Can I use a three-prong adaptor? June 30, 2023 02:08 Updated No, the unit must be earthed when running. Using an adaptor will result in the unit not having the intended safety features. Related articles My unit is dripping a lot of water outside. What should I do? Do I really need a three-prong outlet? Does the Gradient have an inverter, like some minisplits do? How wide can my windows be? What kind of climates is the Gradient good for?