In the majority of cases, when upgrading to an electric panel with 400 amp (and in certain cases, a 200-amp panel), you’ll also require an additional subpanel or two. The cost of these subpanels ranges between $500 to $1000.

An electrician must have a state license to operate in California. A C-10 Electrical Contractor license is issued by the Department of Consumer Affairs, Contractors State License Board.