I designed a PCB which matches the dimensions of a receptacle box (the blue ones, just gonna call it the box). It is meant to mount next to an outlet in a double gang box and has a relay controlled by an esp to control the outlets. The components face into the box, and an led faces out, but is flush with the out-side of the board. I'm wondering the legality (code-wise) of installing a custom device like this into an electrical box. All it's doing is breaking or making the live connection to the outlet, but for now the design necessitates soldering the Live wire directly to the board, which I'm pretty sure I don't wanna do. If it had proper screw terminals for Live would that be ok? I'm having trouble finding information on this, maybe my Google-fu is off.
Wiring – Custom device mounted in electrical receptacle box
code-compliancewiring
Related Solutions
Equipment grounding wires have been omitted for clarity. Don't forget to properly connect all equipment grounding wires.
- Connect the white (grounded, neutral) wire from the feeder to the silver screw on the Line side of the GFCI receptacle.
- Connect the black (ungrounded, hot) wire from the feeder to the brass screw on the Line side of the GFCI receptacle.
- Connect the white (grounded, neutral) wire from the cable feeding the combo device to the silver screw on the Load side of the GFCI receptacle.
- Connect the black (ungrounded, hot) wire from the cable feeding the combo device to the brass screw on the Load side of the GFCI receptacle.
- Connect the white (grounded, neutral) wire from the GFCI receptacle to the silver screw on the combo device.
- Connect the black (ungrounded, hot) wire from the GFCI receptacle to the black screw on the switch half of the combo device.
- Break the tab between the terminals on the combo device.
- Connect a jumper (red) from the brass (switched) screw of the combo device to the black screw on the receptacle half of the combo device.
- Place a "GFCI Protected outlet" sticker on the combo device, and all downstream protected outlets.
With this setup the receptacle on the combo device will be controlled by the switch on the combo device, and will also be GFCI protected. In the drawing above, I've also included a pass through GFCI protected feeder. This pass through can be used to power, and protect down stream devices.
You should be able install a receptacle inside the cabinet, I'm not aware of any code that says otherwise, and the code you quoted describes the minimum requirements. It's often done for garbage disposals, dishwashers, and over the range microwaves. Using an extender ring is probably the easiest way, so you don't need to predict exactly how far the outlet box needs to be installed from the wall. With some cabinet installs, it may be so far out you wouldn't have a proper nailing surface for the outlet to the stud.
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Best Answer
That would not be code-compliant. The NEC requires that all installed equipment be listed by a recognized testing laboratory (i.e. Underwriters' Laboratories, "UL", in the US) who has performed safety testing.
One way to deal with this is to outsource the switching job to a listed relay that mounts in or to a junction box, so that the mains voltage is completely contained in the junction box. Outside, the relay gives you terminals (for either closing a circuit or providing a voltage) to control the relay. Your custom IoT gadget can control the mains circuit without needing to be listed itself, because it is isolated from the mains power.
Random example relay