I used 'How to build a lizard cage', 'bearded dragon cages', 'bearded dragon enclosure' 'reptile cages' as key words and you get alot of hits that way. Also, click in the 'image' section of google search, and you can see just pictures.
below is one link I found that pretty much contains all you need to know about cage building and good pictures and helpful tips.
www.arbreptiles.com/cages/tips.shtml
Basically, large snake cage racks can be easily modified...just terrestrial snake cages need a bit more height.. dragon cages should be between 18-24" high. Heat tape is useless for dragons, so skip that part and mount fixtures inside on the 'ceiling' and cut holes as you need them.
I am no master electrician...but some basic things to keep in mind..is getting fixtures that can handle the wattage/amperage of your lights. Thus ceramic fixtures are good for basking lights and the UVB fixture should be the length of the cage, or at least 2/3rds of the cage length...A double fixture works as you can increase overall light in the cage by having one full spectrum bulb and one UVB producing bulb. The full spectrum light fixtures are cheap...maybe $5 or less. (for a 4' long one)
If you have to attached wires directly to the fixture...make sure you use electrical tape to cover the exposed wires...or those twisty cap thingies...or use the metal' box you can get to go around the fixture to protect/cover the wires.
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PHLdyPayne