Why is alternating current used for domestic purposes?
Alternating current is easier to distribute than direct current,
because alternating current can be raised or lowered in voltage by
a transformer. This allows very high voltages to be used in long
distance transfer of electricity, which is then stepped down
several times before being supplied to the end user. As the voltage
is increased in a circuit, the current, as measured in amperes,
decreases for a given load. This allows the use of lighter wire to
transmit large amounts of electricity.