For reference, definitions of "qualified" and "qualified person" with regard to on the job training from various codes and standards:
NFPA 70 (2014)
Qualified Person. One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved.
NFPA 70E (2015)
Qualified Person. One who has demonstrated skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training to identify and avoid the hazards involved.
CFR 1910.399
Qualified person. One who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved.
NOTE 1 TO THE DEFINITION OF ??QUALIFIED PERSON:?? Whether an employee is considered to be a ??qualified person?? will depend upon various circumstances in the workplace. For example, it is possible and, in fact, likely for an individual to be considered ??qualified?? with regard to certain equipment in the workplace, but ??unqualified?? as to other equipment. (See 1910.332(b)(3) for training requirements that specifically apply to qualified persons.)
NOTE 2 TO THE DEFINITION OF ??QUALIFIED PERSON:?? An employee who is undergoing on the-job training and who, in the course of such training, has demonstrated an ability to perform duties safely at his or her level of training and who is under the direct supervision of a qualified person is considered to be a qualified person for the performance of those duties.
IEEE C2 (2012)
Qualified. Having been trained in and having demonstrated adequate knowledge of the installation, constmction, or operation of lines and equipment and the hazards involved, including identification of and exposure to electric supply and communication lines and equipment in or near the workplace. An employee who is undergoing on-the-job training and who, in the course of such training, has demonstrated an ability to perform duties safely at his or her level of training, and who is under the direct supervision of a qualified person, is considered to be a qualified person for the performance of those duties.