Water heater breaker sizing

[hhsting]

I have 2kw storage type water heater, 277V single phase and branch circuit breaker provided is 20A. Quoted 422.13 and said should be 15A but was told 20A breaker is okay since #12 AWG wire is provided.

Questions:

1. Where is the above mention that makes 20A breaker okay in NEC 2014 section 422 or elsewhere?

2. Should the breaker be 15A or 20A and what code section?

 

[Dennis Alwon]

Look at 422.11(E). I didn't check the math

 

[bwat]

Check to see if you think 422.11(E)(2) applies.

(I see Dennis beat me.. load is 7.22A so I think it applies)

 

[Dennis Alwon]

Looks like 20 amp is good since it is not rated at more than 13.3 amps

 

[tortuga]

422.11(E)(1) is poorly worded as the appliances are only marked with a wattage. You have to look up the water heater in a table in the instructions, which often are discarded by the plumber. 110.3(B) The manufacturers instructions usually spec a 15A for 3kw or less @ 277.