Note I am NOT an electrician or even very knowledgable in this field. Im just a geek who seeks answers and is sharing what I found and looking for confirmation. If there are any electricians reading this then confirmation from you would mean a lot. I have embarked upon creating a small-scale high-stealth grow room. I decided to use my crawl space which, thanks to a sloping lot, allows me to stand up. First order of business is to get me some power down there for everthing. I already have a furnace with power. I plan to tap into that circuit. This left me with some naggin questions as I was concerned about overloading the circuit. My quest was to find out how much power my furnace requires and the capacity of the circuit so I could rest knowing I'm not going to overload the circuit after I add grow equipment. It turns out that a typical 15 amp residential circuit can handle 1800 watts of power. I couldn't find the power requirements for my furnace but I did find out that a typical furnace draws about 800 watts. That leaves me and my grow room about 1000 watts for the good stuff. This is plenty for a small scale operation for personal use. For those with larger appetites you may have to seek other options
I am not an electrician either but I do my own wiring through my house; lots of reading. A 15 amp circuit can handle 1800 watts, but the safe load is 80% or 1440 watts. Overloading a circuit can be dangerous with certain electrical panels or just keep tripping your breaker. Your best bet would be to run a seperate circuit to supply your grow. It is easier than you would think to add a new circuit. If you really need someone else to do it, just ask an electrician if they would do a side job and add the new breaker to your panel and you can run the wire and receptacle setup. Good luck in your adventures!
I think it would be a good idea to see how much amperage you'll be pulling. Add up the amps your furnace and everything else you plan on putting on that particular circuit. . Dont exceed the rating on the wire either, most 15amp breakers are powering a circuit run with 14-2 AWG. I'm not sure what kind of a furnace it is, but if it's more than just a furnace(HVAC) I wouldn't recommend it. Just add a new circuit. And remember to add up all of the power, a 400W HPS draws 480W of power, dont forget the ballast needs power too. [SIZE=-2]If you can't find either amps or watts here's a way to convert: Amps x Volts = Watts, U.S. electricity = 120 volts. So something pulling 4 amps uses 4 x 120 = 480 watts. In England and other countries use 240 instead of 120, [/SIZE]use 240 in your calculations.
Thanks for the reply. Im not using HPS just FL so no hidden watts. My HVAC is pretty standard and about 5 years old so I'm assuming its fairly efficient and doesnt use more than the typical 800W. So amps for this should be 800/120 = 6.66 (hmmm, thats ominous). If I keep my grow wattage below 500 = 4.16A (I plan on actually using 400W). Im pretty sure I have that 14-2 romex too. I'm well under 15A total. Im trying to avoid pulling a new circuit. Such a nasty job in a small crawl space.
Is it a space that will be hard to get to regularly? I couldn't imagine growing without being able to check up on the plants easily when the lights are on. Also is it a space neighbors might get curious about if you suddenly start going up there a lot?
crawl space is actualy "down there" I scrapped my crawl space idea due to how much of a pain it was to get down there, and how limited verticaly i'd be. for a floro job you should be able to tap into it. dont forget your fan in your math Goodluck!