\rThe size of your amplifier power wire will depend on the amount of current your amplifier is drawing from the battery. Typically, you double the RMS output of each amplifier, and divide by 13.8. This will tell you the total amount of current your amplifier setup is drawing from the battery. From there, if you are running more than 1 amplifier, each amp will need power from the distribution block based on the current draw of each specific amplifier. In general if it is under 400 watts RMS, 8 AWG. If it is 400W-1200W you can use 4AWG. If it is 1200-1500W use 2 AWG. If it is over 1500 watts, use 1/0 AWG. These are general statements. Please double check your amplifier's current draw, your total system current draw, and the distance from the amplifier to the battery if you want to be very specific.\r\r