A water heater of this type is required to be considered a continuous load meaning that the branch circuit needs to be calculated at 125% of the heater's rated ampacity.
4500/240 =
18.75 amps, will work on a
20 amp OCPD but, 18.75*125% = 23.4 amps, requires a
25 or
30 amp circuit.Oct 2, 2012
read more >>