Fill in the blank with the appropriate answer.
For field-fabricated installations using equipment operating at more than 600V, the minimum air separation between live conductors and between such conductors and adjacent grounded surfaces shall be a minimum of______ in. for an indoor, phase-to-phase application of 13.8kV.
Section 490.24 of the 2011 NEC lists the requirements for the minimum air separation of field-fabricated installations. The minimum clearance distances are shown in Table 490.24.
Note: The values from Table 490.24 do not apply to interior portions or external terminals of equipment designed, manufactured, and tested in accordance with accepted national standards.
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