This table shows the amount of current flow which will cause a 1/2 volt drop in a 15 foot run of cable. Many people consider 1/2 volt to be the maximum acceptable voltage loss in a system's main power wire. The 'total amp power' is the total maximum unclipped RMS power output‡ of all of the amplifiers combined. It is based on 60% efficiency (for class AB amplifiers) and a battery voltage of 13.8 volts.
‡ For all of the calculators and tables on this page, unless otherwise noted, 'max power' is the RMS power output when the amplifier is on the threshold of clipping.
These are the recommended maximum fuse ratings for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe.
Please note that the recommended fuse ratings are roughly based on 300 circular mils (explained at the bottom of the page) of copper per amp of current. Others may suggest slightly different fuses for a given wire size but these should be generally recognized as safe in most all situations.