Who is permitted to install and service transformers?

The correct answer indicates that only qualified persons are permitted to install and service transformers. A qualified person is defined as an individual who has received training, experience, and knowledge sufficient to install and maintain electrical equipment safely and in accordance with the applicable codes and standards. This requirement is crucial for transformer work due to the complexity and high voltage involved, which can pose significant safety risks if not handled properly.

While individuals with basic electrical knowledge may have some understanding of electrical systems, they do not possess the necessary training or expertise to work with transformers specifically. Electricians, while trained, are not the sole group permitted unless they meet the qualifications necessary to work on transformers. Additionally, the term "all licensed contractors" could imply individuals who may have licenses in various fields but not necessarily the specific qualifications required for transformer work. Thus, the emphasis on qualified persons ensures that only those with appropriate training and expertise are authorized to perform such tasks safely and effectively.