When i moved in to my house, the shop (12 by 40 metal building) was set up for wood working. It was only wired with some plugs run from the main panel of the house. I paid an electrician to upgrade from 100 amp to 200 amp panel and run a 100 amp sub panel to the shop. I worked it out with the electrician to do the manual work myself (concrete cutting and digging for the conduit), and he gave me a price off $1500 to do everything else. I thought it was well worth it. I cut concrete from the main panel to the shop, excavated the ditch, and when they were finished i buried and poured concrete to match existing. They installed the new panel, brought everything up to code, and installed my welder plug, and some extra plugs. Now i have enough power to run my welders and plasma cutter, and my big compressor. I have to change plugs for the welders and such, but i am glad i did it right in the first place. It is super nice to be able to run what i want in the shop with out having to unplug appliances in the house!