Building a new shop

Most electrical and plumbing decisions come down to personal preference and needs. You need at least a 100 amp service. Sit down with a clean sheet of paper and divide it in two, put the electrical tools that you own now on one side and then put the tools that you want on the other side. Write down the amps or max draw of each of the tools. Yes, a welder (mig or arc) is a tool! Add up and total your needs and multiply by TWO (because we know you're going to get more), and that's what service you'll need. Allow at least five outlets per 15 amp circuit. Don't forget that outlets in a garage need to be protected by either GFCI (ground fault circuit interrupter) breakers or GFCI outlets.  If you protect the first of the outlet boxes in a circuit with a GFCI outlet, all the rest of the outlets will be protected too.  A compressor or 220V mig will eat up 30 - 40 amps. "Brown outs", lack of correct power will fry a motor over time. If that shop of yours is getting a regular workout, maybe you should go with a new 'drop' instead of drawing off the house circuit.

Most electrical and plumbing decisions come down to personal preference and needs. You need at least a 100 amp service. Sit down with a clean sheet of paper and divide it in two, put the electrical tools that you own now on one side and then put the tools that you want on the other side. Write down the amps or max draw of each of the tools. Yes, a welder (mig or arc) is a tool! Add up and total your needs and multiply by TWO (because we know you're going to get more), and that's what service you'll need. Allow at least five outlets per 15 amp circuit. Don't forget that outlets in a garage need to be protected by either GFCI (ground fault circuit interrupter) breakers or GFCI outlets.  If you protect the first of the outlet boxes in a circuit with a GFCI outlet, all the rest of the outlets will be protected too.  A compressor or 220V mig will eat up 30 - 40 amps. "Brown outs", lack of correct power will fry a motor over time. If that shop of yours is getting a regular workout, maybe you should go with a new 'drop' instead of drawing off the house circuit.

Consider running all your wires in metal conduit surface mounted on the interior walls.  If you get your shop all wired up and the wires are buried in the walls, it will be a big deal to change anything later.  I used OSB (oriented strand board) for the walls in my shop, so I can attach electrical boxes anywhere without worrying where the studs are.  Bending metal conduit is simple once you get the hang of it.

Consider running all your wires in metal conduit surface mounted on the interior walls.  If you get your shop all wired up and the wires are buried in the walls, it will be a big deal to change anything later.  I used OSB (oriented strand board) for the walls in my shop, so I can attach electrical boxes anywhere without worrying where the studs are.  Bending metal conduit is simple once you get the hang of it.