To Compute system current draw requirements
you must first ascertain the approximate current draw (in amperes) of the load (your amplifier or amplifiers). Calculate the total power of each amp by multiplying the number of channels by the number of RMS watts per channel). If you have multiple amps, add up the total power figures to arrive at a grand total. Second, double your grand total power figure. And, last, divide by 13.8. The result is your system's approximate max current draw in amperes. Typical examples are below:

Current in this case, is the maximum amount of pre-clipping amperes drawn. With all amplifiers, in the quiet state, less than an ampere may be consumed. Power drawn is proportional to signal amplitude on an exponential curve. System wiring should always be configured for the highest rated consumption usage.