Sparky5150
Member
Is it mandatory?
What if there is a transformer?
What if there is a transformer?
II. Specific Provisions Applicable to Different Types of Transformers
450.21 Dry-Type Transformers Installed Indoors.
(B) Over 1121/2 kVA. Individual dry-type transformers of more than 1121/2 kVA rating shall be installed in a transformer room of fire-resistant construction. Unless specified otherwise in this article, the term fire resistant means a construction having a minimum fire rating of 1 hour.
Exception No. 1: Transformers with Class 155 or higher insulation systems and separated from combustible material by a fire-resistant, heat-insulating barrier or by not less than 1.83 m (6 ft) horizontally and 3.7 m (12 ft) vertically.
Exception No. 2: Transformers with Class 155 or higher insulation systems and completely enclosed except for ventilating openings.
Sparky5150 said:Exception No. 2: Transformers with Class 155 or higher insulation systems and completely enclosed except for ventilating openings.
Dont most standard dry type transformers over 112.5 meet this exception?
I think this code is highly misunderstood.