A tankless water heater I bought arrived with a pig tail with 3 6 AWG wires. Black, Red, and Yellow with Green stripe ground. The black and red go to a 2 pole 60 amp breaker with the yellow/green going to ground/common on a very old Cutler-Hammer breaker box.
I went to the local box store and they didn't have the 3 6 AWG wire but did have a two 6 AWG with a 12 AWG ground. I was told that it would work just fine with the Black 6 AWG, White 6 AWG and 12 AWG ground.
I connected everything and the heater works great. However, I'm concerned that the 12 AWG wire is a huge mistake and it might actually be a fire hazard and I should remove that wire and replace with a 3 6AWG wire.
Should I be concerned or not?
Thanks in advance.