As mentioned previously, the nature and scope of the electrical work will have a major bearing on how much it will cost to wire a garage or shed. For example, if the structure is detached from the main house, a main line will have to be run to the shed or garage before any interior wiring can be completed thus increasing the costs. Similarly, the number and type of outlets, switches, lights and appliances that are installed will also affect the price for better or worse. Generally, a small shed with nearby existing service will cost around $900 while a larger garage that needs to have a service “pulled’ to it and then to the home can cost as much as $4,000 to complete.