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Support - Sizing a UPS

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 you started:

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 "VA" column.

Step 4 It’s recommended once you have the total VA load to add an additional 25% to that figure to accommodate any future growth. It’s 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.