Water heater overcurrent protection

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tcsh

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I hope that I am correct in reading code section 422.11.E. A water heater with 2-4500 watt heating elements is allowed to have 20 gauge wire and a 30 amp circuit breaker. Please let me know if I am incorrect. Thanks
 
Re: Water heater overcurrent protection

Will only one element at a time will run?

What voltage?

4500 / 240 = 18.75 amps x 1.25 = 23 amps.

12 AWG is rated 25 amps @ 75 C so it seems like you would be all set.

Your not, 240.4(D) will limit 12 AWG to a 20 amp overcurrent device for this application.

You can use a 25 or 30 amp breaker with 10 AWG or larger wire for this water heater.
 
Re: Water heater overcurrent protection

I believe the use of 12 gauge wire protected by a 30 amp breaker as you describe, would be a violation of 240.4(D). I don't see anything in 240.4(E) through (G) that would change this. 422.11(E) addresses the maximum overcurrent protection for the water heater, but it does not address the overcurrent protection for the supply circuit conductors.
 
Re: Water heater overcurrent protection

i just noticed the wording has changed since 96 nec.I am still correct that you can't use a 3o amp breaker but wrong on its rating .it is rated at 25 ocpd at 20
 
Re: Water heater overcurrent protection

Is'nt it true that article 422 part 2 of table 240.4[G] is exempt from 240.4D.??
 
Re: Water heater overcurrent protection

Yes, Motor-operated appliance circuit conductors in Article 422, Part II are exempt from 240.4(D) A water heater is not motor operated.
 
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