so I was wondering I have (6) 20 amp single pole circuits I’m trying to run in one conduit. If I upsize my wire to #10 can put all 6 circuits in that 1 inch emt pipe ? When I Derate I go to the derating adjustments go under 10 to 20 and see multiplier is .50 .... 75 degree Column for #10 is 35 amps which means I get 17.5 amps derating but that’s where I get confused


Staff member
New Jersey
Journeyman Electrician
What is the insulation type of the conductors you are using? If they're a 90° C conductor like THHN then you can use the 90° C ampacity for your derating calculation. #10 THHN = 40 amps, 40 amps * 50% = 20 amps after derating.