The JuiceBox Pro40 models are rated to work with both single phase (~120V US, 240V EU) and two phase (240V US). For both of these applications, the hot/live wire is tied to L1 on our relay. The neutral/common is tied to the L2 of the relay, and the ground/earth is to the same.
For the single phase, US 120V operation, the output amperage is limited to 12A, or 1.4kWs. When wiring an adapter to use for 120V operation, please use this wiring diagram. Our NEMA 14-50 to 5-15 adapters will work, as they are wired to work with our JuiceBox, specifically. Standard adapters that you buy elsewhere will not work.