Question 10.3: What is the maximum ampacity of a 4 AWG copper conductor wit......

Determine the ampacity of a 4 AWG copper conductor with Type THWN insulation from the wire table. Type THWN insulation is located in the second column of Table 310.16. The table lists an ampacity of 85 A for this conductor. Follow the second column down to the correction factor chart. Locate 43° C in the far left-hand column of the correction factor chart; 43° C falls between 41° and 45°. The chart lists a correction factor of 0.82. The ampacity of the conductor in the above wire table is to be multiplied by the correction factor.

85 \mathrm{~A} \times 0.82=69.7 \mathrm{~A}