For eight 12 AWG THW copper conductors in the same EMT, what is the minimum EMT size required?

To determine the minimum size of Electrical Metallic Tubing (EMT) required for eight 12 AWG THW copper conductors, it's essential to calculate the total fill of the conductors based on the NEC (National Electrical Code) guidelines. The NEC provides specific guidelines regarding conduit fill that ensure conductors can be installed without overheating and that they have sufficient space for bending and pulling.

For 12 AWG THW conductors, the allowable fill for each conductor is 0.0133 square inches. Since there are eight conductors, the total fill area would be calculated as follows:

Total fill area = Number of conductors x Area of each conductor

= 8 conductors x 0.0133 sq in = 0.1064 sq in.

Next, the NEC specifies that the cross-sectional area of the EMT has to be larger than the calculated fill area. Thus, you consult the NEC conduit fill tables, which outline the allowable fill for different conduit sizes.

After examining the tables, a 3/4" EMT has a cross-sectional area that comfortably exceeds the total fill of 0.1064 square inches, accommodating the eight 12 AWG conductors effectively. A 1/2" EMT, on