A UPS is used to supply power in the event of a power loss, to either allow you time to save what you are doing and properly shut down. A number of them have software as well, which will allow your computer to properly shut itself down.
They also do a great job as automatic voltage regulators, providing much cleaner and consistent power. And, they are also functioning as a surge protecter.
As noted before, backup power in the event of a full power outage is really just the icing on the cake. This is why the comments about no lightning storms or severe weather in their areas, or their power is stable really just illustrates a lack of awareness of the problem and the need for a good UPS.
Bad weather is NOT, by any means, the only source of damaging power anomalies. Neither is the power grid!
It is the power anomalies we cannot see without sophisticated test equipment that justifies the use of a "good" UPS.
Even in ideal conditions,
every time your refrigerator or AC cycles on and off, it is sending surges and dips down the line. When these appliances are working properly, these individual anomalies cause no damage and our PSUs are designed to deal with them. But they are still constantly banging on our supplies and their regulator circuits, wearing them down and aging them.
If you don't place any value on your hardware, don't care if your network stays up, and don't care about your data, then fine. You don't need an UPS. But if you can justify in your head to use a surge and spike protector (and everyone can) then the same justification can be used for a good UPS.
Also, because a "good" UPS with AVR uses "intelligent" (active) circuitry to monitor and regulate the incoming voltage, it's surge and spike protection does not wear out over time. But a surge and spike protector uses MOVs, passive devices that do wear out - at which point their surge and spike protectors turn into simple power strips.
See
NMSU Safety Article, Information About Surge Protectors,
NMSU.edu said:
The MOV is the heart of surge suppressors. The role of the MOV is to divert surge current. However, MOVs wear out with use. As more surges are diverted, the MOVs life span shortens, and failure becomes imminent.
There is no forewarning or visual indications given - just failure. And while failing, they can reach very high temperatures, and actually start fires.
It has been said that a surge and spike protector is like a motorcycle helmet. After it saved your noggin once, it is time to get a new helmet.
Sadly, because the first UPSs from years ago were only for backup power during power outages, that stigma has stuck in the minds of many. But today, that's like saying your cell phone is only for making phone calls! And that is far from the truth.
That would be me.
Thanks for your service.
And for yours too. And to clarify, I don't want to forget the "Silent Service" of the USN and our allies either. Especially today, the Fourth of July.
Edit add: As for EMP, that depends on the amplitude - but generally, YES. Because EMP introduces large surges into circuits, a good UPS can protect from EMP from the line voltage - assuming there is anything left to protect after a nuclear blast. But since the EMP can be introduced directly into the computer circuits too, the point is pretty moot.
