sentences:  It is not unusual to measure phantom voltages of 50–90 volts when testing the wiring of ordinary 120 V circuits with a high-impedance instrument.While the voltage produced may read almost to the full supply voltage, the capacitance or mutual inductance between the wires of building wiring systems is typically quite low and incapable of supplying significant amounts of current.However, in overhead transmission work on or near high-voltage lines, safety rules require connecting a conductor to earth ground during maintenance, since induced voltages and currents on a conductor may be sufficient to cause electrocution or serious injury.