Typically, a permanently installed hot tub is powered by a 240 V / 32 A (40 A breaker is also common) circuit, while some smaller “plug-and-play” models operate on 120 V / 15-16 A circuits. Even the 120 V models can run very close to the maximum rating of a standard smart plug for extended periods. Hot tubs are considered continuous high-load appliances because they can run heaters and pumps for long durations. Therefore, a standard outdoor smart plug is generally not an appropriate or recommended solution. Minoston MP22ZP Z-Wave 800 Series | Outdoor/Indoor Energy Monitor Plug