BASIC NEC CODE RULES AND DESIGN PRACTICE

Next higher CB size is 90 Amp. NEC 240-6 and 240-3 exception 1, conduit-size, 3 #4 in conduit Table 3A = ... 60 6 48. 70 4 56. 80 4 64. 90 3 72. 100 3 80 ... Include ampacity and panel circuit space both. 50% is preferable. Voltage Drop. Check service entrance to panel and branch circuits run over 75-100 feet for voltage drop, this may increase ... ................
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