The maximum PoE capacity of the switchports on the UC520 and UC540 is 88W total and up to 15.4W per switchport.

The show power inline command on the UC520 and UC540 will show you the actual power usage of each of the switchports. Here is an example of output of this command:

sample-uc520#sh power inline
PowerSupply   SlotNum.   Maximum   Allocated       Status
-----------   --------   -------   ---------       ------
INT-PS           0        88.000    47.000          PS GOOD
Interface   Config   Device    Powered    PowerAllocated
---------   ------   ------    -------    --------------
Fa0/1/0     auto     Unknown  Off        0.000 Watts
Fa0/1/1     auto     Unknown  Off        0.000 Watts
Fa0/1/2     auto     IEEE-3   On         7.000 Watts
Fa0/1/3     auto     IEEE-3   On        12.000 Watts
Fa0/1/4     auto     IEEE-3   On         7.000 Watts
Fa0/1/5     auto     IEEE-3   On         7.000 Watts
Fa0/1/6     auto     IEEE-3   On         7.000 Watts
Fa0/1/7     auto     IEEE-3   On         7.000 Watts