tyha
Senior Member
- Location
- central nc
we have a water heater with upper and lower elements that run do not run simultaneously. The unit is marked 3PH 4500W upper and 4500W lower. Doing the math it comes out to be about 12 1/2 or so amps which would be 3p 20A CB with #12 Thhn. Why am I thinking that is wrong and it needs to be #10. maybe because Im thinking of a single phase unit. Am I missing something or is it right?