The voltage tester does not detect any voltage.

Cause: The operator is not holding the voltage tester firmly or is wearing gloves during the voltage testing.

Remedy: Hold the voltage tester in your hands without gloves.

Cause: The wire being tested is partially laid underground or is in a grounded metal wire.

Remedy: Find an appropriate location without a ground fault to take the measurement.

Cause: The magnetic field generated by the voltage source is being interfered with or it is being suppressed.

Remedy: Eliminate the fault.

Cause: The voltage tester is not being used in accordance with the technical data.

Remedy:  see Technical data.