Disclosed herein is an apparatus for detecting an arc fault, which
prevents a malfunction caused by a conventional current detecting method
by detecting a source voltage applied onto a conductive wire to determine
whether there is an arc fault, prevents a malfunction with respect to a
pseudo arc signal by dividing a current detecting route into two
according to the magnitude of a load current occurring onto the
conductive wire to determine whether there is the arc fault by voltage
detection, and lessens the danger of a fire by reducing a circuit break
time according to the magnitude of the load current. A voltage detector
detects the arc fault by use of two detecting routes. Each route differs
in a filtering value of a filter, presence/absence of level limit, an
amplification factor of an amplifier, an accumulation value of a
comparator, etc. according to the magnitude of a load current occurring
on a conductive wire, thereby reducing a circuit break time.