BASIC NEC CODE RULES AND DESIGN PRACTICE

If more than 3 phase wires are in one conduit, then wires must be derated according to Note 8, after Table 310-19 as follows: TABLE 1. Number of Conductors Percent of Values in 310-16 *1-3 80 *4-6 80. 70 25-42 60. 43 and above 50 *If circuit is loaded up to 80% ampacity, then 6 phase wires can be put in one conduit. ................
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