The answer to 'how much is junction box upgrade' is that the cost can vary significantly depending on several factors. Junction box upgrades typically range from a few hundred dollars to over a thousand, depending on the scope of work required.
The main factors that influence the cost include the size and complexity of the junction box, the accessibility of the location, the need for any electrical panel or wiring upgrades, and the labor rates in your local area. Larger or more complex junction boxes, as well as those located in hard-to-reach areas, will generally cost more. Additionally, if the upgrade requires updating the main electrical panel or rewiring parts of the home, the overall cost can increase substantially.