Ok, deep breath ace ventura style:
Projector lamps are fussy creatures.... Dedicated circuits minimize the chance of having a sudden volt bump or sag that is detrimental to bulb life. A dedicated circuit to the PJ also allows the future application of an APC backup in your electrical room to allow proper shutdown of you PJ in the case of a power outage.
I have done a couple of home theaters for others and a large live stage venue this way and there is zero issues with their installation. A good electrician will think about the loads on a circiut (especially if they are specific and dynamic) and go the safe route of dedicated breakers.
A little history.... my basement HT was pre wired by a previous owner on one circuit for the room. It includes 5 receptacles and 2 light locations- well within code. I left the AVR and subs on it along with the bluray player and PS3. The projector was later fished in as a dedicated circuit. However the dual SVS SB12-NSD subs sharing the circuit with everything else causes issues. The lights dim when they first power up (volt sag from inrush) and when listening to music they dim periodically. This means the same sag experienced by the lights is also affecting other loads on the circuit ie. avr and bluray player.
Heat is not the only enemy of electronics. Dirty power and volt sag/bumps will eventually take its toll on electronics. Theoretically, if heat was controlled and power was filtered properly, a well designed piece of gear would last literally forever. Properly loading circuits and eliminating noise will save you the "need" of a power conditioner. You will never complain of picture noise, subwoofer hum or other gremlins. Remember the same bus is a necessity.
If the PJ was subjected to this form of circuit I would be on at least my second if not third bulb at 1000hrs or so. That is why whenenver anyone complains in forums about bulb life or flickering light output I ignore them. They are wired wrong for the application. Hope this explanation helps!!!
BTW, I can't wait to move into my new house and build out the basement properly!!
Everytime I see a great setup like NickBuol's or the installs I've done I'm green with envy. It's like by day I work on Ferarris but drive home in a pinto! LOL!
