8 gauge on a speaker wire? That is waaaaaay overkill! IF the speakers are 8 ohm, and it's not a very long run, then 18 gauge will be sufficient. If the impedance is lower, then you need to increase the wire size some. You really should never need larger than a 14 gauge for any thing. I have run 2 ohm speakers kicking over 600 watts per channel on 14 gauge. Hint.... In some applications, those nice orange extension cords make great speaker cable, all in a neat bundle. Just cut the plugs off of the ends, and add the ones nedded :)