Which type of transformer is typically used in underground pad-mounted installations?

• A. Overhead distribution transformers
• B. Pole-mounted transformers
• C. Pad-mounted underground transformers
• D. Substation transformers

Answer: (C)

Underground pad-mounted installations require equipment that sits at ground level in a weatherproof, secure enclosure. A pad-mounted underground transformer is designed for this setting: it is installed on a concrete pad at grade, protected by a durable enclosure, and wired to underground feeders. This arrangement keeps the transformer accessible for maintenance while safely isolating it from the underground network and passersby, which is ideal for urban, buried distribution.

Overhead distribution transformers are built for mounting on poles or other above-ground structures and connect to overhead lines, not to buried cables. Pole-mounted transformers sit on utility poles, again above ground. Substation transformers are large units used inside substations or on-site facilities, not the compact pad-mounted style used for underground networks.