Wire the Circuit Panel and Finish Installation
With the switches and fixtures correctly wired, it's time to wire the main circuit panel. After stripping the incoming cable, connect the neutral and ground wires to their corresponding bus bars. To finish the circuit, connect the hot wire to a circuit breaker, which itself is connected to the panel's hot bus.
Using a volt-ohm meter set to ohms, touch the probes to the various busses on the panel, and then change the position of the three-way switches for another reading. A slight energy reading indicates the circuit is sound.
Screw in the light bulb and plug in the exhaust fan. Flip the main breaker to energize the panel. Before flipping the branch circuit breaker, verify the current using the meter, this time set to volts. With the reading well within perimeters, it's safe to flip on the branch circuit.