Swapping 1100W PSUs for 700

[stonent01]

We have some of the 9300 5Gb switches with the 1100W PSUs in them.  Because of the length they don't fit in some of our older cabinets.  What will happen if we swap the 1100W PSUs with the shorter 700W ones from the 9300-48P switches? Specifically I want to know about the power behavior.  Will it reduce the number of 90W devices that can be used, or will it disable 90W entirely and just issue out 30W PoE?
Secondly if we put the 1100W PSUs in a 48P switch, will it gain any functionality?

I don't actually need 90W at this time but I just want to be aware of what to expect over the lifecycle of the switches.

[Paul Chapman · Accepted solution]

Changing the power supplies changes the overall power budget of the switch, not the output capabilities of an individual port..  Power is provided on a first-come-first-served basis by default. If there is not enough power left to support a device requesting power, then it will get a "power denied" response.

You can see the available power with `show power inline` (example below).

#show power inline

Module Available  Used    Remaining
       (Watts)   (Watts)  (Watts) 
------ --------- -------- ---------
1      1745.0    301.9    1443.1

NOTE: Dual-voltage power supplies produce different output Watts depending on input voltage, so the `show power inline` command should be your guide for usage planning.

PSC

[Reza Sharifi · Accepted solution]

The 715 PSU should work fine with POE+. If you want to know how much you power are currently using, issue the command

sh power inline

This command should show how much power you are using and what is total budget for POE.

example:

Module Available Used Remaining
(Watts) (Watts) (Watts)
------ --------- -------- ---------
1 1440.0 138.6 1301.4

HTH