How many receptacle outlets must be installed above a show window?

The requirement for receptacle outlets above a show window is based on the need to provide adequate electrical service for displays and lighting. According to the National Electrical Code (NEC), specifically in Article 210, there should be at least one receptacle outlet installed for every 12 feet of show window length. This ensures that there is sufficient access to electrical power for the operation of lighting or other display elements, which enhances the display's visibility and attractiveness.

Receptacles placed every 12 feet allow for adequate flexibility in display arrangements, ensuring that lighting and other electrical devices can be utilized effectively across the length of the window. This spacing not only promotes safety by preventing the use of long extension cords but also helps maintain a tidy appearance for the display area.

The other options suggest different spacing that does not align with NEC requirements, emphasizing that careful adherence to the code is crucial in ensuring both functionality and safety of electrical installations in commercial settings.