BASIC NEC CODE RULES AND DESIGN PRACTICE

1. After circuits have been derated to get proper wire size use Table 3A if wires are all same size. Use Page 70-57"9, or Tables 4 and 5 if wires are all different size. Ground wires should be run with all branch circuits. Example: Load Furnace 15 KW, I phase, 230V, find current, KVA, wire size, circuit breaker size, conduit size. ................
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