Hey, back to check up. Friend, Although Your getting a lot of advice with safty in mind, it's mostly from noobs, and most noobs do the overkill thing in everything they do. I will tell you this. YOUR EXTENTION CORD WILL WORK FINE! I use a 25 foot Orange outdoor extention cord by noma. Prolly cost 20 bucks. Using it for 3 years now, rockin a 400W HPS, with about 200w added in CFL's from veg cabs and fans ETC. And I'm fine. Been through storms, power outages, and Its all good. You wanna put your mind at ease....go try it. After 6 hours, go feel the cord in 3 different spots. The wall plug end, the splitter end and right in the middle. All your feeling for is warmpth. If any of those spots feel warmer than grabbig another persons arm, you should up your cord.