5.2 All equipment shall be suitable for continuous operation twenty-four (24) hours per day, seven (7) days per week and three hundred sixty-five (365) days a year. The equipment shall be designed for outdoor or indoor application installed in dry, clean and well ventilated electrical room. 5.3 All equipment, components and materials furnished shall be new, of premium quality and of essentially heavy-duty design, either meeting or exceeding the requirements of this Specification. 5.4 All equipment and components shall be of recent manufacture and standard design, for which replacement parts and service are available. 5.5 Unusual Shipping Conditions. The switchgear will be transported on a rough narrow-winding gravel surface road with many grades in excess of 25%. While securely installed on a skid, it may be transported up the slope by a tractor push-pull arrangement. The Vendor shall provide the necessary bracing, and securely fasten all accessories attached to the enclosures so that damage to the switchgear will not occur during transit. 6. TECHNICAL REQUIREMENTS 6.1 The Power Transformer ratings and accessories shall be as indicated on the attached Data Sheets 6.2 Transformer Installations A. Transformers will be installed to conform to the requirements of NFPA 850 and NEC 450. B. Mineral oil filled transformers shall only be installed outdoors. In general, such installations include the confinement of escaping oil by dikes, curbs or basins; and isolation from adjacent structures/equipment by distance or firewalls. Firewalls shall be constructed for a two (2) hour rating (cinder block or steel re-enforced concrete). Confinement areas shall be filled with crushed rock. C. All underground distribution systems shall install natural ester, vegetable oil transformers. Such insulating oils shall have a flash point not less than 300°C and shall comply with NEC (2008) article 450.23 (A) for indoor installations including the requirement for liquid confinement. Other vegetable oil transformer installations shall comply with other appropriate NEC articles. D. Dry type transformers shall only be installed indoors except for completely enclosed pad-mount types rated for outdoor installations. E. General a. This Specification covers liquid-immersed and dry-type transformers. The Vendor shall apply the appropriate Technical Requirements of this Section, as required by the type of transformer specified on the Data Sheets. b. Windings shall be electrical grade aluminum unless noted otherwise on the Data sheet. (Note: Bushings for oil-immersed transformer shall be equipped with silver-plated copper spades. For dry type transformers the bus connections for external cables shall be silver-plated copper bus.) c. All bushings shall be fully insulated (i.e., BIL rated accordance with standard BIL levels). Bushing BIL shall also be adjusted for air correction factor per ANSI C57 and ANSI C37 when required d. The transformer shall be designed, manufactured, and tested in accordance with the applicable NEMA, ANSI, and IEEE standards