While looking around for more info on this, I ran across this:

http://jpaa-en.apc.com/app/answers/detail/a_id/1372

"Surge protectors filter the power for surges and offer EMI/RFI filtering but do not efficiently distribute the power, meaning that some equipment may be deprived of the necessary amperage it requires to run properly causing your attached equipment (computer, monitor, etc) to shutdown or reboot."

Huh? I've never, ever, seen a surge strip do that (unless I operate the switch on it). Are they saying something like I can't get more than a couple amps from the last outlet? Of course they want you to buy their overpriced PDUs so they can get a few hundred dollars more out of you.

"Plugging your UPS into a surge protector may cause the UPS to go to battery often when it normally should remain online. This is because other, more powerful equipment may draw necessary voltage away from the UPS which it requires to remain online."

I have no idea what they are talking about, unless it is stuff like a big air conditioner, which I suppose would cause problems on a little UPS.

This all comes from a company that told me their 208 volts commercial UPSes are not grounded and don't need to be grounded. Apparently they are not grounded. Other manufacturers (Tripp-Lite, Eaton) do ground theirs. I no longer buy APC products (as of a few years ago).