Need to understand power use for 1238P at different Loads

[fluidnets]

Hi,

I have a 1238P latest GEN Switch with 48 POE Phs connected to it. Ea PH uses about 6W. I see the 1238P is rated @ 500 Watts and 4.9Amps. Would it b safe to say that in the config here, the WATTs being used to determine a UPS run time is 6W x 48 PHs = 288 watts OR is it closer to the 500Watts due to some other factors?

Same Q for 1534P - I have a 1534P latest GEN Switch with 24 POE Phs connected to it. Ea PH uses about 6W. I see the 1238P is rated @ 500 Watts and 4.9Amps. Would it b safe to say that in the config here, the WATTs being used to determine a UPS run time is 6W x 24 PHs = 144 watts OR is it closer to the 500Watts due to some other factors?

Thanks

Jim

[jayh · Accepted solution]

Nameplate power ratings on gear are typically a worst-case maximum.  If all PoE devices are at max and the fans are at max, high CPU, etc. you might come close to the 500 watts.  A clamp-on ammeter with a sense loop (multiply amps times 120 for US) or inline wattmeter such as a Kill-A-Watt will tell you the consumption right now but not the maximum under different conditions.

Nameplate ratings on UPSes are often an optimistic marketer's best hope.

Get a UPS that is capable of 500 watts for safety, your switch should never pull more than that.  Note that run time on the UPS is a function of battery capacity and load, not maximum rating.

[Anonymous]

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Thanks,

Noor