The answer to 'what size electrical wiring do I need' is that the size of electrical wiring you need depends on the specific electrical load and application in your home. As a general rule, the larger the electrical load, the larger the wire size required to safely carry the current. Factors like the length of the wire run, the type of circuit (e.g. lighting, appliances, HVAC), and local electrical codes all play a role in determining the appropriate wire size.
For most standard household circuits, 14-gauge or 12-gauge wire is commonly used. Larger appliances like electric ovens, dryers, or air conditioners may require 10-gauge or even 8-gauge wire. It's important to carefully calculate the electrical load and select the proper wire size to ensure safe, efficient, and up-to-code electrical wiring in your home.