
Originally Posted by
westom
Apparently assumed is that power loss is destructive. It is not. However power loss can be preceded by a surge. After all, something had to cause that power interruption.
View numeric specs for the UPS. It does not claim to protect from surges. In fact the typical UPS connects a computer directly to AC mains when not in battery backup mode. How does its relay (that takes tens of milliseconds to trip) stop surges (that are done in microseconds)? View its numeric specs. No surge protection claimed.
UPS has one function - to provide power so that data is not lost.
Another posted a popular myth:
> Computer parts are incredibly sensitive to dips or rises in voltage, and
> can certainly be damaged by them.
View industry spec numbers even before 1970 - before PCs even existed. The chart, where voltage dips occur has this phrase in capital letters: "No Damage Region".
AC electric dropping by more than 5% is harmful to motorized appliances. Computers are required to operate normally - even start up - when voltages drop 25%. Whereas electronics in the 1970s had to withstand 600 volts without damage, Intel specs require computers to withstand thousands of voltage without damage.
Since then, international standards (ie IEC1000-4-2) now require more. Interface semiconductors withstand 2000 and 15,000 volts without damage. For those who need to see published numbers, a data sheet for one such semiconductor: (sorry, the system will not let me post it in a human friendly manner)
Triple w, maxim-ic dot com, slash en slash ds slash MAX1487E-MAX491E.pdf
All computers have significant internal protection. Protection that can be overwhelmed if the homeowner lets the rare and destructive surge enter his building. That surge must be earthed which means before a surge even enters the building.
Above confront popular myths - with numbers and professional sources. Brownouts are not destructive to electronics - only a threat to motorized appliances. All appliances contain protection. Computers are required to be most robust. But if you do not earth the rare and destructive surge - if you let it inside the building - then protection inside some appliance can be overwhelmed.