Ron. Did you read your citation before posting it? Where
is the reference to common mode protection? Where are any
numbers that apply to common mode protection? Once APC used
to provide far more numbers when they claimed to protect from
Normal mode transients. Now they don't even make those
claims. Numbers provided by Ron's citation:
Surge energy rating (one time, 10/1000 µs
waveform): 160 J.
Surge current capability (one time, 8/20 µs
waveform): 6500 Amp peak maximum.

Hell. They don't even list dBs for the noise filter. What
kind of spec is that? Noise filter for what? Incoming AC
line? Output power line? Clearly these are specs for the
technically naive.

After one surge, the entire UPS is toast? Look at those
pathetic numbers. Only 160 joules? Only 6500 amps?
Effective protection starts at about 1000 joules and 50,000
amps. Thank you Ron for demonstrating pathetic protection
from that plug-in UPS.

Oh - where do they mention anything about 'faraday cage'
protection?

In the meantime, Ron describes normal mode protection:
In order to protect a device from an undesirable voltage
arriving over the power cable one simply shunts that unwanted
voltage such that it appears equally on all the wires on that
power cable ...

Where is the common mode protection? Not in that citation.
Not in what Ron describes. Just another reason why that
plug-in UPS does not provide effective protection.

Ron Reaugh wrote:
"w_tom" wrote in message
...
Ok sir. Explain to us how a plug-in UPS provides common mode
protection. Also cite the manufactuer's spec that claims that
common mode protection (and good luck).

No problem. He
http://sturgeon.apcc.com/techref.nsf/partnum/990-7015/$FILE/7015-1.pdf
Section 9.4

Do you understand what common mode means with respect to the
above spec and do you understand how that differs/same as
the general concept of common mode and how that relates to
these issues?

In order to protect a device from an undesirable voltage
arriving over the power cable one simply shunts that unwanted
voltage such that it appears equally on all the wires on that
power cable i.e. AC-hot, AC-neutral and the ground wire
which connects to the chassis of the device. That shunt is
done with capacitors and surge diodes or MOV devices etc. or
in the old days on your phone line with a spark gap. That's
basically what a surge suppressor does. The device's input
components therefore see no intolerable VOLTAGES and it
survives. It makes no difference to the device if the whole
device(chassis and all) jumps to a million volts during the
episode. Ever heard of a Faraday Cage?
...