Juniper EX Switch PSU Compatibility and Wattage Upgrade Question

[wesleycolton238]

Hi,

I’m fairly new to enterprise networking hardware, and I’ve run into a compatibility issue with Power Supplies Juniper switches use. I’m hoping someone here can help clarify a few things.

• Can I use a different wattage PSU within the same Juniper switch series?

For example, I have a Juniper EX switch that originally shipped with a lower wattage AC PSU. I recently purchased a higher wattage module that appears physically identical and slides in perfectly. However, I’m unsure whether Junos will fully support it or if there are model specific restrictions tied to firmware or hardware revision.

• Are Juniper PSUs cross compatible between EX or QFX models?

Some units look very similar, but documentation lists them separately. Is compatibility strictly enforced, or mainly related to airflow direction and power budgeting?

[rproffitt]

Given the cost of the gear in question I would never use a PSU that isn't listed for use with the Juniper switch in question.

But hey, your hardware to smoke!

[Annie warner]

With Juniper, PSU compatibility can depend on the exact switch SKU, PSU part number, wattage and airflow direction. For example Juniper’s QFX documentation explicitly lists cases where different wattages or airflow configurations cannot be mixed and Junos can raise an alarm when an unsupported PSU is installed.
I would also be careful about assuming that an EX-series PSU will work in a QFX switch or vice versa. Some modules may look almost identical mechanically while having different electrical or firmware requirements. Juniper’s documentation generally specifies the supported PSU part numbers for each particular chassis rather than treating the modules as universally interchangeable.
So before installing the higher-wattage PSU, I would check the exact EX model/SKU and the part number printed on both the original and replacement PSUs. The airflow direction is important too, since the PSU and fan airflow need to match.
If you post the exact EX model (for example, EX3400-48P) and the part numbers of both PSUs, someone should be able to confirm whether that particular combination is supported.