So this is a question that's been asked a lot, but reading individualized responses is creating confusion for me, not answers. I have a detached garage with existing power, and I have added a few items to the circuit. Because I don't know what the original design of the circuit was, I'd like to remove the additions and add my own dedicated circuits to operate what I need.
I will leave the 1/2 hp garage door opener, the single bare bulb light fixture (although I could remove this with no stress on me) and the two duplex receptacles on their original circuit.
I have only three empty slots in my main breaker box and will run 12/3 wire about 200 feet to my garage (unless suggested to do otherwise.)
What I'd like to power is:
6 four foot florescent light fixtures, two T8 bulbs each will be switching to LEDs as budget allows, on a switch near the entry door.
8 LED recessed lighting fixtures in the eaves of the garage, with one motion detecting flood light out front, dusk to dawn switched in the house and the garage.
- 8 receptacles that will be responsible for powering: 3 to 4 power tool rechargeable battery chargers that may or may not be used at the same time. a 7" power saw, a 12" miter saw, a 10" table saw and eventually a light to medium duty MIG welder (110 v) and a 2.5 hp air compressor with intermittent auto start, a bench grinder, a shop vac, and assorted hand tools, grinders/drills/soldering irons/routers etc.
The power tools (with the exception of the chargers) won't be used at the same time, I only have 2 hands. But I can envision using the big saw and having the compressor kick on. I obviously don't want to suddenly be working in the dark, or to burn my garage down.
What should I run from the main breaker box to the garage? Should I install a sub panel? What size breakers for each circuit? All three circuits now, or two with future expansion? How would you design the circuits to accomplish what I want to do?
I understand, ahead of time, that the absolute best way to do this would be to hire a reputable electrician, but I am a big time DIYer, and would like to learn as I go. I also understand that I am only asking for advice from experienced folks, and am still responsible for making my own decisions, and facing any potential consequences....
To be more specific, I have a GE 200 amp main box on the outside of my house, say street west side. The detached garage (attached by a breezeway roof overhang) is in the back yard east side. I stepped it off and being pretty liberal came up with a 167 foot run. The plan is (until advised otherwise) to run a conduit from the main box up to the attic, through the attic and the breezeway connector to the garage. My local code prohibits aluminum wire, so suddenly my small project just became a major expenditure and overhaul. The three empty slots in the main are randomly placed, I would have to relocate one double pole one position upwards to gain two adjacent slots for an additional double pole. I researched and simply muddied my own waters. Went looking for answers, and came back with more questions.
As you can see from this very, very rough sketch, burying the feeder wire is not an option. The solid black line between the two buildings represents the breezeway which connects the two, and through which the existing wire is run, down from the attic to the first story ceiling and through the connecting run. I priced some 2/2/2/4 for the feeder and holy COW, I think I need a copper mine of my own.
Anyway, those are the distance specs, with the same power tool toys as described above. Still--any suggestions?