overtighten—apply between 8 lb-in. (0.9 Nm) and 9 lb-in. (1.02 Nm) of torque to the screws.
If you have a second installed power supply, connect it in the same way you did the first.
To connect one power supply to two power sources:
- Remove the jumpers on the power supply terminal block.
- Secure the ring lug of the positive (+) DC power source cable from the first DC power source to the A+ terminal on the first DC power supply.
- Secure the ring lug of the negative (–) DC power source cable from the first DC power source to the A– terminal on the first DC power supply.
- Secure the ring lug of the positive (+) DC power source cable from the second DC power source to the A+ terminal on the second DC power supply.
- Secure the ring lug of the negative (–) DC power source cable from the second DC power source to the A– terminal on the second DC power supply.
- Tighten the screws on the power supply terminals on both the power supplies until snug using the screwdriver. Do not overtighten—apply between 8 lb-in. (0.9 Nm) and 9 lb-in. (1.02 Nm) of torque to the screws.
Figure 7: Securing Ring Lugs to the Terminals on the DC Power Supply - Replace the terminal block cover and secure it using the screw. Use the screwdriver to tighten the screw.
- Close the input circuit breaker.
- Verify that the LEDs on the power supply are lit green and are on steadily.