Yes, turntables and pallet carousels can be used outdoors, but several factors must be considered to ensure their effective and safe operation. Firstly, the materials used in their construction should be weather-resistant to withstand elements such as rain, snow, and UV radiation. Stainless steel or galvanized steel are often preferred for their corrosion-resistant properties. 
Secondly, the electrical components, if any, should be adequately protected against moisture and dust, often requiring an IP (Ingress Protection) rating suitable for outdoor use. This ensures that the motors and control systems remain functional in adverse weather conditions.
Thirdly, the surface on which the turntable or carousel is installed must be stable and level to prevent operational issues. Outdoor environments can be uneven, so proper site preparation is crucial.
Additionally, consider the load capacity and ensure it matches the intended use, as outdoor conditions might impose additional stress on the equipment. Regular maintenance checks are also essential to address any wear and tear caused by environmental exposure.
Finally, safety measures such as non-slip surfaces and appropriate signage should be implemented to prevent accidents, especially in wet or icy conditions. 
In summary, while turntables and pallet carousels can be used outdoors, careful consideration of materials, protection of electrical components, site preparation, load capacity, maintenance, and safety measures are essential for their successful deployment.