My wife has a fish tank in the living room. It requires continuous power for the pump/filter, and automatically controlled power for lights and a CO2 solenoid. Since water is nearby I'll be putting it on a GFCI circuit. My wife would also like to flip a switch to override the automatic schedule and turn on the lights; same for the CO2.
We currently have everything on an extension cord and a mechanical timer. I plan to replace that with a custom WiFi-enabled electronic gizmo and some proper receptacles.
Is the following an okay plan?
Mounted in three gang wall box behind the fish tank:
- One duplex GFCI outlet (two receptacles). This will provide GFCI protection to everything as well as two always-on receptacles. 15A receptacles (20A feed through). Tamper resistant. LEVITON GFTR1-W
- One duplex outlet (two receptacles) marked "controlled" on both receptacles. Hot tab broken. One will be for lights; the other for CO2 solenoid. 15A. Tamper resistant. LEVITON TBR15-S2W
- One duplex combination toggle switch (two switches in one gang); both will be three-way. Each switch will switch one "controlled" receptacle between automatic control and always-on. 20A. LEVITON 5640-W
I'll tap into the existing outlet circuit in the room. Hand-wavy control circuitry will be mounted in the crawlspace below the floor.
Am I allowed to use three-way switches like this?
I know I'll need 12AWG wire. Will I need $$$ 12/4 (with ground) wiring to/from the control circuitry, or can I do that with two runs of 12/2 (with ground)?
As stated above I'm imagining the receptacles and switches (image above) living in an old work box in the interior wall behind the fish tank, and fishing wires through the wall down to some kind of enclosure between the floor joists where the control circuitry will be hardwired in.
The crawlspace below this floor is 5+ feet high, unfinished, and you access it by opening a trap door in a closet and climbing down a portable ladder that's usually there. I'll ask my AHJ, but I bet the control circuitry will be considered "accessible" since it doesn't require modifying the structure or removing drywall or anything like that, and also because there are already outlets (in the NEC sense of the word) down there (for well pump, sump pumps, water softener, etc).
We live in Michigan, USA. This is the other half to this question.