I have a customer requesting a price to hook up a tankless water heater. I know a service upgrade would be involved so I told him to get me the specs on the unit before I submitted a bid.
He called back and said the unit is 28.5 KW ! At first I thought he was mistaken on the load but after doing some searching I found that they actually draw that much for a whole house unit.
My question is, I don't see where the code actually adresses this type of unit, so what is the normal way to figure this into your service feeder calc ?
I see if I use the optional method I can put it in as the water heater load but would hardly make sense since it is almost 3 times larger than the central heat of the next step in 220.82 (c)
Any ideas or suggestions from people who have installed these would really help
