Power Supply in EX3200 Switches

The power supply in EX3200 switches is a hot-removable and hot-insertable field-replaceable unit (FRU) that you can install on the rear panel without powering off the switch or disrupting the switching function. The power supply in EX3200 switches is not redundant.

EX3200 switches use power supplies that provides two DC output voltages: 12 V for system and logic power and 48–51 V (or higher, to compensate for voltage drops along the path from the power supplies to the RJ-45 connector) for PoE ports.

Note: After powering on an the switch, wait for at least 60 seconds before powering it off. After powering off the switch, wait for at least 60 seconds before powering it back on. After the switch has been powered on, it can take up to 60 seconds for status indicators—such as LEDs on the power supply, show chassis command output, and messages on the LCD panel—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds.

This topic describes:

AC Power Supplies

The AC power supply for the switch is available in 320 W, 600 W, and 930 W models (see Figure 1 and Figure 2). The exterior of the 600 W model is identical to that of the 930 W model. The 320 W power supply is flush with the chassis. The 600 W power supply and 930 W power supply extend out of the chassis by 2.25 in. The power cord retainer clips extend out of the power supply by 3 in. The number of ports on which PoE is enabled determines the minimum power requirements of different switch models.

Figure 1: 320 W AC Power Supply

Figure 2: 600 W and 930 W AC Power Supplies

To avoid electrical injury, follow instructions in Installing a Power Supply in an EX3200 Switch and Removing a Power Supply from an EX3200 Switch or Installing a Power Supply in an EX4200 Switch or Removing a Power Supply from an EX4200 Switch carefully.

DC Power Supplies

The DC power supply for the switch is available in a 190 W model, with dual input feeds for power resiliency (see Figure 3).

Note: The DC power supply in the switch does not support Power over Ethernet (PoE); you can use either an external power injector or an AC power supply to supply power to PoE devices that you connect to the switch.

Note: The DC power supply in the switch has four terminals labeled A+, B+, A–, and B– (see Figure 3) 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.

Figure 3: DC Power Supply

To avoid electrical injury, follow instructions in Installing a Power Supply in an EX3200 Switch and Removing a Power Supply from an EX3200 Switch or Installing a Power Supply in an EX4200 Switch or Removing a Power Supply from an EX4200 Switch carefully.

PoE Power Budget and AC Power Supplies

The PoE power budget for a PoE switch model is determined by the capacity of its power supply. For EX3200 switches, the capacity of the power supply provided with a PoE model is sufficient to supply each PoE-capable port with up to 15.4 W in compliance with the IEEE 802.3af PoE standard. Table 1 lists the EX3200 switch PoE models, their power supply ratings, and the associated PoE power budgets.

Starting with Junos OS Release 11.1, EX3200 switches support enhanced PoE, a Juniper Networks extension to the IEEE 302.3af PoE standard. Enhanced PoE permits up to 18.6 W per PoE port. Because the power supply provided with a switch is designed to supply a maximum of 15.4 W per PoE port, if you connect a powered device that draws more than 15.4 W, the PoE power budget might not be sufficient to supply a full 15.4 W to the remaining PoE ports.

Note: Switches upgraded to Junos OS Release 11.1 from a previous release require a separate upgrade of the PoE controller software to enable enhanced PoE support.