• Related Topics
• AC Power Specifications for EX8200 Switches
• AC Power Supply LEDs in an EX8200 Switch
• Calculating Power Requirements for an EX8208 Switch
• Calculating Power Requirements for an EX8216 Switch
• Installing an AC Power Supply in an EX8200 Switch
• Removing an AC Power Supply from an EX8200 Switch

AC Power Supply in an EX8200 Switch

AC Power Supply Description

The AC power supplies in EX8200 switches are hot-insertable and hot-removable field-replaceable units (FRUs).

You can install up to six AC power supplies in an EX8200 switch. Power supplies are installed at the bottom of the chassis in slots PSU 0 through PSU 5 (left to right). All power supplies are accessible from the front of the chassis.

Warning: The switch is pluggable type A equipment installed in a restricted-access location. It has a separate protective earthing terminal 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 ground.

Note: All base configuration EX8200 switches are shipped with two power supplies. Cover panels are installed over the remaining four power supply slots. Additional power supplies can be added to base configuration switches as necessary. For details about different switch configurations, see EX8208 Switch Configurations or EX8216 Switch Configurations.

Each AC power supply weighs approximately 7 lb (3.2 kg) and has an independent 16 A rated AC inlet on its front. Each inlet requires a dedicated AC power feed. Each AC power supply has an Enable switch, a fan, and three LEDs on the faceplate that indicate the status of the power supply. See Figure 1.

Each AC power supply comes with a power retainer that holds the power cord in place. See Figure 2. The power retainer has a clip and an adjustment nut. The L-shaped ends of the clip hook into the bracket holes on each side of the AC appliance inlet on the faceplate. The adjustment nut holds the power cord in the correct position. For instructions for installing the power retainer, see Connecting AC Power to an EX8200 Switch.

Each power supply connects to the backplane in an EX8208 switch and to the midplane in an EX8216 switch. The backplane and the midplane distribute the output power produced by the power supplies to different switch components. Each AC power supply provides power to all the components in the switch.

Each power supply has its own fan and is cooled by its own internal cooling system. The airflow is from the front of the power supply to the back. Hot air exhausts from the rear of the chassis.

EX8200 switches support both 2000 W AC power supplies and 3000 W AC power supplies.

The 2000 W AC power supply supports both the low-voltage line (100–120 VAC) and the high-voltage line (200–240 VAC) AC power configurations. In both cases, the output is 52 VDC. The output power is 1200 W for low-voltage line input and 2000 W for high-voltage line input.

The 3000 W AC power supply supports only the high-voltage line input (200–240 VAC) AC power configuration. Low-voltage line input is not supported for the 3000 W AC power supplies on the EX8200 switches. The output is 52 VDC. The output power is 3000 W for high-voltage line input.

N+1 Redundancy Configuration of AC Power Supplies

N+1 redundancy configuration is required for normal operation of EX8200 switches. In an N+1 redundancy configuration, if one power supply fails or is removed, the remaining power supplies continue to supply power for the switch without interruption.

Depending on the configuration type of the switch and the input voltage, determine the number of power supplies needed (N) for a switch. Install an additional power supply to meet the required N+1 redundancy configuration. For details about different switch configurations, see EX8208 Switch Configurations or EX8216 Switch Configurations.

The tables in this section list the N+1 power requirements for different EX8200 switch configurations:

• Table 1—Lists the N+1 power requirements of EX8208 switch configurations that use 2000 W AC power supplies.
• Table 2—Lists the N+1 power requirements of EX8208 switch configurations that use 3000 W AC power supplies.
• Table 3—Lists the N+1 power requirements of EX8216 switch configurations that use 2000 W AC power supplies.
• Table 4—Lists the N+1 power requirements of EX8216 switch configurations that use 3000 W AC power supplies.

N+N Redundancy Configuration of AC Power Supplies

You can optionally configure your switch for N+N redundancy, in which N power supplies can be removed or fail and the remaining N power supplies continue to supply power for the switch without interruption. A common application for N+N redundancy is to have a dual power feed for AC power supplies.

How many power supplies you require for N+N redundancy can depend on which Junos OS Release your switch is running:

• Junos OS Release 10.1 or earlier—Consult Table 1, Table 3, or Table 4 to determine the number of power supplies needed (N). Then multiple the N value by two.

  Note: In Junos OS Release 10.1 or earlier, the power management feature manages switches for N+1 redundancy only. This means, for example, that power management raises an alarm if there is insufficient power to maintain N+1 redundancy, but not if there is insufficient power to maintain N+N redundancy.

• Junos OS Release 10.2 or later—Consult Table 5, Table 7, or Table 8 in this section.

Starting with Junos OS Release 10.2, you can configure the power management software to manage the switch power for N+N redundancy. When you configure power management for N+N redundancy, power management lowers the maximum chassis power consumption by lowering the maximum fan speed. It does so to compensate for the extra power that is held in reserve in an N+N configuration than in an N+1 configuration, because of which less power would ordinarily be available to power line cards. By reducing the maximum chassis power consumption, power management allows the switch to power more line cards.

The configuration type of the switch and the input voltage determine the number of power supplies needed (N) for the switch. You must then install additional power supplies to meet the N+N redundancy configuration. For details about different switch configurations, see EX8208 Switch Configurations or EX8216 Switch Configurations.

The tables in this section list the N+N power requirements for different EX8200 switch configurations:

• Table 5—Lists the N+N power requirements of EX8208 switch configurations that use 2000 W AC power supplies.
• Table 6—Lists the N+N power requirements of EX8208 switch configurations that use 3000 W AC power supplies.
• Table 7—Lists the N+N power requirements of EX8216 switch configurations that use 2000 W AC power supplies.
• Table 8—Lists the N+N power requirements of EX8216 switch configurations that use 3000 W AC power supplies.