Q4. What are the requirements in locating transformers above a suspended ceiling?
A4. Dry-type transformers, rated not more than 50 kVA, are permitted above suspended ceilings or in hollow spaces of buildings, if not permanently closed in by the structure [450.13(B)]. Dry-type transformers not exceeding 50 kVA with a metal enclosure can be installed above a suspended ceiling space used for environmental air-handling purposes [300.22(C)(2)].
Per the question and answer newsletter; It appears from the answer that a 75KVA transformer cannot be installed above a suspended celing. 450.13 B says permanently closed in by structure. The removeable ceiling tiles are accessible or are they permanent So is a transformer allowed to be installed above a suspended ceiling