Hwt amps

Ok I have a 284 Litre (75 Gallon) HWT tank on a 240V 20 AMP breaker. The hot water heater states 3800/4500W upper and 3800/4500W Lower with 4500W Max Load. It is a GSW.

OHMS LAW comes up with 18.75 AMPS

This needs a 30 AMP breaker right?

Right and 10 gauge wiring!

The load is as you’ve stated 4500 watts:

4500w/240v=18.75 amps

The NEC considers a HWH a continuous load therefore the circuit must be sized at 125% of the nameplate value:

18.75 amps * 125% = 23.4 amps.

This could be on a 25 amp OCPD with #10 AWG conductors.


Correct but 25 Amps breakers are not common so the 30 Amps are used.

That is true, but 25 amps is considered a standard size OCPD by the NEC.

I just wanted to point out that using a 25 amp OCPD in this application would be code compliant and that a 30 amp is not required.