I am assuming you are going to use only one twisted pair (out of the 34 available) for 1 A. In that case, you should be fine for your application using 28 AWG copper assuming that your cable is surrounded by open air at 30 °C or cooler. The first link's recommendation is close to the (United States) National Electric Code formula. Note that the fine print for the second link says that the power transmission values are "very very conservative."
If more than one twisted pair is carrying a significant amount of current or the cable will not allow heat dissipation, use multiple pairs to carry your current.
How can be, that cable witch is less than 1mm2 can handle larger load than 17 AWG?
Or my computer cable has different measurement system used? Or listed 16A mean peak only?
It can't be.
16A/250V on your photo is just plug rating, not whole wire rating. Check other end of wire - it may have 10 or 20A rating :)
And how i can actually calculate max cable load by cable area (mm2)?
You can use some table. Table you mentioned (AWG Sizes and Current Limits) has a note:
Current (Ampacity)
The current ratings shown in the table are for power transmission and have been determined using the rule of 1 amp per 700 circular mils, which is a very conservative rating.
For reference, the National Electrical Code (NEC) notes the following ampacity for copper wire at 30 Celsius:
14 AWG - maximum of 20 Amps in free air, maximum of 15 Amps as part of a 3 conductor cable;
12 AWG - maximum of 25 Amps in free air, maximum of 20 Amps as part of a 3 conductor cable;
10 AWG - maximum of 40 Amps in free air, maximum of 30 Amps as part of a 3 conductor cable.
http://en.wikipedia.org/wiki/American_wire_gauge
Or AWG Sizes and Current Limits table is wrong?
These are many tables, maximum currents are calculated with diffrent rules. There are NEC standards, IEC standards, cable manufacturers standards, some local rules in many countries in the world. I think IEC is not bad idea for reference, but you can use any other reliable organisation or company.
Here is wire calculator based on "IEC 60364-5-52: Low Voltage Electrical Installations (2009)" standards (low voltage is < 1kV in IEC nomenclature).
General question - does installed 1mm2 cable will be good enough for that load ?
For 8 camera power supplies (probably not more than 50W total) and 190W TV - this is more than enough. These camera power supplies have 3A/220V rating, but 3A is peak current.
Additional note:
If you have a lot voltage converters connected to one UPS - turning them on all at once may cause very high pulse current and your UPS may have problems with startup.
Maybe it doesn't matter for 8 small camera power supplies and 1 big TV, but you should know.
3A on your camera power supply is pulse current for charging converter input capacitor.
Best Answer
It may depend on the sort of signalling you are using, and on your definition of AC.
For true RS-232 serial communications, a "1" bit is represented by a negative voltage, and a "0" is represented by a positive voltage, so you might call that AC - but it is a series of pulses, and stays negative when the line is idle (no characters being transmitted).
For many other serial protocols, the signal does not change polarity, but is still a series of pulses. Whether you consider this AC with a DC offset or pulsing DC is up to you.