2019 Electrical Wiring Costs | Installation Prices for Depending on your needs, your detached garage can be supplied by a single- or multi-wire circuit. For basic needs, a single-wire circuit can be run to accommodate both lights and receptacles. For higher electrical loads or in instances where lighting and receptacles need to be separate, a multi-wire circuit ( $1,200 to $2,500 ) can be installed How Much Does a Detached Garage Cost? - The Complete Guide Gravel driveway prices for a detached garage project can differ greatly based on gravel size and color and the type of substrate used. Estimates for average gravel driveway costs range from $1 to $2/sq. ft. although it can cost around $3/sq. ft. on the upper end.