This paper investigates wind loads acting on a nacelle with wind tunnel testing to address potential safety issues during wind turbine installation. When installing a nacelle using a crane mounted on a wind turbine tower, the proximity of the tower to the heavy nacelle can lead to a potential collision with the tower due to wind loads. Nine potential configurations during the nacelle installation process were tested. The drag and torque acting on the nacelle were experimentally measured for wind directions ranging from 0 to 180 degrees. The largest drag and torque were observed when the nacelle was positioned directly above the tower. Drag was maximum at 90 degrees to the wind direction, and torque was maximum at 60 degrees to the wind direction. When the nacelle was positioned behind the tower, the wind effect was minimal. The most dangerous situation was determined to be the moment when the nacelle was positioned directly over the tower, where the torque had the largest effect.