Sizing a UPS solution is a simple mathematical formula
multiplying power (volts) and current (amps) to eventually come up
with the load rating VA (volts x amps). Another method for obtaining
load is by obtaining the watts rating. Here are some steps to get
Step 1 List all the equipment to be
protected by the UPS in one column. Examples are computers,
monitors, modems, PBX phone systems and other network hardware.
Step 2 Read the nameplate on each of
the pieces of equipment and write down the volts and the amps next
to each piece of equipment using another column. An example would be
120V and 2.0A.
Step 3 Multiply the volts and the
amps of each piece of equipment and enter the total in a column
labeled as "VA". When the equipment is only rated as watts, convert
it to VA by multiplying that figure by 1.43 and enter it in your
Step 4 Its recommended once you
have the total VA load to add an additional 25% to that figure to
accommodate any future growth. Its also a good safety precaution to
avoid the potential of overloading a UPS.
Step 5 Once you have the total VA
load add an additional 25% to that figure to accommodate any future
growth. This is also a good safety precaution to avoid the potential
of overloading a UPS.