-> to 70-80 Amps.  I wouldn't be surpised to see 1 AWG Al (service wire -> is 
often high temp rated, and not subject to the cooling restriction -> or 
flammables exposure of indoor wiring).  1/0 Cu would be nice.  You
 DH> Note that 1/0 Cu is only rated to 150 amps (at room temp of course).
Wire often has numerous ratings, based on temperature in an openly cooled, 
restricted, or bundled with other heat source (active conductors) 
environment, or based on thermal withstanding of anything from the wire 
itself to insulation or nearby material.  It can also be based on allowable 
loss limits.  
In power amps we're talking about transient loads except during sustained RMS 
tests, and as such may accept transients above nominal circuit ampacity.  
Speaker wire should be constrained by damping factor, and only by heat in 
such poor systems as to hardly be worthy of discussion.  
 DH> When your talking that much current, would it be practical to start
 DH> biwiring stuff, and/or using 220-240V service?  It seems easy enough to
 DH> run 2 or more 110-120V lines and hook them both up to 1 amp.  Then you
Either way, that's 240.  Ideally, in portable equipment used in systems not 
so big as to always require its own sub panel feed (like a 50 kW PA), 120 V 
15-20 A is a nice working limit.  Beyond that, go with more smaller amps that 
can have loads distributed if needed.  
 DH> can use 1/0 Cu and run an easy 100 amps per line.  Of course, if you did
 DH> that your essentially doubling voltage, correct?  Add a 2:1 (or whatever
 DH> ratio you need) transformer at the end to drop the voltage too 110V,
 DH> (making sure it can handle the amperage of course).  Actually, by the
Might as well get amps with 240 inputs then, as xfmrs resist the transient 
currents.  For a really big power amp, why not direct rectify the 13.8 kV 
lines?  It's possibly to make some several hundred kW amps with just pairs of 
tubes as finals using those voltages.    
Terry
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