Building codes usually limit the current carried by a no. 14 copper wire to 15 a. many household circuits are wired with this size wire. what is the drift velocity of the electrons in this case? the diameter of this wire is 1.6 mm. assume one conduction electron per atom in copper. the atomic weight of copper is 63.3 g/mol and its density is 8900 kg/m3. avogadro's number is 6.022 × 1023 molecules/mol and e = 1.60 × 10-19 c.