Understanding Volt AMP (VA) rating:

The VA rating of your unit represents the volume of electricity that the unit is designed to protect. Exceeding the VA rating of your ups is a common cause of UPS problems, even when the power is not out.

How does it work?

The VA rating of the unit is similar to the circuit breakers in your home that protect you from overloads – most breakers are 15amp breakers, meaning that you should not ever plug in enough devices to use more then 15 amps of power, or the breaker will trip, and disconnect the load. Without this safety, you risk a fire by causing the wires in the wall to heat up to the point that they ignite and burn. The same basic idea works with your UPS VA rating – the components inside your UPS are designed to never have a load higher then the VA rating, so overloading the UPS can damage the internal components, creating a risk of fire and damage to equipment. Think of your VA rating as the redline on an engine- you can rev it up to the max rating, but exceeding it, or even just running it for long periods near the redline will shorten the life of the engine, or even cause it to fail.

How do I make sure I am not overloading my UPS?

If your load indicator reads more then 60%, you should upgrade your unit to a higher VA unit. When choosing a unit, keep in mind that you want your baseline load to be about 50% of the UPS capacity, to allow your unit to perform best. This means that if I have a 500 VA load from my pc, monitor, and internet connection, I would look for a UPS rated for at least 1000 VA.

How do I figure VA of load?

RefurbUPS.com provides a useful UPS sizing utility that will help you identify what VA load you have on your current UPS, and what size UPS you need to be safe here:

UPS Sizing Calculator