The answer to 'what size outlet installation do I need' is that the size of the electrical outlet you need will depend on the specific electrical load and requirements of the appliance or device you are powering. In most standard residential applications, a 120-volt, 15-amp or 20-amp outlet will be sufficient for most common household electronics, lighting, and small appliances.
However, larger appliances like electric stoves, ovens, dryers, or air conditioners may require a higher-amperage outlet, such as a 240-volt, 30-amp or 50-amp outlet. It's important to consult the manufacturer's specifications for the appliance or device you plan to use and ensure the outlet can safely handle the electrical load.