"The circuit breaker is good and occasionally I'll get a reading of 120v on both..." You need to be aware of the shrotcomongs of the differnt meter & measuring devices. Digital meters put such a small load on the circuit they are prone to 'phantom' voltages. The 'non-cpmtact' type probes (light sup when voltage near) are also prone to this. Zolder analaog meters are generally the most reliable, though they often lack the bells and whistles of nwere digital meters. One thing that often works well is to place a load from a light bulb on the circuit, THEN measure. The bulb provides a low enough impedance that phantom voltages are 'bled off' and will no longer affect the reading.

The reviews on Amazon don't give me that warm fuzzy feeling. :) There's only 6 reviews and half of them are bad. That is, if you read the actual review. There are a couple of 4 stars that don't sound like they should be 4 stars if you read the comment. Now that it actually exists, I wonder how many people are willing to spend 30 bucks plus shipping for it. As a side note, this thread seems like one that lots of people feel the need to sign up for a Houzz account, make one comment on this thread pointing everyone at SwitchFlip and then not participating in any other discussions. Is it possible that these people have an ulterior motive in promoting this product? :)

I've seen this alot recently in the last few years. Code requires separate circuits for washers and dryers, but several older homes have just one outlet back there that serviced an old-style top-load washer (which relied on an external hot water tank for warm or hot water) and a gas dryer, which used 120V/15A power to spin the drum, blow the fan, and run the electronics. Both of these worked fine sharing a single circuit. But now, people are buying internally-heated front-load washers that draw in a small amount of water (usually cold water no matter how the controls are set, since it's long cooled down in the residual pipes leading from the water heater tank). Then the internal water heater kicks in adding 1000 to 1300 watts to the load, plus whatever the washer needs to run the motor. Run a dryer off the same outlet at the same time, and the circuit overloads. I'd bet if the washer were set to tap-cold-water-only, with all the quick-speed, delecate fabrics, and low-soil options selected (so as not to have it turn on the heater), the washer and dryer would continue to coexist in peace on the same circuit. Doing this would hobble the washer's capabilities though, so a separate, dedicated 120V/20A line should still be installed for the washer.

Obviously you didn't use THWN wiring for wet locations. You should always check here first when selecting wiring....