Transformer selection should start with a site survey, because two units with the same electrical rating may require very different rooms, foundations, clearances, and safety provisions. The transformer selection should be reviewed together with the stated application and order requirements.
For an indoor dry-type unit, record room temperature, ventilation openings, airflow obstructions, dust, humidity, altitude, fire classification, acoustic limits, cable approach, and the route for moving the equipment into position. These observations shape enclosure protection, cooling method, temperature-rise limits, and maintenance access. This transformer selection route is especially important when the equipment is installed close to occupied or process areas.
For an oil-immersed unit, the survey expands to foundation loading, oil containment, drainage, radiator clearance, bushing safety distance, lifting access, fire separation, and inspection space around gauges and valves. Outdoor exposure may also require review of wind, precipitation, contamination, solar heating, and corrosion protection. The transformer selection can then account for both the active electrical assembly and its external cooling arrangement.
Electrical information remains essential: system voltage, frequency, maximum demand, starting current, load growth, impedance, fault level, tap range, vector group, protection, and earthing. Cable or busbar positions should be checked against the room layout before drawings are finalized. A complete the product record links each rating to a confirmed operating or installation condition.
The final review should document responsibilities for ventilation, civil works, containment, fire protection, electrical interfaces, monitoring, commissioning, and routine inspection. Using one coordinated checklist makes the product easier to verify and reduces late changes during installation.