WS-C3850-48U Power Consumption

[mmcgurty]

So we recently installed a (2) switch Cisco WS-C3850-48U (UPOE power) stack in an IDF closet for our NYC offices.  These switches have dual 1100W power supplies installed in them.  Now, when they planned this space no thought to add a UPS.  They just told the electrician to install a (4) NEMA 5-15R outlet on the way for each of the power cords out of the (4) 1100W power supplies.  These switches currently have (22) powered devices off them of various types (Cisco AP's, Cisco POE desktop switches, Cisco phones, and some non-Cisco security devices).  This will grow but not a whole lot more (maybe another 20 devices total).

Now my problem is I walked into this and see there is no UPS for this IDF closet.  I talked to APC and they want us to install (2) SMX1500RM2UNC UPS'es that are around $1200 each.  This is because they are taking into consideration a full 1100W load from each switch but I know they cannot be pulling that much wattage for 22 POE devices and for switch operations itself.

Does anyone have a good way that I could monitor this from inside the switch or with some other device on-site.  I am thinking of using a Kill-A-Watt device to measure the draw for all the secondary power supplies on (2) Cisco WS-C3850-48P (POE+ versus UPOE) we have in another facility but it doesn't have as many POE devices off of it and they aren't as new so they don't use as much power either.  It isn't a 1:1 measurement.  My options are figure out if I need those (2) APC UPS'es or get an electrician back in and add a NEMA L6-20R so I can plug in a larger UPS that can support these on one chassis.

Maybe it is just me but I feel this is a facilities issue and not a networking issue...but that is just my two cents.  Any input or ideas would be appreciated.

[icecream-guy]

APC has a real nice UPS calculator that might help with the information you need.

[mmcgurty]

I think I answered my own question using the Kill-A-Watt device on the outlet with the secondary power supplies unplugged while the primary power supplies were plugged into a power strip into my Kill-A-Watt device.  I measured 370VA for the two switches.  I added 25% to this number for the UPOE versus POE+ and then doubled it for worst case scenario on additional POE devices.  Total was 925VA, which should fit me in a bunch of models from APC.

[config t]

Maybe it is just me but I feel this is a facilities issue and not a networking issue...

Funny how facilities issues quickly become networking issues.

[icecream-guy]

Maybe it is just me but I feel this is a facilities issue and not a networking issue...

Funny how facilities issues quickly become networking issues.

ahem, first off, everything is a networking issue.
once we prove it's not the network, then we solve the other groups problems.