3750x PoE Power Supply Question

[Patrick McHenry]

Looking at the specs for the 3750 power supply - is the WS-C3750X-48P-S model with the 715W power supply referring to the amount for both power supplies per switch or just one power supply per switch? Meaning, is the 715 a accumulative number or, just the watts of one power supply. I would like to purchase a 3750x PoE switch with redundant power supplies. If this model is not the correct one, could you please give me the model that offers 48 port PoE with redundant power supplies?

Thanks, Pat

[smehrnia · Accepted solution]

Hi Pat,

the spec u read about 3750X is with One default AC power supply, 715W (435W PoE power). you could order a backup power supply and install it anytime for redundancy.

EDIT:

available power supply Part #: C3KX-PWR-715WAC  (435W PoE power)   AND   C3KX-PWR-1100WAC  (800W PoE power)

Hope it Helps,

Soroush.

[Patrick McHenry]

Thanks for the response. So that model  provides one power supply but, I have the option to add another later.

If I add another, should I base my UPS backup one 1500W?

Thanks, Pat.

[Reza Sharifi · Accepted solution]

Pat,

Since you device is POE, if you need redundancy you second power supply should be 715w.  Also, these power supplies don't work in combined mode, so you have one working and the other one is on stand-by.  So, your UPS can be based on one PSU (715w).  Just don't forget to connect the second PSU to your UPS.

HTH

[smehrnia]

Anytime!

for UPS power calculation you must consider the amount of power that the PoE devices receive from the switch.

C3750X has the capability to feed 30W PoE power per port and in certain configurations you can achieve that, and that'd need a 2200W at its Max.

PS: i edited my previous post with different PS choices u have, in case u need 30W PoE for 48 ports, u r gonna need two C3KX-PWR-1100WAC or a combination of 1100W and 715W Minimum.

Hope it Helps,

Soroush.

[Patrick McHenry]

Or is only one PS active at a time and basing my backup on 750 would be good?

Thanks, Pat.

[smehrnia]

Take a look at Table 8 :

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/data_sheet_c78-584733.html

HTH,

Soroush.