Which of the following provides clearance requirements from walls for proper ventilation of transformer enclosures?

• A. the NEC®
• B. job specifications
• C. manufacturer's nameplate
• D. all of these

Answer: (C)

When you install a transformer, the exact wall clearance needed for proper ventilation is given by the transformer’s nameplate and installation instructions. The nameplate lists the minimum distances to walls and surrounding equipment that are required to maintain adequate airflow and allow service access, which are specific to that model’s cooling design. While NEC provides general installation guidelines and job specs may add project requirements, they don’t replace the unit-specific clearances printed by the manufacturer. Following the nameplate ensures the transformer can ventilate properly and operate within its thermal limits.