The electrical codes specify wire size and current load based on HEATING the wire.

With big power amps that have large storage capacitance (High powered class A amps, for example), the current pulse when the rectified voltage forward biases the rectifier diodes and charges the filter capacitors can be huge. The AVERAGE current value can still be low so that wire heating (or fuse/breaker tripping) is not an issue but the peak current value will result in a peak voltage drop through the AC line conductors that can be several volts. A larger conductor (12 gauge instead of 14 gauge, for example) will lower this voltage drop and allow more AC line voltage to get to the supply of the audio product, where it is needed.

Paul

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the 1derful1