CautiousDIY
New User
- Location
- USA
- Occupation
- Engineer
Full disclosure - I am NOT an electrician and don't claim to be. Have done a lot of small electrical jobs but this one is a bit different. I want to install a 1400 watt under-sink hot water heater (HWH). It uses a simple 3 pronged plug and I can easily install an outlet box under the sink and tap into one of two existing 120v circuits for the power. Both are in a gangbox above the counter, so it's pretty easy to pull 12 gauge Romex straight down the stud to the opening under the sink. I have a 20 amp circuit that feeds multiple outlets including the ones used by the fridge, toaster oven, and coffee maker. My concern there is that the HWH at full draw will likely trip the breaker when toaster oven is running or the fridge kicks in. I can deal with the toaster oven turning off, but I don't want to lose a fridge full of food if this trips in the middle of the night or while we're away.
The other is the dedicated 15 amp circuit for the garbage disposal, which draws 8 amps, so it can't be on at the same time the HWH kicks in. However, you're never needing hot water while you're running the disposal, it's an either-or thing. (I'll also install a separate switch on the outlet for the HWH so it can just be shut off manually.) What I;'m wondering is can I use a 15 amp capacity 3 way switch to effectively have the HWH on when the disposal is off, and when you turn the disposal on, the HWH is powered off? I'm pretty sure that this would actually work from a technical perspective - the HWH and disposal can share the neutral and the hot will be controlled by the switch. The question is, would it be to code, is it even a good idea?
The other is the dedicated 15 amp circuit for the garbage disposal, which draws 8 amps, so it can't be on at the same time the HWH kicks in. However, you're never needing hot water while you're running the disposal, it's an either-or thing. (I'll also install a separate switch on the outlet for the HWH so it can just be shut off manually.) What I;'m wondering is can I use a 15 amp capacity 3 way switch to effectively have the HWH on when the disposal is off, and when you turn the disposal on, the HWH is powered off? I'm pretty sure that this would actually work from a technical perspective - the HWH and disposal can share the neutral and the hot will be controlled by the switch. The question is, would it be to code, is it even a good idea?
