Maintenance of electrician training is a kind of vocational skill education, which is an educational course offered by professional training institutions. Vocational skill appraisal is an assessment of vocational skill level, which is divided into practical operation and theoretical examination. Advanced skill appraisal requires certain work experience and theoretical level, which is the assessment basis for the certificate of junior, middle and senior skill level issued by the Ministry of Labor. Different classes in training institutions may be different.