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[Robert Piascik]

I doubt that I even drew 2-3 amps with my one mic and amplified acoustic guitar playing at soft volume. The gig is done and maybe there was very low voltage at the site but my X32R and powered speaker seemed to power up with no issues. There was no thought of making the power permanent at the site so it seems odd that they would have 1000-1500 ft spool of cable to be used once and then coiled back up (maybe they borrowed the spool from an electrician?) but I guess this was better than trying to run twenty or thirty 50' extension cords.

Yes, gig could have been done with a generator or battery powered equipment but this is what they provided and my questions were more theoretical as to why does a permanent installation not suffer (seemingly) the same voltage loss as running extension cords.

Thanks for all the contributions!

[Mike Sokol]

About the shed.  I have a shed 150 feet from my house and I feed it with #12 wire.  It is protected with a 15 amp breaker followed by a 7 amp fuse.  (I couldn't buy a 7 amp breaker to fit my panel.  With 120 volts in I would see 112.65 volts at the end.  All I use it for are lights and a small battery charger so I am OK.  If I needed real power out there I would have run #10 with single phase 220 on it and put a small breaker panel in the shed.

I had a similar situation perhaps 30 years ago. I had a spare 240/120 volt 2 KVA transformer in my junk box (yes, it's a big junk box), so I sent both hot legs down the 12 gauge wiring to the 240-volt side of the transformer mounted in the garage, then re-established the G-N bond on the secondary 120-volt side of the transformer along with a ground rod and fed it to a sub-panel with a 15-amp breaker.  Minimized the voltage drop on my 120-volt gear, and I didn't have to re-run the wires. Of course, that's not a cheap transformer nowadays, but it would reduce the amount of copper needed for any long run like the OP asked about. 

[Jonathan Johnson]

I had a spare 240/120 volt 2 KVA transformer in my junk box...

I have a spare 14,400/120 volt transformer, but it's only 400 VA. So far all I've managed to use it for is as a Jacob's Ladder.

[Peter Morris]

It’s also important to understand the problem is more than just voltage drop.  Under fault conditions the resistance of the cable has to be low enough to reliably trip the circuit protection.
 
e.g. 20 amps @ 110 volts = 5.5 ohms.
 
For 500 yards of extension cable there is 3000 feet of wire in the circuit. The cable has to have a resistance (much) less 1.83 ohms per 1000 foot for the circuit breaker to operate reliably.

http://www.bulkwire.com/wireresistance.asp

[Craig Hauber]

3) let's say you wanted to build a shed or gazebo or some other structure and have a few circuits at the site, how would you get power to it from the house without experiencing significant voltage loss over the long cable run?

Thanks in advance!

The only way to do that would be having the utility co provide another service.  That's 3000' and will require a few poles and another transformer, meter and service entrance.
We have many farm and oilfield clients right now and that's all we've been doing lately.  If it's one farmstead with outlying service they usually just extend utility wires from the existing centrally mounted pole and transformer.  If it's a mile or more down the road they will just pull from whatever the nearest distribution branch is.
(We are in an area where the farmers don't refer to their land in "acres" but use "square miles" instead -and it's all cropland!)

[Tommy Peel]

(We are in an area where the farmers don't refer to their land in "acres" but use "square miles" instead -and it's all cropland!)

That's a lot of land....

[ProSoundWeb Community]