Due to wire resistance
Due to high current flow
Due to elastic property of insulation
Due to the strength of the wire material
Current
Voltage
Resistance
Frequency
1.5 V to 2.2 V
2.3 V to 3.6 V
4.5 V to 5.5 V
5.0 V to 7.5 V
Measure current
Measure voltage
Measure diameter of wire
Measure insulation of wire
Insulation resistance