Wiring a 3-Wire Dryer Outlet - Ask the Electrician Wiring a 3-Wire Dryer Outlet Help with Electrical Wiring for a 30 amp 3-wire Dryer Outlet: Make sure that the white wire is wrapped with black or red electrical tape at both ends of the cable to identify it as being a hot wire and not a neutral wire. Wiring Diagrams for Multiple Receptacle Outlets - Do-it Wiring Diagram for Dual Outlets. Here 3-wire cable is run from a double-pole circuit breaker providing an independent 120 volts to two sets of multiple outlets. The neutral wire from the circuit is shared by both sets. This wiring is commonly used in a 20 amp kitchen circuit where two appliance feeds are needed, such as for a refrigerator and a microwave in the same location.