[Amps] Benefits of 3-phase power?

[R.Measures]

>Hi Bill and everyone else interested!
>
>My comment "surprising it's working at all" is among other things relating
>to a typical house installation in North America. A cobb web of wires
>criss-crossing through beams and joists, no conduits for the wires, cheap
>components and generally cheap installations. Everything in order order to
>save a buck or two. Electrical safety here has still a long way to go.
>
>At one point in 1970s the house builders went totally crazy and installed
>aluminum wiring to save even more money. Fortunately they had to stop that
>practise as it caused too many house fires and the insurance companies
>refused to cover damages.

Aluminum wire works OK if one uses connectors that are  specifically 
designed for that purpose. and the aluminum wire-gauge is c. two gauges 
heavier than would be used for copper wiring.   In the United States, 
aluminum is typically used in high current circuits, such as the 100A 
mains coming into a house, but copper is used for distribution to 
lighting, wall outlets, and the like inside the house.  
-  Aluminum is also used for long distance tranmission lines since it has 
more conductivity per unit weight than copper.  
>
>Some basic facts about 3 phase....  Most of the electric power in the world
>is 3 phase.  The concept was originally conceived by Nikola Tesla and was
>proven that 3 phase was far superior to single phase power.
>
>3 phase power is typically 150% more efficient than single phase in the same
>power range.  In a single phase unit the power falls to zero three times
>during each cycle. In 3 phase it never drops to zero.  The power delivered
>to the load is the same at any instant. Also, in 3 phase the conductors need
>only be 75% the size of conductors for single phase for the same power
>output.
>
>Using three conductors (rather than two, as used for single phase power)
>allows for lower current levels in each conductor, again facilitating the
>use of smaller conductors. For this and other reasons, three-phase power
>simply provides a more efficient means of supplying power to large
>electrical loads as well as typical residential dwellings.
>
>Likewise, if one is running, say, 5-10 kVA, it's a lot easier to find
>components to
>handle the 15-20 amps per phase, rather than handling the 50 amps you'd need
>for single phase.  When handling currents over 20-25 amps, everything gets a
>LOT more expensive: switches, variacs, fuses, fuseholders, plugs and
>sockets, etc.  There's a good reason why three phase is popular for loads
>over a few kW, especially if you start pricing good  plugs and receptacles
>to handle 10 kVA, (i.e. not stove/dryer plugs which are really designed to
>be plugged or unplugged a few dozen times, at most).
>
>3-phase power doesn't "have it's advantages" it's superior to 1- and 2-phase
>systems.
>
>There is a lot more to be said about 3 phase power. Maybe some other time.
>
**  V-12 engines are clearly superior to the wimpy 4-banger in my 
Corolla, but puttin' gas in it doesn't take a bankrolla.  
-  This computer and desk lamp run on single-phase.  Some things are more 
suited for three-phase, some things are not.  For linear amplifiers, 240v 
single-phase is OK for up to  c. 15k out the door.  Although the 
anode-supply filter-C would cost more for single-phase, a three-phase HV 
transformer would cost more.