New York State Master Electrician Practice Exam

Dry type transformers rated over 35KV must be installed in a vault due to safety and fire protection considerations. A vault provides a controlled environment that minimizes the risk of fire hazards, ensuring that any potential electrical fault does not spread to surrounding areas. This type of installation helps prevent the transformer from being exposed to environmental factors that could compromise its operation. Additionally, vaults are designed to contain any potential leaks from the transformer, providing an extra layer of safety.

The design and construction of the vault also adhere to specific codes and standards that dictate fire resistance and access control, further enhancing the safety of high-voltage installations. Such provisions are crucial, especially in urban or industrial settings where high voltage equipment can present significant risks. Therefore, installing dry type transformers over 35KV in a vault is a regulatory requirement that prioritizes safety and compliance within electrical installation practices.