A fault indicator for indicating the occurrence of a fault in an electrical conductor
has a plurality of trip settings, such as in the range of 50 A to 1200 A, that
is automatically calibrated. The fault indicator includes a housing, a battery,
an illuminated display, such as LEDs, a current sensor for sensing the load current
in the conductor and a microcontroller that receives a current signal from the
current sensor to determine the load current. In the calibration mode, a known
load current is passed through the conductor, the microcontroller selects the trip
level that is related to the load current, determines the load current from the
current signal, and sequentially calibrates each of the plurality of trip levels
for the respective known load currents. The calibration information is stored in
memory. The illuminated display provides a distinctive pattern to indicate that
each trip setting has been calibrated.