zam
Member
- Location
- New York, NY
I need some assistance interpreting Section 450.21 (B) (Exception 1). Can the fire-resistant, heat-insulating barrier between the transformer and the combustible material in this case be a wall with a minimum fire rating of 1-hour? Also, is it correct to say that a fire-resistant, heat-insulating barrier is not needed if the combustible material is located more than 6-feet away horizontally and more than 12-feet away vertically from the transformer? The transformer in question will have a rating of more than 112.5 kVA, and it will have a class 155 or higher insulation system with copper winding. Thank you.