5412R ZL2 - Power Consumption & UPS sizing

[I Philip]

We have a 5412R ZL2 chassis providing 188 x 1Gbps PoE+ access ports with 2 x 10GBaseSR uplinks.

The chassis is powered by 2 x J9829A PSU's each capable of providing 1100W of PoE+ power.

It is envisaged that no more than 400W of PoE will be required.

We need to specifiy a UPS to provide 30 mins of backup in the event of a power outage.

We are having trouble in ascertaining the power consumption of the 5412R switch.

On the one hand the specs for the PSU module says @ 240V it could draw 6.8A MAX - which would indicate a power consumption of 1632Watts

Then on the other hand a Tolly test report implies that the average power consumption for a fully loaded 5412R ZL2 switch with 2 PSUs is only 824Watts

Does anyone have experiance of acurately sizing UPS's for HP switches ?

Any assistance would be much appreciated.

Thanks