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Unformatted text preview: APACITY. The provisions for transformer
vaults specified in Section 9.3 of this Rule apply except that the vault may be
constructed of reinforced concrete not less than 100 mm thick. 8.4.2 NOT OVER 600 VOLTS. A vault is not required provided suitable arrangements
are made where necessary to prevent a transformer oil fire igniting other materials,
and the total transformer capacity in one location does not exceed 10 KVA in a
section of the building classified as combustible, or 75 KVA where the
surrounding structure is classified as fire-resistant construction. 8.4.3 FURNACE TRANSFORMERS. Electric furnace transformers of a total rating
not exceeding 75 KVA may be installed without a vault in a building or room of
fire-resistant construction provided suitable arrangements are made to prevent a
transformer oil fire spreading to other combustible material. 8.4.4 DETACHED BUILDING. Transformers may be installed in a building which
does not conform with the provisions specified in this Code for transformer vault,
provided neither the building nor its contents present fire hazard to any other
building or property, and provided the building is used only in supplying electric
service and the interior is accessible only to qualified persons. 8.5 Guarding. Transformers shall be guarded as follows:
8.5.1 MECHANICAL PROTECTION. Appropriate provisions shall be made to
minimize the possibility of damage to transformers from external causes where
the transformers are located exposed to physical damage.
8.5.2 CASE OR ENCLOSURE. Dry-Type transformers shall be provided with a noncombustible moisture resistant case or enclosure which will provide reasonable
protection against accidental insertion of foreign objects. 8.5.3 EXPOSED LIVE PARTS. The transformer installation shall conform with the
provisions for guarding of live parts in PEC Rule 1056. 8.5.4 VOLTAGE WARNING. The operating voltage of exposed live parts of
transformer installations shall be indicated by signs or visible markings on the
equipment or structures. 9. Provisions for Transformers Vaults
9.1 New Building. New buildings requiring an expected load demand of 200 KVA or above
shall be provided with a transformer vault, except that transformers may be mounted on
poles or structures within the property if enough space is available, provided that all clearances required can be obtained and no troublesome contamination on insulators,
bushings, etc. can cause hazards and malfunctioning of the equipment.
9.2 Location. Transformer and transformer vaults shall be readily accessible to qualified
personnel for inspection and maintenance. Vaults shall be located where they can be
ventilated to the outside air without using flues or ducts wherever such an arrangement is
practicable. 9.3 Walls, Roof and Floor. The walls and roofs of vaults shall consist of reinforced
concrete not less than 150 mm thick, masonry or brick not less than 200 mm thick, or 300
mm load bearing hollow concrete blocks. the inside wall and roof...
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This note was uploaded on 09/22/2013 for the course ARIDBE AR taught by Professor Any during the Fall '12 term at Mapúa Institute of Technology.
- Fall '12