Which voltage level has more insulation in transformers?

• A. High voltage
• B. Low voltage
• C. Both equally
• D. Neither

Answer: (A)

Insulation thickness and creepage distance scale with the voltage the winding must withstand. The high‑voltage winding carries a larger potential difference relative to the other windings and to ground, so it faces greater electric stress. To prevent breakdown and arcing, it is designed with more insulating material, greater spacing between conductors, and robust barrier layers. The low‑voltage winding operates at a smaller voltage difference, so it needs less insulation. This is why the high‑voltage side is the one with more insulation.