Dedicated Transformer Room

[zam]

Greetings. As per NEC article 450.21, section B: Transformers over 112.5 kVA rating shall be installed in a fire-rated transformer room. What should be the minimum size of this room OR what should be the clearance requirements around the transformer in order to determine the size of the room? Thank you.

 

[zam]

Greetings. As per NEC article 450.21, section B: Transformers over 112.5 kVA rating shall be installed in a fire-rated transformer room. What should be the minimum size of this room OR what should be the clearance requirements around the transformer in order to determine the size of the room? Thank you.

Article 450.21, section B also comes with two exceptions, but the architect has agreed on creating a dedicated room. Just need the estimated dimensions or clearances around the transformer.

 

[infinity]

The clearances should be determined by the transformer manufacturer.

450.9 Ventilation. The ventilation shall dispose of the
transformer full-load heat losses without creating a temperature rise that is in excess of the transformer rating.
Transformers with ventilating openings shall be installed so that the ventilating openings are not blocked by walls or
other obstructions. The required clearances shall be clearly marked on the transformer.