how to connect power for amps

“All of your components should have a label on the rear panel indicating maximum current draw in Amps...”

Another way to look at this is determine the amount of watts each component uses at idle as well as full power and use that to base your judgment. For example, a 15 amp circuit can handle an absolute maximum of 1800 watts (15ampsx120volts) and the normal operating condition should be less than 80% of that maximum. It’s much more common to see the watts usage in the equipment specs since the maximum ampere draw spec is somewhat meaningless and depends on the load. If your amps run in Class A, you should account for their maximum wattage (not watts per channel) since they’ll draw maximum current even when sitting idle.
One comment: You may want to consider placing your monoblocks close(er) to your speakers which might make this topic somewhat moot.

P.S. Your DAC and your preamp, if SS, will need little power/watts. 

In US, most if not all the backbone wiring in single family homes is 12awg and in many cases the wire from the panel is shared across multiple outlets. Electrically speaking, putting a short 10awg "pigtail" at the end of a very long 12awg wire is somewhat pointless and for most applications a good quality copper 14awg wire is more than adequate. Now if you are trying to plug an arc welder into your/same wall plug, then that's whole different story...