Dedicated 20a lines, 125 feet distance, which gauge wire to run?


Want to set up 4x dedicated 20-amp lines for my hifi system. The distance from the outlets to the breaker box is about 125 feet. What wires should I use? 10, 8, or 6 gauge? And should they be solid or stranded? If you could be as specific as possible that would be appreciated (brands, links, etc), as I am out of my depth here. The wire will need to run underground for a good portion, and then into craw space, if that makes any difference.
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Showing 1 response by towertone

First thing you should do is figure the current draw for your equipment. 
A little overkill is ok but why get carried away?

In a previous job I rewired our ISP buildings with #10 stranded for all 110 VAC circuits, always with a separate neutral (no sharing with other circuits). This was in case we ever needed to change an equipment rack from 110 to 220 (or possibly 208). And yes, stranded handles more current and dissipates heat better.  

Also a common mistake in sub-panels, whether 110 or 220 is bonding the neutral to ground. The is the rule in a main panel but a no-no for sub-panels.