All questions and answers are based on the 2014 NEC.
Q. How do we size the conductors and maximum overcurrent protection for an electric water heater? Please give an example.
A. An electric water heater having a capacity of 120 gal or less is considered a continuous load, for the purpose of sizing branch circuits [422.13]. Branch circuit conductors must have a rating of at least 125% of the ampere rating of a continuous load