The other question for the technical experts is how many surges can an APC 600 or other UPS handle before it goes bad?
Imagine two light bulbs connected to a common AC receptacle. When one goes bad, does the other stop working? Of course not. That is how the UPS works. One 'bulb' represents a protector. The other 'bulb' is power provided to a computer or printer. Protector circuits can completely fail. And it still connects a computer or printer directly to AC mains - no power interruption.
Every useful answer includes numbers. A potentially harmful surge is hundreds of thousands of joules. How many joules does the UPS claim to absorb? Hundreds? Near zero protection inside a UPS means advertising can hype it as 100% surge protection. Advertising fables manipulate consumers who ignore numbers. Spec numbers identify a UPS that is only near zero protection.
UPS connects a printer or computer directly to AC mains when not in battery backup mode. It switches to batteries and creates 'dirty' power during rare power outages. That function continues even if protector circuits have failed. A consumer would never know. Since superior protection, already inside each appliance, remains functional. And that UPS still outputs power.
Expect a UPS battery to seriously degrade or completely fail every three years.
