I decided to stop by Home Depot on my way home and pick up a Vol Test XL. I could not get a reading off of the 250V Hart Lock. Because I did not get a reading does this mean that the line is dead? I did find out that I have 120 V running to the garage and another 110 V running to the spare bedroom behind the garage. I also found out a little more info on the hart lock...easier to investigate in day light. It is made by Arrow Hart Inc., Model Hart Lock 50A 125/250 V; CAT NOS: CS6364. (Refer to link at bottom) You also mentioned to me that I should not turn this on... would I have to flip the breaker to turn this on or is there another method to power it up. All the breakers in the electrical box have always been on. I don't want to mess with it to much cause I don't know if it is live or not. I was also able to get information off of the wire, the underside is not painted. The writing on the wire read; 12 3 TYPE SO 90 G P 123 70 MSHA. If this wire is live would I be able to, or have an electrician, run the conduit another 25 ft, set up a breaker box, and run all my equipment off of two 120 V breakers. For the run all I would have to do is extend the line up the exterior wall, core a hole through the attic crawl/space, run the line over a den, and it would be in the garage. The den was an add on so the attic/crawl space in the den is exposed in the garage. I would love to take advantage of this if I can, but I know how delicate of matter electricity is. I would not want to hook anything up that wasn't solid. Let me know what you think.
http://solutions.cooperwiringdevices.com/common/brands.cfm?pg=Detail&brandName=CWD Industrial&category=Locking Devices - Hart-Lock®: 50A: Connectors&id=17571
It's hard to see where the wire goes but it looks like it's going underground and that wire is not rated to be burried it looks larger than a 12-3 but it doesn't really matter I would turn it off and take a walk around testing things to see what isn't working if it's going underground it might be coming up anywhere.
The one thing I would do is to have an electrician come out and look at it and move on from there the electrician might be able to run a new circuit to power your equiptment if it were me I would run an extra circuit just in case you decide to go with some heavy lighting I don't know how many plants your planning to grow and don't know if your going to have two seperate areas one for grow and one for bloom but if you do it would make sense to have some extra juice some of the guys on here go a little overboard on lighting but if you go with High intensity discharge lighting (HPS or MH) they draw more and make the room very hot so you'll have to plan for cooling it off there's lots of threads on here to help you decide how to set up your room.
If your going to grow just a couple of plants one or two plants, CFL's run cool and don't pull alot of power but I don't want to influence you on your lighting choice.
That said you seem level headed and know your not experienced with wiring there's some really nice hydro setups out there that you can use in fact there are kits available that you can grow 6 plants in from start to finish that are very reasonable they even come with the nutrients and lights there is a thread that Roseman has just started on his latest closet grow using one of these kits.It's set up for the beginner it will tell you how to set up the system and where to get it, but don't try to post on that thread he wants to keep it clean so its easy to read for people new to growing he says from start to finish it takes 90 days give or take to harvest he has grown using this method many times and swears by it.
Also if you read it carefully ther is a coupon code for either a 10% or 20% discount from the hydro store, the kits go for around $200.00 and up depending on what options you choose you just supply the water and the seeds or clones.
I'm not trying to sell you on anything but the system draws very little power and you might not have to have an electrician run a new line so in the long run its not a bad option in fact I looked up Rosemans grow for you to save you time here's the link:
https://www.rollitup.org/dwc-bubbleponics/234626-rosemans-diy-bubbleponics-tutorial.html
Again I'm not trying to sell you anything but offer you an option.
If you prefer to grow in soil there are plenty of threads that you con read or if you are an experienced grower please disregard this part but have that old line looked at either way.
It's getting late and I'm beat.
Good luck what ever you do but have that looked at soon.
Thanks.