Optional Method Calculations with instant water heater

Cartoon1

Senior Member
Location
Florida
Occupation
Electrical Engineer
Regarding using the optional method load calculation. Using a tankless instant water heater: We can still put it into the rest of the loads and then taking 40% after 10kva load correct? for Nec2020



Thank you,
 
Yes, you can include it in the general load and apply 40% after 10kVA per 220.82(B) — unless your local code overrides or the heater's load is unusually high. Double-check with your AHJ when dealing with large tankless units — you may need to break it out separately.
 
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