Description

This article describes the supported Power Supply Units (PSUs) for the Juniper EX4100 switch family and provides guidance for identifying PSU compatibility issues.

A common issue occurs when a PSU from a non-PoE EX4100 model (150W) is installed in a PoE-capable EX4100 model that requires a 920W PSU.

Symptoms

An EX4100 PoE switch may exhibit the following behavior when an unsupported PSU is installed:

 

  • The PSU can be inserted in either power supply slot.
  • The switch does not power on when only the unsupported PSU is installed.
  • The switch powers on normally when a supported PSU is used.
  • Redundancy is not achieved despite the PSU LEDs indicating normal operation.
  • Similar alarms as below may trigger:

root@user> show chassis alarms no-forwarding
1 alarms currently active
Alarm time Class Description
2024-08-13 14:31:02 IST Major FPC 0 PEM 0 is not supported

From the show chassis hardware detail output, it has been noticed that the PEM0 is installed with 600W power module due to which an unsupported alarm is noticed.
 

root@user> show chassis hardware detail no-forwarding

Hardware inventory:
Item             Version  Part number  Serial number     Description
Chassis                                XXXXXXXXXXXX      EX4100-24T
FPC 0            REV 08   650-134067   XXXXXXXXXXXX      EX4100-24T-CHAS
Power Supply 0   REV 04   640-060602   xxxxxxxxxxxx      JPSU-600W-AC-AFO
Power Supply 1   REV 07   640-060603   xxxxxxxxxxx       JPSU-150W-AC-AFO

The Alarm is expected as the EX4100 doesn't support 600W PSUs.

 

Solution

  • The EX4100-24P and EX4100-48P (PoE+ switches) use 920W power supplies.
  • The EX4100-24MP and EX4100-48MP (PoE++ switches) use 920W power supplies.
  • The EX4100-24T, EX4100-48T, and EX4100-48T-AFI (Non-PoE switches) use 150W power supplies.


The supported PSU matrix:

Model/Product SKUAccess Port ConfigurationPoE/PoE+PortsPoE++PortsPoE Budget 1 PSU/2 PSU10GbE Ports25GbE PortsPower Supply RatingCooling
EX4100-24T24-port
10/100/1000BASE-T		00N/A44150 W ACAFO (front-to-back airflow)
EX4100-48T48-port
10/100/1000BASE-T		00N/A44150 W ACAFO (front-to-back airflow)
EX4100-48T-AFI48-port
10/100/1000BASE-T		00N/A44150 W ACAFI (back-to-front airflow)
EX4100-24T-DC24-port
 10/100/1000BASE-T		00N/A44150 W DCAFO (front-to-back airflow)
EX4100-48T-DC48-port
10/100/1000BASE-T		00N/A44150 W DCAFO (front-to-back airflow)
EX4100-24P24-port
 10/100/1000BASE-T		240740 W/1440 W44920 W ACAFO (front-to-back airflow)
EX4100-48P48-port
10/100/1000BASE-T		480740 W/1440 W44920 W ACAFO (front-to-back airflow)
EX4100-24MP8x 100
MB/1GbE/2.5GbE/5GbE/10GbE + 16x 10 MB/100 MB/1GbE		024740W/1620 W124920 W ACAFO (front-to-back airflow)
EX4100-48MP16x 100 MB/1GbE/2.5GbE
+ 32x 10 MB/100 MB/1GbE		048740 W/1620 W44920 W ACAFO (front-to-back airflow)


For further information refer:
https://www.juniper.net/gb/en/products/switches/ex-series/ex4100-line-of-ethernet-switches-datasheet.html
https://www.juniper.net/documentation/us/en/hardware/ex4100/topics/topic-map/ex4100-power-system.html

Modification History

2024-08-23 : Article Created
2026-07-21 : Changes to formatting, appearance and included more data.