I think the breaker can handle it with no problem. I was just looking at the breaker and it has a subpanel already leading off of it to control the laidnty room and garage and another panel in the laundry room. BUt they are pretty far from my grow room. Is there a way to hook these lights up without installing a subpanel. I really dont wanna go that rout unless i have to.
No it is not necessary, it would be for convenience or cost. You can run individual wiring from your main panel to a spot in the room and install receptacles. For this application you would only need to run 14 wire with 15 amp breakers, standard household out lets. When I did mine, I was saving money on the labor so I used 12 wire, 20 amp breakers and receptacles.
It sounds like they added subpanels as they added to the original house and upgraded the service entrance to a higher amperage, if the house has a basement and an attic its quite possible you have a blue print of how they did it all laid out there, just follow the big wires. The smaller wires that run out of your subpanels would be extension cords if the subpanel were not there and they had separete receptacles instead of a panel.
Most subpanels will operate off 4 wires, Black, red, white and green which gives you 220 power at the subpanel. The black wire and the red wire will be attached to the di-pole breaker switch, this switch would be a minimum of 30amp, for this application I would recommend 50 amp, which is the same breaker you would use for an electric stove. 40 amp is fairly normal for central air, and 30 amp is a normal electric dryer in my area. The white wire will go to the nuetral bar and the grounding wire will go to green grounding bar. The size of the wire will depend on your local codes, I think it could require as high as 6-3 wire with ground, if you went with the 50 amp.
If you wanted to have individual circuit instead, and if I were doing this for myself this is the way I would do it, you would deal with 3 wires instead of four, black, white, and green. The black wire will be attached to you single pole 20 amp breaker, the white and green wires will be attached at the same spots as they would have in the previous installation. When you put the breaker in place it makes contact with the bar down the center, and completes the circuit. You would run 12 wiring to where you want them for each plug you would install. The reason I would choose this is at resale time. Almost all rooms in our houses now are under powered for all of the electric items we have now, everyone has a power strip plugged in some where. Current code is a duplex for every six feet of wall in my area and I installed it that way in my family room. Still have a power stip behind the tv. They make boxes for retrofitting in an existing wall that work well, have special ears that hold them in place and meet code. And they have special $50.00 long drill bits for going thru plates, this could be fun. VV