Install IoTaWatt to meet U.S. / MN electrical code?

We’re in a new house and getting some static about the IoTaWatts and IEC. My understanding was that I could have a separate box (6x6 plastic) with conduits to the breaker panels. The IoTaWatts could be mounted to the cover plate of the box with sensor wires routed through holes in the cover plate and then through conduit to the panels.

I could put them inside the 6x6 boxes but am concerned about WiFi signals and there would still need to be a hole for the PS and Voltage sensor.

How have others done these to meet code and satisfy picky electrical contractors and inspectors?


You didn’t say what the specific objections were, so I can’t respond to that.

My go to enclosure is an indoor/outdoor enclosure made by Orbit for sprinkler controllers. If you search the forum for “Orbit” you will see a few installs. What I like about this box:

Big enough for IoTaWatt, VT and USB and connections.
Has mounting plate inside to screw IoTaWatt to.
Has a UL duplex GFCI inside for the USB power and VT.
Has a lock
Seems to pass the WiFi OK.

You mention multiple IoTaWatt. There is an example of a dual setup here.

The Accu CTs are UR, the VT and USB power are UL, the IoTaWatt is certified to applicable standards by ETL.

Thanks @overeasy. That link was quite helpful.

We’ll likely have 3 or 4 IoTaWatts when all is said and done (currently have one). We have one main 600A meter base that feeds two 200A panels + three sub panels in our house and one 200A panel in our studio. Also a 200A time-of-use meter base that feeds one 200A panel in house and one 200A panel in studio. Also a solar array that feeds one of the 200A panels in the house.

Panels are all flush mounted in sheetrock walls so I assume to do this right I’ll need to pull a bunch of sheetrock, install conduits + boxes, re rock the walls?

Again, I don’t know what the code objections are.

I get that you can’t put the IoTaWatt inside the electrical panel, but beyond that what is the concern? In the past, some jurisdictions had issue with any “foreign” systems in a panelboard, and you would need to have a second box above or below the panelboard where you install all the CTs, but that is rare today (unless your panel is extremely full and the CTs do make it look “unworkmanlike”).

The sprinkler enclosure is a great idea; wish I had found that sooner. (I would replace the outlet with a combination plug and USB port.) Mine are just wall mounted above the panel with a duplex outlet, and I have a “mouse hole” between the panel and the IoTaWatt.

While the USB port will work, they are designed for charging. A USB power supply is designed to deliver higher quality power, specifically with low ripple, which the ESP8266 power regulation doesn’t handle excessively well. A decent USB supply is probably less than a USB receptacle and the Orbit has GFCI. The VT and USB seem to fit together in the Orbit box.

Good points, thanks!