Spooks - it's 123x140 foot area. I'd prefer the three prong plugs because we would like to be able to move the lights when they aren't needed (like the summer when it's light out until late in the evening). We found some special covers for the three prong plugs that make them safe in the weather. My husband did bring up a good point about the circuit breaker in the barn, so I guess I'll need to look into that too...