25 amp 2pole breaker for water heater?
Hello gardenweb, this is my first time posting on here so please bare with me.
I have an electric water heater that I need to connect.
The heater is 4500 watts 240 single phase
It requires an 84 foot from the sub panel.
The math I used looks like this.
4500w/240v = 18.7A
18.75A X 1.25(to maintain 80% of breaker capacity)= 23.4375Amp breaker minimum
Now according to the calculator on the below linked website I can use 10 awg copper and still be under 5% voltage drop.
Unfortunately nobody here in san francisco has a 2 pole 25A circuit breaker. If I bump up the breaker to 30A then I have to also bump up to an 8awg and that will cost me $90 which I don't really want to spend (and I don't want to snake 8-3mc through a wall for 84 feet). Is there a reason that nobody has 25A 2 pole breakers? I can find them online. I know they are made. I can't find any reasons as to why they are not existent. Are they illegal and I don't know it? Is there a reason for me not to use a 25A 2 pole breaker? This is in a commercial building which I don't believe makes a difference in this question.
Thanks for any advice on here..
(link to Voltage drop calculator that I used)