David Hornstein Sat, 10/10/2009 - 01:05
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Hi Lukasz,

I also  note that this information is missing from the datasheet, i don't know why.

I will ask the Product Manager to include Power consumption details in the datasheet,  for your UPS calculations ?

I think it's 90W, but I have asked for confirmation from the Product Manager and a update to the datasheet.  My appologies for this omission, I will followup  with you as soon as I get an answer.

regards Dave

William Childs Sat, 10/10/2009 - 02:52
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Could you also have them include the BTU/hour rating. I have had customers ask for this information when designing wiring closets and sizing the proper A/C unit.



David Hornstein Tue, 10/13/2009 - 19:18
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Hi Lukasz

Excuse the pictures below, it was a cut and paste job, my apologies.

I have also attached a PDF which may be clearer, also will follow up with BTU info, which someone else wants.

I included both the 520 and 540 for other peoples reference

ESW520 Power consumption.JPG

ESW540 Power consumption.JPG

mpace1977 Tue, 12/01/2009 - 11:00
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Has this been added to the Datasheet yet? If it is, I cant find it.

mpace1977 Wed, 12/02/2009 - 10:17
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I see the table on page 7, but it's missing any info for the 48 port 540 model. I may be confused here, but it's my understanding that the number of IP phones (be they SPA or 7900) supported on a ESW switch is directly related to their power draw and the power budget on the switch. If the SPAs are taking about 10W each, then this switch should have a power capability of 480W - but that's probably not the case.

David Hornstein Wed, 12/02/2009 - 12:02
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I cut and pasted the charts that you see a little further up in this thread (as they were given to me).

There is a chart there for the ESW540-48P..who knows why that was sent to me by the BU,  and why I pasted it in, there is no ESW540-48P.

This switch series will allow  half the ports running full POE power drawn, or look at it another way,  add your SPA or 7900 phones up to the POE budget limit.

I will ask for a correction to the charts,  I don't think it's a prelude to the release a tri-speed 48 port POE switch.

regards Dave

farleyriggs Thu, 09/09/2010 - 05:52
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Hello David,

Apologies for targeting you directly with this question but you seem interested (and able) in tracking down the info we users need. This old discussion helped me answer 2 of my 3 questions regarding power requirements of various Cisco items. The last one I need is power draw/power adaptor of the UC520. Like the ESW switches in this thread I can't find it documented anywhere.

Hope you can help & thanks for your effeorts to date.




David Hornstein Thu, 09/09/2010 - 15:12
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Hi Lee,

The power supply draw for the Power Supply that supplies the UC520 is ( now I need my glasses to read it on the back of the power supply)

input 100-240VAC ~4A 

output to UC520  is 12VDC  up to 15A


dtbullock Mon, 03/22/2010 - 00:14
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As of 22-Mar-2010, the ESW 500 series data-sheet and lack of a power-calculator still fails to meet the needs of installers who need to consider the power-draw and heat dissipation of the switches from the perspective of UPS and heat management.

The main shortcoming is that under the "Power" section, it just says "24- and 48-port models: 100-240V 47-63 Hz, internal, universal;"  This information isn't much use for even the simplest of calculations.  More usefully, it would provide a Volt-Amp (VA) rating.  One could then apply a rough-and-ready power-factor (60% according to UPS vendors), to get W = 0.6 * x VA for power needs, and W = 0.6 * (input VA - PoE VA) for heat needs (since the PoE wattage is mostly dissipated away from the swtich).

Happily, this thread provides the kind of raw information which the Cisco 'classic' power calculator is probably built from.  But it's still a real hassle that I had to go Googling for it instead of finding even the basics on the data-sheet, where it belongs.

dtbullock Mon, 03/22/2010 - 01:53
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In the tables you pasted, the table for the PoE and non-PoE variants of ESW 520 24 are the same.  Also, they don't differ from each other in the same manner that thePoE and non-PoE variants of ESW 520 48 do.  Did you mis-paste?

PS.  VA * PF = W ... so this will give you the Watts you can assume are dissipated by the device as BTU/time.

daclemmo Thu, 03/25/2010 - 14:20
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SKUPS Rating (Watts)
PoE Budget (Watts)

This table shows the power supply and PoE values for the ESW switches.