I have a DeVilbiss airpro, about 5.5 peak hp and supposedly 15 amps. But they lie...it takes a dedicated 20amp circuit to run these things. I suspect the Sears two stage 30 gallon is the same. I'm running a new line to the garage this week with 12-2 Romex and a GFCI. It's really irritating to have a new house and they put one of the outside light poles on the garage 15amp circuit....Heck, maybe I should run two single circuit 20amp lines and an 8-3 220v circuit at the same time. OTOH, a GFCI breaker costs over a hundred buckos but the 110 breakers about 30-60 (seriously check Home Depot for the QO breakers if you have a Square D panel) and you can cheap out with a std breaker and a 20amp GFCI in the wall plug. Another thing...the wall plug GFCI is easy to test/reset in the garage without having to walk all the way in/down tø the main breaker!

IMHO you need at least 135-140 psi and a 25 or more gallon tank to adequately operate an impact wrench (you can overpressure the stock 125psi settings on many compressors to get 140 but that's about it for the pump. The tanks are ASME tested to 300psi). It takes two stage compressor for 150-175 psi but the higher pressures really pay off in tool operation.