Okay here are some pictures and detailed instructions on changing the voltage and attaching the power cord.
The first picture is one of my last unconverted 400 MH high bay light.
The second picture is the basic HID magnetic ballast that has had the power cord attached and the socket/reflector assembly separated from it so that the ballast can be positioned remotely from the actual light. There a few reasons this is desirable. It reduces the height required for the reflector/hood which lets you grow taller plants under the same ceiling height. It lets you place the ballast close to the plugin and still put the light where ever you want to use it so long as your cord is long enough to reach. It lets you raise/lower or relocate the light without fighting the weight of the ballast. Also if heat is a real critical problem, you can even locate the ballast outside of the grow room/tent.
The third picture is of an unconverted HPS that I just acquired. I have started the voltage conversion and attaching the power cord, by opening the access cover to the wiring cover plate. This power cord conversion is exactly the same as with my MH light/ballast assemblies.
The fourth picture is a short power cord with the outer insulation split and the inner three wires bent out to illustrate what I did. I use a retractable razor/utility knife. Be very careful while splitting the outer insulation jacket that you do NOT cut the inner insulation or yourself. then you need to disconnect the COM wire by unscrewing it and then strip the insulation on the inner power cord wires back the same length as the exposed wire on the COM wire.
The fifth picture is the power cord and COMmon wire connected with the
original wire nut laying on top of a piece of white paper just loose between the wires and the top of the ballast to better show the wiring stuff.
The inner insulation has been stripped away to expose the copper wire. Then the wire nut was twisted counter clockwise to remove it from the old white wire and the COM wire; the COM wire and the white wire from the new cord laid parallel and the wire nut twisted back on clockwise.
The next step is to do the same thing with the green wires, if there is one. Then unless the old black wire is connected to the 120V wire on the ballast you will need to remove the wire nut, cut the exposed wire off flush with the insulation on what ever voltage wire it was connected to, fold the insulated wire tightly back over and wrap it with electricians tape. (There are other acceptable ways to prevent the old ballast wire from shorting but this is the best way to do it.) I don't have a picture of this step but mojavemama does, so we will try to get her to post it. She also has some other detailed pictures of stuff I just forgot to record as it did it.
The you find the 120V wire and uncap the end of it -- It usually has some kind of blank connector crimped to it that you nee dot cut off.-- strip the insulation back, lay it parallel to the black cord wire and twist the wire nut back on.
Before you start connecting the power cord, make sure to remember to route the cord through the old wire hole so you can close up the wiring area with the cover plate.
Once you have the wiring taken care of securely screw a know to be good bulb into the socket but do NOT OVER TIGHTEN IT, position the ballast so that the bulb isn't touching any thing and noting will fall, plug the power cord in and wait to see if the bulb lights. Don't look directly at the light or you will have temporary blindness when you look away -- don't worry you will be able to tell if it lights.
If it lights then you're good to go and can decide from there whether or not you will use the light the way it is or convert it to a remote ballast light type. If it doesn't light with in 5 minutes it probably will never light. Either way unplug the power cord. Always wait until the bulb is cool to the touch and handle it with either clean soft gloves or clean hands to avoid getting spots on the bulb. Never try to restart a hot or even fairly warm HID bulb. If you must restart it quicker, then replace the bulb with a cool bulb.
If you are going to convert it to remote ballast or change the reflector/hood, then study my thread under my signature.
If you followed the steps and had a good bulb in a good ballast you should now have as functioning light.
If you have any trouble, do NOT be shy about asking for help. Remember electrical equipment can kill or cause large fires if not done right so PLEASE make sure you understand it and have it done right BEFORE YOU PLUG IT IN.
For some reason the pictures won't up load so I'll have to try it later. We will have to wait for one of themoderators or staff to help me. Ozzy, I completely changed the file names and locations on disk and it still keeps coming up that I have already upload the file. Thanks buddy.
Good smoking!