Derate 3 Conductors in a Raceway by Brandy McNeilin Electrical TablesFebruary 13, 2017 Number of Conductors in a Raceway Percent of Total Value 4 thru 6 80 7 thru 9 70 10 thru 20 50 21 thru 30 45 31 thru 40 40 41 and above 35