Ok...
I too would like to put a grow in a building located on my property but not in the house...
Here's what I've been thinking (please correct me if I'm wrong.)
I currently have a 220 line run out to the middle of my yard where the previous owner had an above ground pool.
What I was thinking is this.
Remove the 220 line completely (breaker wire and all) from the yard and leave the conduit in place extending it to my building.
Install a 150 AMP breaker in my main house box and run 200AMP rated wire through the old and new conduit to my building where I install a sub panel.
I want at least 3 dedicated 20 amp breakers for HID lights and an AC/Dehumidifier, nothing on these but timers and HID lights and the AC.
Then I want around 15 - 20 outlets for air and water pumps, CFL lights, Floro Lights, and fans.
I believe that 150Amp should cover the whole thing I've read that 1000watt HID's pull about 15 amps so a single 20 amp breaker per light should cover it.
I will get 40amp wire for the HID's and AC, just to be safe.
So what I have is a total of 60 amps for HID and AC.
Then set of 4, 20 amp breakers for 'sundries' that don't pull near the amperage. That would leave my main breaker 10 more amps than I intend to breaker for in the sub panel, plus 5 extra amps each on the HID and AC, and then 4 series of 20 am plugs that would fall under 'standard house.' So a total of 125 amps used with 25 'not used' for potential overloads.
Thoughts?
-RT76