I agree with Joshua concurring with Chris15. Get someone to work with you on this.
With that as a caveat...Now, as for the actual
fixture. Does it actually have a
ground cable in the leads? If so, you may want to put a
connector on the leads and attach a complete extension cable to it (that way you don't have to worry about
wire nutting bare leads). It makes things cleaner and safer. From the original post, it sounds like you have an actual Street Lamp, which would have a
ground cable as part of the
ballast system. If you just have a simple
fixture that isn't grounded (like from a household floor lamp) then maybe you will want to find a better
fixture that HAS a
ground lead. Another poster mentioned keeping the actor from turning the light off by a
switch...I disagree from an artistic
point of view because there is ALWAYS a
lag between actions taken by 2 different people. That being said, you are putting an actor in charge of an electrical device you have wired. Is it safe for that actor to use without the potential for hurting themselves or others? This is where a properly grounded
fixture comes into
play. If the
fixture isn't grounded and there is an electrical fault, electricity will ALWAYS try to find the easiest path to
ground, (and taking into account all of the jokes concerning actors not being very grounded...) that may very well be THROUGH the actor. Not good.
Please consider very carefully utilizing an electrical device you are not fully knowledgable about. Please get help with this device.